Table 3

Quality of Sleep Obtained by Battalion Staff Members - Insurgency Phase
(Days 1-10)

Percentage of Total Sleep Percentage of All Sleep
Classified as Restless Periods 10 Minutes or Less
(Fragmented)

Subject M sD x sD
s1 6.2 1.9 60.5 6.0
S2 8.5 2.8 59.3 13.7
FSO 12.1 3.0 63.5 11.9
$3-Air 9.5 3.2 69.2 7.0
xO 8.6 2.2 55.5 14.0
s3° a--- wee wees weee
$3-Plans 15.5 1.9 73.3 4.0
s4 19.3 2.9 76.1 8.8
$3-Train. 9.6 3.7 56.3 7.9
ADO 9.1 2.0 51.8 10.9

Wnalyses could not be performed for any of the days during this phase due to
equipment malfunction.

Nete. Means based on 7-10 days of data for each subject. Missing days were the
result of either equipment malfunction or incomplete data which could not be
accurately analyzed.

Fragmented sleep, defined as the percentage of sleep consisting of sleep periods of 10
minutes or less, was fairly high. During the Insurgency phase, an average of 62.4% (SD =
12.5%) of the staff members’ sleep could be classified as fragmented. Individual percentages
ranged from an average of 51.8% to 76.1% per day (see Table 3).

12



Minutes Slept

Percentage

700

600

500

400

300

200

100

120
110
100
90
80
70
60
50
40
30
20
10

Optimal Sleep Off Rotation Sleep

Sleep on Rotation (480 minutes)

1 2 3 4 5 6 7 8 3 10 #11 #12 #13 #14 «+15 16
Day
Figure A-15. Comparison of Rotation Sleep vs Individ. Sleep Requirements - $4.
Z Movement Fragmentation
{% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
= —o— ———
im)
q e
L 1 a 1 ! Hl L mn n j 1 1 n L r n
1 2 3 4 5 6 7 8 9 10 11 12 13414 «#15 16
Day

Figure A-16. Quality of Sleep by Day - S4.

A-8



700

600

500

Minutes Slept
aS
°
3

300

200

100

120
110
100
90
80
70
60

Percentage

50

40

30

20

10

Rotation Sleep

Optimal Steep
(420 minutes)

(420 minutes)

i 1 i nl L i i i r n i 1 n L i

Off-Rotation Sleep

1 2 3 4 5 6 7 8 9 10 11 #12 #13 #14 «+15 = 16
Day

Figure A-7. Comparison of Rotation Sleep vs Individual Sleep Reqmnts. - $3-Air.

a Movement Fragmentation

a (% Restless Sleep) (% Sleep Pds. 10 Min. or Less)

a
1 L i" L 1 il 1 L il L 1 it 1 a 1 1
1 2 3 4 5 6 7 8 9 10 11 12 13°°«214 15 16

Day
Figure A-8. Quality of Sleep by Day - S3-Air.

A-4



Table B-3

Changes in Mood Ratings Across Phases: S1

Staff Insurgency Attack
Position: Phase Phase
si
Sleepiness M = 1.50 M = 2.00
SD = .58 sD = 1.73
Tense M = 2.00 M = 2.00
SD = 0.00 SD = 0.00
Cheerful M = 2.75 M = 2.33
sp = .50 sD = .58
Relaxed M = 2.50 M = 2.33
SD = .58 SD = .58
Irritable M = 1.50 M = 2.33
sD = .58 SD = .58
Energetic M = 2.25 M = 2.67
SD = .50 SD = .58
Focused * M M = 2.67
sD SD = .58
Jittery M
spb
Dependable M
sp
Efficient M
sD
Sluggish M
sD
* p= .05



computer with color VGA monitor and Sound Blaster compatible audio source with head
phones.

Mood scale. An 11 item computerized sleepiness-mood scale was presented prior to
the start of the SYNWORK1 session. Sleepiness was assessed using a revised six point
version of the Stanford Sleepiness Scale with the following scale values: 1) Feeling active
and vital; wide awake; 2) Functioning at high level, but not at full alertness; 3) Relaxed,
awake, and responsive but not at full alertness; 4) A little foggy, starting to let down;

5) Beginning to lose interest in remaining awake; 6) Prefer to be lying down; fighting sleep;
woozy.

The ten mood items included the following: Tense, Cheerful, Relaxed, Irritable,
Energetic, Focused, Jittery, Dependable, Efficient, and Sluggish). Items were answered using
a four point scale (1 = Not at all, 2 = Somewhat, 3 = Definitely, 4 = Extremely) based on
how the individual felt at the particular time.

Apparatus

Activity monitors. Sleep-work cycles were measured using wrist-worn activity
monitors. The activity monitors used were all the same, Model AMA-32, developed by
Precision Control Designs, Inc., Fort Walton Beach, Florida. This model measures 4.45 x
3.48 x 1.27 om., about the size of a diver’s watch. The monitor has a memory capacity of 32
Kbytes. It is highly programmable, permitting user specification of frequency passband,
threshold, and amplification factors. [See Elsmore and Naitoh (1993) for more details on
parameter settings.] These monitors are very unobtrusive. The individual straps the monitor
around the non-dominant wrist and forgets about it until it is replaced. Movements made by
the individual generate an electrical voltage, producing a signal which is stored in an on-board
memory. Activity is partitioned in "epochs" of time, usually 60 seconds in duration. For
each epoch, the number of movements occurring is counted and stored. Depending on the
monitor used and its configuration, approximately 22 days of data can be stored before data
has to be down-loaded [See Elsmore and Naitoh (1993) for more details.] Activity data were
computer scored for sleep-wakefulness and verified by an investigator. A record was scored
as sleep if there were less than 20 counts per minute for five consecutive minutes. Activity-
generated measures of sleep-wakefulness have been shown to correlate remarkably well (r >
.82) with corresponding parameters scored from the polysomnagram (Cole, Kripke, Gruen,
Mullaney, & Gillin, 1992).

Procedure

Researchers met with the staff members two months ahead of the scheduled rotation to
begin initial testing and to ensure adequate time for train-up on the SYNWORK! task.
Participants were briefed on the major objectives of the research and given the opportunity to
ask any questions about the equipment or tasks they would perform. All participants were
then given consent/privacy act statements and the Sleep History Questionnaire to complete.



Table 6

Ratio of Actual Sleep Obtained to Optimal Sleep Required for Full Recovery by Day
(1.00 = Optimal Sleep Requirements Obtained) - Attack Phase

Rotation Day
(Attack Phase)

Staff a. 12 13 14 15 16 M sD
Pos.

s1 2.03 64 68 78 62 +37 68 +22

82 339 61 61 52 60 05 +46 +22

FSO 239 251. +52 82 66 40 55 17.
S3-Air *

xo +67 64 01 78 66 +58 56 +27

83 78 +65 50 1.00 +80 +25, +66 +26
$3-Plans | .48 18 62 69 63 59 53 +19

s4 +96 +96 ---
83-Trn. 62. +60 +68 +71 +35 1.23 +70 129
ADO 40 41 35 69 +97 08 48 231 =
Mean +59 58 +50 275 66 44 60 ---

sD +23, 222 +22 +14 17 238 | --- +23,

= mmpty cells indicate data was collected but could not be used in the analyses
due to equipment malfunction.

During the Attack phase, the $2 (46%) and ADO (48%) were the most sleep deprived.
They were followed by the S3-Plans (53%), FSO (55%), and XO (56%). The $3-Training
(70%), S1 (68%), and S3 (66%) were the least sleep deprived. The S4 had only one valid
day of data which could be scored during this phase. With the exception of the S1,
ITSACORR results revealed no statistically significant differences in staff members’ NSI
scores between phases. The S1 obtained significantly more of his sleep requirements during
the Attack phase (68%) than he did during the Insurgency phase (62%), F(2,11) = 5.87, p =
.018.

Comparison of the activity patterns of the individual staff members showed that the
$2, $3-Plans, FSO, and XO were the most sleep deprived across phases. For other staff
members, such as the ADO, sleep patterns changed radically across phases, going from sleep
during the evening (Insurgency) to greatly reduced sleep periods obtained primarily during the
day (Attack). The activity data showed that some staff members’ sleep was far less
fragmented than others. This was reflected in the fragmentation scores (Tables 3 and 4).

16



700

600

500

Minutes Slept
oN
°
ro)

300

200

100

120
110
100
90
80
70
60

Percentage

50
40
30
20

10

Rotation. Sleep Optimal Sleep Off-Rotation Sleep

L 1 ! ! ! ! Lt J 1 ! n ! L 1
8 9 10 11 #12 #13 #14 «+16 16
Day

Figure A-17. Comparison of Rotation Sleep vs individ. Sleep Requirements - S3T.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
—e— —

an

Figure A-18. Quality of Sleep by Day - S3T.

A-9



FOREWORD

As Army doctrine calls increasingly for 24-hour, continuous operations with a particular
emphasis on night fighting capabilities, opportunities for sleep continue to erode. Advances in
target acquisition, communications, and sensor systems allow soldiers to fight longer, harder, and
faster than ever before. Despite these recent technological advances, the soldier remains the key
to future operational success. It is critical, therefore, to determine how the soldier copes with the
demands placed on him in these environments.

The digitization of the modern battlefield will greatly increase the volume of information
that must be processed by the soldier. Decision time will, in all likelihood, be substantially
compressed. How long can the soldier effectively process information and make sound decisions?
Soldiers, unlike machines, cannot operate around the clock without letup. They need time to
recuperate. With limited combat personnel available for future contingency operations, it is
especially critical that effective sleep/work plans be developed to enable the individual and the unit
to sustain performance at acceptable levels for as long as possible.

To address this issue, sleep, mood, and work performance patterns of 10 members of a
battalion staff were tracked during a low-intensity conflict scenario. This research was based, in
part, on earlier findings from the Army Research Institute Infantry Forces Research Unit’s
(IFRU) work in the areas of battalion staff training and synchronization. This report summarizes
IFRU’s work on sleep/work load issues during the past 2 years.

Preliminary results from this research area were briefed to the Deputy Commander,
Operations Group, Joint Readiness Training Center IRTC), in May 1994. Final results from this
research were briefed to the Commander, JRTC, in December 1995.

ZITA M. SIMUTIS EDGAR M. JOHNSON
Deputy Director Director
(Science and Technology)



Minutes Slept

Percentage

700

600

500

400

300

200

100

120
110
100
90
80
70
60
50
40
30
20

10

Rotation Sleep Optimal Sleep Off-Rotation Sleep

Day

Figure A-3. Comparison of Rotation Sleep vs Individual Sleep Requirements - S2.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min. or Less)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 #15 16
Day
Figure A-4. Quality of Sleep by Day - S2.

A-2



Table 4

Quality of Sleep Obtained by Battalion Staff Members - Attack Phase
(Days 11-16)

Percentage of Total Sleep Percentage of All Sleep
Classified as Restless Periods 10 Minutes or Less
Fragmented

Subject M sD M sD
sl 7.0 2.7 63.4 7.2
S2 16.5 9.3 66.1 24.6
FSO 11.2 6.6 49.1 12.1
S3-Aixr * cece oo: coer ecce
xO 10.8 2.8 64.8 18.2
s3 9.6 1.8 57.8 12.9
S3-Plans 10.6 3.8 61.8 7.1
s4 8.3 ihe 75.0 Siete
$3-Train. 5.3 1.2 63.5 14.3
ADO 1 2.1 59.8 7.8

*~Analyses could not be performed for any of the days during this phase due to
equipment malfunction.

Note. Means based on 4-6 days of data for each subject except the S4, who had only
one day of valid data. Consequently, the S4 was excluded from all comparisons with
other staff members and any additional statistical analyses. Missing days were the
result of either equipment malfunction or incomplete data which could not be
accurately analyzed.

During the Attack phase, fragmented sleep accounted for, on the average, 60.8%
(SD = 12.5%) of all sleep obtained by staff members. Individual percentages ranged from an
average of 49.1% to 66.1% per day during this phase (see Table 4).

Fragmented sleep scores for the group (average) showed little change over time.
ITSACORR results revealed no statistically significant differences in fragmented sleep
obtained for any staff members between phases. See Appendix A for a graphic portrayal of
each staff member’s movement and fragmentation scores by day.

13



Table 9

SYNWORK1 Performance Trends Across Phases: S1

Staff Position: Insurgency Attack Phase
s1 Phase Sessions = 7
Sessions = 7
Composite M = 677.4 M = 726.0
Score* SD = 81.6 SD = 57.6
Sternberg M = 141.4 M = 138.6
Memory SD = 15.7 SD = 10.7
Arithmetic M = 321.4 M = 368.6

SD = 54.6 SD = 42.2
Visual M = 106.0 M = 110.3
Monitoring SD = 28.5 SD = 19.8
Auditory M = 108.6 M = 110.0
Monitoring sD = 10.7 SD = 12.9
*p< .05
Table 10

SYNWORK1 Performance Trends Across Phases: FSO

Staff Insurgency Attack Phase
Position: Phase Sessions = 3
FSO Sessions = 8
Composite M = 612.8 M = 649.0
Score SD = 79.9 SD = 75.0
Sternberg M = 120.0 M = 116.7
Memory SD = 32.1 SD = 30.5
Arithmetic M = 255.0 M = 283.3
SD = 49.3 SD = 80.8
Visual M = 127.8 M = 129.0
Monitoring SD = 16.6 SD = 10.4
Auditory M = 110.0 M = 120.0
Monitoring SD = 15.1 SD = 0.0

Mood Changes

Mood items were also analyzed for the S3-Plans, XO, and S1 using the ITSACORR
procedure. The FSO did not complete a sufficient number of sessions during the Attack
phase which could be validly analyzed using this procedure. With only two exceptions, the

19



Table 5

Ratio of Actual Sleep Obtained to Optimal Sleep Required for Full Recovery by Day (1.00 =

Optimal Sleep Requirements Obtained) - Insurgency Phase

(Insurgency Phase)

Rotation Day

Staff 2 3 5 6 7 9 10 M sD
Pos.

si «55 | 56 | .66 48 +92 +61 60 65 169 | .48 +62 | .13
s2 «48 | .ee | 48 +65 | 59 53 65 55 -65_ | 35 «5a | .14
Fso ~62 | .46 | .60 +69 -67 62 67 62 =36 | .64 =59 | .10
s3- .67 | .80 | .50 +68 +76 1.72 +66 +77 +82 | .38
Air

xo. «57 | 42) | .43 92 +48 +33 +72 +61 -72_| 33 +55 | .19
s3¢

s3- +88 +49 +48 +63 +55 +56 +51 | 52 -58 | .13
Plans

84 -63 | .66 | 44 64 +49 64 +22 47 +39 | 236 +49 | 115
s3- +62 | .79 | 62 1.18 | .97 1.00 | 1.07 | .70 +55 | .70 +82 | .22
Trn.

ADO «76 | .75 | 1.18 | 1.13 | 1-12 | 1.29 | 1.28 | 1.08 | .72 | .54 «98 | .27
Mean .64 | .66 | .60 +76 +75. 82 +71 87 +58 | .49 -67 | ---
sp «12 | .17_ | .23 +26 +24 44 +30 +18 +14 | .14 --- | .25

© Empty cells indicate data was collected but could not be used in the analyses due to equipment
malfunction.

Individual trends, NSI scores were then averaged across days. Mean NSI scores
were calculated for each staff member, by phase, and are shown in Tables 5 and 6. During
the Insurgency phase, the $4, XO, S3-Plans, S2, and FSO were the most sleep deprived based
on their self-reported sleep needs, and how much sleep they actually obtained during this
phase. These individuals received, on the average, anywhere from 49% (S4) to 59% (FSO) of

their daily sleep requirements. The S3-Air, S3-Training and ADO were the least sleep

deprived, obtaining, on the average, 82% (S3-Air and S3-Training) to 98% (ADO) of their
daily sleep requirements.

15



Minutes Slept

Percentage

700

600

500

is
3°
to)

300

200

100

120
110
100
90
80
70
60
50
40
30
20

10

Rotatigg Sleep Optimal Sleep Off-Rotation Sleep

1 n
1 2 3 4 5 6 7 8 9 10 11 #12 #13 #14 «15 «16
Day
Figure A-5. Comparison of Rotation Sleep vs Individ. Sleep Requirements - FSO.
z Movement Fragmentation
3 (% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
1 mn L
1 2 3
Figure A-6. Quality of Sleep by Day - FSO.

A-3



Table 1

Summary Characterization of Staff Sleep Periods - Insurgency Phase

(Days 1-10)

Number _ of Longest Uninterrupted

Hours Slept/Day Sleep Period/Day (Min)
Subject x sD M sD
sl 6.03 1.24 57.0 15.4
S2 4.65 1.12 52.2 15.7
FSO 5.05 0.87 64.3 13.8
S3-Air 5.73 2.60 64.2 70.3
xO 4.42 1.55 38.0 9.1
S3°% 0 wenee wees a a
S3-Plans 4.60 1.05 27.7 6.2
s4 3.95 1.18 33.5 7.5
S3-Train. 5.73 1.53 50.1 23.3
ADO 7.87 2.13 69.8 18.0

Wnalyses could not be performed for any of the days during this phase due to
equipment malfunction.

Note. Means based on 7-10 days of data for each subject. Missing days were the
result of either equipment malfunction or incomplete data which could not be
accurately analyzed.

Table 2
Summary Characterization of Staff Sleep Periods - Attack Phase
(Days 11-16)
Number_of Longest Uninterrupted
Hours Slept/Day Sleep Period/Day (Min
ubject M sD M sD
sl 6.64 2.11 58.5 15.8
s2 3.71 1.75 32.3 19.7
FSO 4.69 1.40 55.7 17.7
S3-Adr S00 ----- eee — -e--
xo 4.46 2.19 36.2 18.8
s3 5.62 2.22 89.8 51.3
S3-Plans 4.25 1.50 30.7 9.5
s4 7.65 193.0 erc-
§3-Train. 4.90 2.01 50.2 12.8
ADO 3.85 2.47 57.8 12.0

Analyses could not be performed for any of the days during this phase due to
equipment malfunction.

Note. Means based on 4-6 days of data for each subject except the S4, who had only
one day of valid data. Consequently, the S4 was excluded from all comparisons with
other staff members and any additional statistical analyses.

10



casualties (Belenky, 1995). This is particularly true if the individual holds a key position in a
complex system, e.g., FDC team or tank/Bradley crew member. As Belenky (1995) notes,
sleep loss can cause soldiers to lose battlefield awareness and the ability to integrate
information into a coherent and accurate representation of the tactical situation.

Sustaining Performance Through Sleep Management

To sustain high levels of productivity in continuous operation environments, the unit
must maintain an efficient balance of sleep and work (Hursh & McNally, 1993). Unit sleep
management plans play a critical role in extending performance effectiveness. An effective
sleep plan will provide regular opportunities for the soldier to sleep. The only remedy for
sleep loss is sleep; rest is not the same as sleep. Recent research (Chaisson, 1994; Belenky,
1995) suggests that six to eight hours of continuous sleep will sustain performance
indefinitely. Four to five hours of sleep will maintain acceptable levels of performance for
five to six days (Chaisson, 1994). Heavy operational demands, however, may greatly reduce
the quality of these truncated sleep periods (by fragmenting sleep and severely disrupting
circadian rhythms), which will lessen the sleep period’s recuperative value.

Sustained periods of partial sleep loss, e.g., four to five hours sleep per day, over
several weeks, can lead to performance degradation from the cumulative impact of partial
sleep loss. Obtaining even one hour less sleep than required can affect waking levels of
sleepiness (Carskadon & Dement, cited in Rosekind et al., 1994). Unless soldiers are given
enough time to adequately recover (see Chaisson, 1994), performance could suffer
significantly as a result of increased operational demands, cumulative sleep debt, and circadian
disruption.

Effectiveness of Sleep Management Plans:_An Empirical Examination

Observer/Controllers. Work load issues are critical not only in combat but in training
as well. Future reductions in training cadre, specifically, the observer/controllers (O/Cs) at the
combat training centers has generated questions concerning the potential impact of increased
O/C work load on O/C job performance. Preliminary observations (Pleban, Valentine, &
Thompson, 1994) made at the Joint Readiness Training Center (JRTC) with battalion level
O/Cs showed that they averaged anywhere from 4.7 to 6.3 hours of sleep per day across a
three phase 21 day rotation. Although cognitive performance, measured by a computerized
synthetic work task, did not degrade over time, there were clear subjective effects of sleep
loss. More specifically, O/Cs felt significantly more irritable, less energetic, and less focused
during the last phase(s) of the rotation, when compared to earlier phases. Sleepiness increased
significantly during most of the rotation. The rotation-based sleep schedule was not effective
in preventing decrements in the subjective quality of sleep. O/Cs felt that their present rest
intervals (between rotations) did not provide sufficient time to recover from the effects of
mental fatigue. Fifty percent of the O/Cs felt that their present work load was excessive.
While current O/C sleep-work cycles appeared to be effective on a short term basis in
sustaining performance, the subjective data clearly showed the negative impact of partial sleep



Elsmore, T. F. (1994). SYNWORK1: A PC-based tool for assessment of performance in a
simulated work environment. Behavior Research Methods, Instruments & Computers.
26(4), 421-426.

Elsmore, T. R., & Naitoh, P. (1993). Monitoring activity with a wrist-worn actigraph: Effects of
amplifier passband and threshold variations (Report No. 93-18). San Diego, CA: Naval
Health Research Center.

Haslam, D. R., Allnutt, M. G., Worsley, D. E., Dunn, D., Abraham, P., Few, J., Labuc, S., &
Lawrence, D. J. (1977). The effect of continuous operations upon the military
performance of the infantryman: Exercise “Early Call” (Report No. APRE 2/77).
Farnborough, Hants, United Kingdom: Army Personnel and Research Establishment.

Hursh, S. R., & McNally, R. E. (1993), Modeling human performance to predict unit
effectiveness. In D. Kamely, K. A. Bannister, & R. M. Sasmor (Eds.), Army science: The
new frontiers-military and civilian applications (pp. 309-328). Saratoga, WY: Borg
Biomedical Services.

Mullaney, D. J., Kripke, D. F., Fleck, P. A., & Johnson, L. C. (1983). Sleep loss and nap effects
on sustained continuous performance. Psychophysiology, 20(6), 643-651.

Pleban, R. J., Valentine, P. J., & Thompson, T. J. (1994, May). Work-rest patterns of
observer/controllers at the Joint Readiness Training Center: An assessment of cognitive

work load capabilities. Briefing presented to the Deputy Commander, Operations Group,
Joint Readiness Training Center, Fort Polk, LA.

Rosekind, M. R., Gander, P. H., Miller, D. L., Gregory, K. G., Smith, R. M., Weldon, K. J., Co.
E. L., McNally, K. L., & Lebacqz, J. V. (1994). Fatigue in operational settings: Examples
from the aviation environment. Human Factors, 36(2), 327-338.

Thompson, T. J., Thompson, G. D., Pleban, R. J., & Valentine, P. J; (1991). Battle staff training
and synchronization in light infantry battalions and task forces (Research Report No.
1607). Alexandria, VA: U.S. Army Research Institute for the Behavioral and Social
Sciences (AD A245 292)

26



Recommendations

Sustaining Staff Performance

Better distribution of staff work load. In operational settings, either simulated, like
JRTC, or actual combat, sleep loss will occur. The solutions for minimizing sleep loss effects
may vary, depending on the unit. Interviews conducted with staff members and senior
officers suggested that some of the problems leading to sleep loss and excessive work load are
due to inefficient utilization of staff/TOC resources. Staff work loads can be reduced by
better distribution of duties. Recent observations (CALL, May, 1995) by O/Cs at the National
Training Center indicate that certain staff positions, e.g., XO and S2 are over utilized; often
these individuals end up performing tasks that can be done equally well by other staff
members. The results from this research indirectly confirmed these findings by clearly
showing that the XO and S2, were two of the most sleep deprived staff members during the
rotation.

As was noted earlier, XOs and battle captains attempt to accomplish many TOC tasks,
with little or no assistance. from the NCOs or enlisted personnel. The unwillingness to
delegate these tasks to these individuals leads to inefficient operations, not to mention tired
and ineffective staff members. Moreover, it prevents the XO or battle captain from doing his
main job of integrating resources and synchronizing the fight. Lack of clearly defined roles
and responsibilities is the major contributor to this problem. See FC 71-6, Battalion and
Brigade Command and Control (March 1985), for a detailed list of duties and responsibilities
for key personnel within the TOC.

CALL Newsletter 95-7 details the roles and responsibilities of four positions and
discusses ways these individuals can be utilized more effectively than they are currently.
These positions include the XO, battle captain, operations NCO/shift NCO, and Radio
telephone operators (RTOs). Liaison officers can also be employed more efficiently. They
can be particularly valuable in assisting the S2 in the planning process, specifically in the
development of the IPB.

In summary, the keys to more efficient utilization of personnel begin with defining
specific TOC functions and identifying which duty position will accomplish each task; and
focusing home station training on those TOC activities where staff weaknesses exist (CALL,
May, 1995).

Developing procedures for processing/managing information flow in the TOC. As

fatigue increases, the ability to manage information and track the battle suffers. This finding
could not be confirmed, however, in the present research. This would have required continual
on-sight monitoring of TOC activities for the entire sixteen day rotation. Lack of resources,
both human and financial, precluded this type of investigation. Nevertheless, a process-
oriented investigation of staff procedures for distilling information and tracking the course of
the battle flow in the TOC would be useful because of the critical nature of such activities.

22



OO

CHARACTERIZATION OF SLEEP, MOOD, AND PERFORMANCE PATTERNS IN
BATTALION STAFF MEMBERS AT THE JOINT READINESS TRAINING CENTER

CONTENTS

INTRODUCTION o.0....c.cccccccceccsseeseseeessescssssssnssesnssesssesssessssussssissssieassueensuessssesseuensenerereenseentees 1

Sustaining Performance Through Sleep Management ................c0ccccceseseeeeteeeteieeneees
Effectiveness of Sleep Management Plans: An Empirical Examination.....
Objective oe. ees ree eseecseeeessesseeissneaseesesieesnsenssiesneensenseneene .

Participants
Materials ...
Apparatu
Procedure...

OPFOR Sleep History
Characterization of Actual Sleep Periods
Battalion Staff Sleep Requirements
OPFOR Work Load Levels...
SYNWORK1 Performance
Mood Changes

DISCUSSION ........ccccscsecscesessesescesesseseseeesssucsesssesssssscsusssessssssssecessussssusssaucesseessusveseseasenensenenees 20

Sleep Quality
Performance and Mood Changes Over Tim

RECOMMENDATIONS .......0.cccccccccececssesestesestesesnesessssesnssseissesenesnsensneensisensrseisrsrieieeeteeeentenees 22

Sustaining Staff Performance ....

CONCLUSIONS 0.00... cescecssessseessesssecsesensesecenessessressvetsessecsaesseetavessvetsuesnetsisesessreseressessseeseesees 23
REFERENCES 0.o...cccccccccecececescscecsscecsesscscsecssssseeesscsenesssessssisesasseecssessenscsessscssseesesenasens 25
APPENDIX A. Graphic Summary of Individual Changes in Sleep Duration and Sleep
Quality by Day... ccc ccc enescsesesesiesesesssserssseissssisssiisieisaeeeeeeenes A-l
ix



CHARACTERIZATION OF SLEEP, MOOD, AND PERFORMANCE PATTERNS IN
BATTALION STAFF MEMBERS AT THE JOINT READINESS TRAINING CENTER

EXECUTIVE SUMMARY

Research Requirements:

New technologies combined with the adoption of a force projection doctrine have greatly
increased the tempo of modern warfare. These technological advances enable units to fight
longer, harder, and faster than ever before.

Soldiers, however, can only work or fight so long, and then must be given some time to
recuperate. With limited combat personnel available for future contingency operations, it is
especially critical that effective sleep/work plans be developed and strictly adhered to by unit
members.

Procedure:

This research tracked the sleep/work patterns of 10 members of a battalion staff during a
low-intensity conflict scenario. Sleep patterns were captured by wrist-worn activity monitors that
permitted minute-by-minute assessment of the activity levels of each staff member. Selected staff
members were monitored over a 16-day rotation.

Data on staff sleep habits and perceptions of work load levels were collected using paper-
and-pencil questionnaires. Daily estimates of cognitive work capacity were obtained using a
computerized synthetic work task. In addition, a brief computerized sleepiness-mood scale was
presented each day.

Findings:

The average daily sleep obtained by the staff members was 5.2 hours (range 3.5-6.4
hours). They averaged almost 3 hours less sleep per day than was needed for total recovery.
Certain staff positions received very little sleep across the exercise. Over 60 percent of the sleep
obtained was fragmented in nature (sleep periods of 10 minutes or less). Substantial increases in
response variability were noted for one staff member, which is indicative of how performance
degrades in continuous operations environments.

Utilization of Findings:

This research suggests that to effectively sustain staff performance during continuous
operations, commanders must take an active role in the development and implementation of unit
sleep/work management plans. By optimizing the recuperative value of available sleep periods, an
effective sleep management plan can provide commanders with a powerful force multiplier.



Statistical analyses of changes in individual staff member’s sleep times between phases
were performed using an interrupted time series analysis called ITSACORR (Crosbie, in
preparation). Unlike other time series analysis procedures, ITSACORR does not require a
long series, or set of data points, e.g., n = 50 per phase, as do some procedures, and it
controls effectively for high levels of positive autocorrelation between scores. ITSACORR
procedures are based on the interrupted time-series experiment (ITSE) model with specific
modifications to provide better control of Type I error and acceptable power for small sample
sizes, e.g., < 10 observations per phase. The results of these analyses showed, for the most
part, no statistically significant differences between phases for individual staff members. The
only exception was the $1, who got significantly [F(2,11) = 5.87, p = .018] more sleep during
the Attack phase [M = 6.6 hours (398.7 minutes)/day]) than during the Insurgency phase [M =
6 hours (362 minutes)/ day]. (See Tables 1-2.) Analysis of the activity data for each soldier
showed that sleep was not obtained in a single uninterrupted block. Instead, sleep periods
were frequently broken into several periods. Interruptions in sleep were usually only a few
minutes in duration. The longest uninterrupted sleep periods (mean times for individual staff
members) during the Insurgency phase ranged from 27.7 minutes to 69.8 minutes. The
overall average for the staff was 51.1 minutes (SD = 28.2 minutes) During the Attack phase
the longest uninterrupted sleep periods ranged from 30.7 to 89.8 minutes. The staff average
was 53.7 minutes (SD = 31.7 minutes) [See Tables 1-2].

Sleep quality: Movement during sleep and sleep continuity. The recuperative value
of sleep is dependent not only on the duration of sleep, but the quality of sleep as well. Sleep
quality was assessed by examining the restlessness (movement) of individual staff member’s
sleep and sleep continuity. Continuity refers to whether the individual obtains sleep in one
block or smaller, fragmented bits over time. With regard to movement during sleep or
restlessness (defined as > 5 < 20 movements per minute), an average of only 10.8%

(SD = 4.7%) of the staff members’ sleep could be classified as restless during the Insurgency
phase. Restless sleep accounted for as little as 6.2% and as much as 19.3% of individual staff
members’ total sleep (See Table 3).

Restlessness was also low during the Attack phase, averaging 9.4% (SD = 5.2%)
during this time. During this phase, restless sleep accounted for anywhere from 5.3% to
16.5% of an individual’s total sleep (see Table 4). Daily fluctuation in the overall staff
average over time was negligible. ITSACORR results indicated, with one exception, that staff
members’ restlessness/movement levels (during sleep) did not change significantly between
phases. Figure 2 shows very little fluctuation in the overall staff average over time.

11



CHARACTERIZATION OF SLEEP, MOOD, AND PERFORMANCE PATTERNS IN
BATTALION STAFF MEMBERS AT THE JOINT READINESS TRAINING CENTER

Introduction

The battlefields of the future are likely to be chaotic, intense, and extremely lethal.
New technologies combined with the adoption of a force projection doctrine have greatly
increased the tempo of modern warfare. Advances in target acquisition, communications,
sensor systems, and the almost complete mechanization of land combat forces enable units to
fight longer, harder, and faster than ever before [Chaisson, 1994; FM 22-9, Soldier

Performance in Continuous Operations (September 1991)].

Continuous operations, the type of high intensity, fast paced, extended operations
described above, will put tremendous stress on the soldier’s recuperative abilities.
Opportunities for sleep, while possible, may be brief or fragmented in such situations. By
altering the duration, continuity, or timing of sleep, a host of 24 hour (circadian) rhythms are
disrupted, which can lead to decreased waking alertness and impaired performance (Bonnet,
1985). Individuals at most risk during continuous operations are those with heavy cognitive
work load requirements. Soldiers who must process and evaluate large amounts of
information such as fire direction center crews (FDC), radar operators, tactical operations
center (TOC) members, and leaders at all levels are most susceptible to the effects of
continuous operations. Effective cognitive performance is critical for conducting the
appropriate command, control, communication, and intelligence activities required for
successful combat operations at all levels, from crew, squad, and platoon through division and
corps (Belenky et al., 1994).

Studies have found that the upper limit for working intensively and continuously
without the stress of actual combat is 2-3 days (Banderet, Stokes, Francesconi, Kowal, &
Naitoh, 1981; Haslam et al., 1977). By simulating certain stressors normally found under
combat conditions (e.g., heightened work load) significant decrements in cognitive
performance and measurable fatigue effects have been reported after less than 24 hours of
sustained work (Angus & Heslegrave, 1985; Mullaney, Kripke, Fleck, and Johnson, 1983).
Mental functions degrade much faster than motor skills. Increasing sleep loss can also lead to
deterioration in mood such as increased irritability, negativity, sleepiness and decreased
motivation (FM 22-9; Chaisson, 1994).

Poor decision making is often noted after the first 24 hours of sleep deprivation.
Difficulties in processing information increase over time. Individuals require increasingly
longer time to understand oral, written, or coded information. In terms of operational
effectiveness, this translates to difficulties with spot, status, or damage reports and problems
in assessing even simple tactical situations. In addition, response time becomes more uneven,
attention span narrows and frequent lapses in responsiveness are noticeable (FM 22-9). In an
operational setting, if thinking becomes so slow or uneven that a correct decision cannot be
made within a specified time period, catastrophic system failure may occur, e.g., friendly fire



OPFOR Work Load Levels

Sixty percent of the staff felt that their work load was excessive. Staff members
indicated that they needed, on the average, 2.75 days [(SD = 2.30 days) (Range = 0-10 days)]
for full recovery from the effects of the rotation. Most staff members (70%) felt that there
should be more recovery time between rotations (an extra 3-7 days). Some staff members felt
that work loads could be reduced by (better) distributing duties to others, utilizing staff
members more efficiently, adding more officers/NCOs to pull duty, lightening rotational and
unit requirements, and increasing the planning time between rotations.

SYNWORK1 Performance

Inspection of the SYNWORK| data files indicated that only four of the ten staff
members completed enough trials to be considered even marginally acceptable for further
analyses. The four subjects, S3-Plans, XO, S1, and FSO, all had completed six 5 minute
training sessions, and at least three sessions for each phase. ITSACORR procedures were
performed on each of the four SYNWORK1 subtasks (Sternberg Memory, Arithmetic, Visual
and, Auditory Monitoring), as well as on a Composite score for each of the four staff
members.

ITSACORR results revealed no significant differences between phases in the data for
the S3-Plans and the FSO. For the XO, significant [F(2,7) = 7.15, p = .02], phase differences
were obtained for the Visual Monitoring task, with performance improving significantly
during the Attack phase relative to the Insurgency phase. The S1 obtained significantly
[F(2,9) = 5.38, p = .03] higher Composite scores during the Attack phase than during the
Insurgency phase. Tables 7-10 show the mean scores for each phase by staff member.

There were differences in performance stability among staff members. The S3-Plans,
while improving his overall score across phases, showed increased variability in his
responding across time for all four SYNWORK1 tasks. The standard deviation for the S3-
Plans’ Composite score for the Attack phase was nearly six times the size of his Composite
score standard deviation during the Insurgency phase (See Table 7). It should be noted that
during the Insurgency phase, the S3-Plans’ sleep was far more fragmented (mean percent of
total sleep that was fragmented = 73.3%) than the other staff members’ sleep (XO = 55.5%;
S1 = 60.5%; and FSO = 63.5%). For the other staff members, performance stability
improved across phases. In each case, performance stability improved on four of the five
SYNWORK1 measures (See Tables 8-10).

Mean SYNWORK1 composite scores increased over phases for each staff member. In
each instance, these improvements can be attributed primarily to sizable increases in
Arithmetic subtask scores (Mean increase = 38.3 points, Range = 21.2-56.7 points). (See
Tables 7-10.)

17



for the Behavioral and Social Sciences

Research Report 1693

Characterization of Sleep, Mood, and
Performance Patterns in Battalion Staff
Members at the Joint Readiness
Training Center

Robert J. Pleban and Tina L. Mason
U.S. Army Research Institute

19960705 072

Approved for public release; distribution is unlimited

May 1996

DTIC QUALITY INGEECISD 2



OPFOR SLEEP HISTORY QUESTIONNAIRE

GENERAL INFORMATION

SSN (last 4) Duty position, Age.

OFF-ROTATION SLEEP HABITS

1. When not on rotation, how many hours of sleep do you get, on the average, per
night?.

(For questions 2-5 base your answers on the 24 hour clock)

2. What time(s) of the day do you usually feel most alert and awake?

a) from. to. and b) from. to.

3. What time do you usually go to bed?
4. What time(s) of the day do you feel most tired and sleepy?

a) from. to. and b) from. to,

5. What is the best time of day for you to sleep? to
6. Could you use more sleep? Yes No. If yes, how much more?.
7. Do you feel well-rested after you wake up and first get out of bed?

Always
Most of the time
Often
Sometimes
Very Rarely
—___Never

8. Do you ever have trouble falling asleep?

—__Never
Very Rarely
Sometimes
Often
Most of the time
Always



habits, both during and off-rotation; identification of performance and mood changes during
the course of the rotation; and evaluation of the effectiveness of current staff members’ sleep
schedules in sustaining performance for extended periods of time.

Method

Participants

Ten OPFOR battalion staff members from JRTC participated in this research. The
average age of the staff members was 28.9 years. Age ranged from 25 to 36 years. All
subjects were officers. Staff positions represented included the following: XO, S1, S2, 83,
$3-Air, $3-Plans, S3-Training, $4, FSO, and ADO.

Materials

Questionnaires. Two paper-and-pencil questionnaires were developed, an OPFOR
Sleep History Questionnaire (see Appendix C) and an OPFOR Work Load Questionnaire (see
Appendix D). The Sleep History Questionnaire consisted of 21 multiple choice and short
answer items. Questions were designed to elicit information on off-rotation sleep habits such
as the timing and duration of sleep, restfulness of sleep, sleep problems, on-rotation sleep
habits, caffeine, and nicotine consumption. The Work Load Questionnaire consisted of nine
short answer questions concerned with recovery time between rotations, work
schedules/habits/hindrances, work load levels, and assessment of current sleep management
plans.

Synthetic work task (SYNWORK1). Staff members’ work performance was assessed
using a computerized synthetic work task called SYNWORK1 (Elsmore, 1994). The
SYNWORK1 program was not designed to simulate any particular job. According to Elsmore
(1994), however, it does contain elements common to a number of watch-standing jobs. It
also contains two characteristics of real work performance: the presentation of concurrent
tasks and explicit.assignment of outcomes for component task performance. The program
allows the researcher to vary the difficulty levels of component tasks, the payoff matrix for
component task performance, and choice of presentation of component tasks by themselves or
in any combination to approximate key aspects of targeted jobs. The program is entirely
mouse-based, thus allowing subjects’ attention to focus exclusively on the display screen.

During a standard work session, the PC screen is divided into four quadrants or
"windows". A small window in the center of the screen is used for displaying a composite
"score" for performance on all of the subtasks. Auditory feedback is provided throughout the
session. Correct responses (those producing points) are followed by a high-pitched
"squeaking" sound, and errors by a low-pitched "burping" sound. The individual’s goal is to
earn as many points as possible during the session. This requires that the individual develop a
strategy for optimizing responses to the four tasks appearing concurrently on the screen. Each
component task is described below.



loss. When repeated over several rotations, increased sleepiness and loss of concentration will
eventually lead to performance lapses that were discussed by Belenky (1995).

Battalion staff members. The digitization of the modern battlefield will greatly
increase the volume of information that must be processed by TOC personnel. At the same
time, decision time will decrease. With the tempo of operations greatly accelerated, the use
of effective sleep/work management plans in the TOC is critical if staff/TOC personnel are to
be able to function effectively for extended periods of time.

With regard to work plans, the battalion TOC must have a simple and effective system
in place to receive and process information. Observation of units at the combat training
centers (Center for Army Lessons Learned - CALL 95-7) indicate that TOCs with established
procedures for processing messages and other types of information are more effective than
those who do not (CALL 95-7). Moreover, it was found that during fast-paced operations,
TOCs which lacked a standard set of procedures for ensuring uniformity and efficiency in
managing information traffic were quickly overwhelmed with information during the peak of
the battle and TOC effectiveness was noticeably impaired.

In addition to having a sound sleep/work plan, successful TOC operations also require
that the battalion staff and support personnel be clear about each others’ roles and duties and
their importance for mission success. Earlier research by Thompson, Thompson, Pleban, and
Valentine (1991) found, for example, that units often did not recognize the importance of
certain staff sections in planning, preparing, and executing operational missions (e.g., S1).
They also found that some staff members were not adequately prepared to carry out their
duties. O/C observations (CALL 95-7) have also noted trends for both over and under
utilizing certain staff/TOC personnel. The inefficient use of staff/TOC members can
adversely affect the functioning of the TOC as key staff members such as the XO or battle
captain spend unnecessary time talking on the radio, posting maps, and logging entries in
journals, while other TOC members stand idly by observing. This interferes with the
accomplishment of their primary jobs of integrating resources and synchronizing the fight and
cuts into their sleep periods. The utilization of key staff members in this way quickly results
in fatigue and frequently leads to ineffective job performance (CALL 95-7).

Objective

Land battles are won or lost by the maneuver battalion (CAS’, 1990). The battalion
staff plays an integral role in determining the ultimate success of the battalion by how well
they are able to synchronize the battle plan through the coordination of movements, fires, and
supporting activities. However, little, if any, empirical research exists which has examined
the adequacy of current battalion staff sleep/work management plans, or organization on work
performance.

The current research was concerned with the assessment of sleep-work schedules of
battalion staff members at JRTC. Specific focus was directed toward staff members’ sleep



Table B-1

Changes in Mood Ratings Across Phases: S3-Plans

Staff Insurgency Attack
Position: Phase Phase
S3-Plans

Sleepiness

ne
0
w
°

HE
"
w
°

0
"

we
°

Tense

Cheerful

Relaxed

Irritable

Energetic

Focused

Jittery

Dependable

Efficient

Sluggish

Note. Scale values for Sleepiness were as follows:
1 = Feeling active and vital; wide awake.
2 = Functioning at high level, but not at full alertness.
3 = Relaxed, awake, and responsive but not at full alertness.
4= A little foggy; starting to let down.
5 = Beginning to lose interest in remaining awake; slowing down.
6 = Prefer to be lying down; fighting sleep; woozy.

The remaining mood items used the following scale:
1 = Not at all; 2 = Somewhat; 3 = Definitely; 4 = Extremely



References

Angus, R. G., & Heslegrave, R. J. (1985). Effects of sleep loss on sustained cognitive
performance during a command and control simulation. Behavior Research Methods
Instruments, & Computers, 17, 55-67.

Banderet, L. E., Stokes, J. W., Francesconi, R., Kowal, D. M., & Naitoh, P. (1981). Artillery
teams in simulated sustained combat: Performance and other measures (Publication No.
81-127). In L. C. Johnson, D. I. Tepas, W. P. Colquhoun, & M. J. Colligan (Eds.), The
twenty-four hour workday: Proceedings of a symposium on variations in work-sleep
schedules (pp. 581-604). Cincinnati: U.S. Department of Health and Human Services
(DHHSCNIOSH).

Belenky, G. (1995). Sleep, sleep deprivation, and continuous operations. Army RD&A, May-
June, 23-25.

Belenky, G., Balkin, T. J., Thomas, M. L, Redmond, D. P., Kant, J. L., Thorne, D. H., Sing, H.
C., Wesensten, N. J., & Bliese, P. (1994). Report of the sleep and performance work
group division of neuropsychiatry--Walter Reed Army Institute of Research. Unpublished
manuscript.

Bonnett, M. H. (1985). The effect of sleep disruption on performance, sleep, and mood. Sleep, 8.
11-19.

Center for Army Lessons Learned (1995, May). Tactical Operations Center (No. 95-7). Fort
Leavenworth, KS: U.S. Army Training and Doctrine Command.

Chaisson, P. J. (1994). Rest for the weary: The role of sleep management in combat operations.
Armor, September-October, 14-18.

Cole, R. J., Kripke, D. F., Gruen, W., Mullaney, D. J., & Gillin, J. C. (1992). Automatic
sleep/wake identification from wrist activity. Sleep, 15(5), 461-469.

Combined Arms and Services Staff School (1990, February). Organization of the Army in the
field (E709/1). Fort Leavenworth, KS: U.S. Army Command and General Staff College.

Crosbie, J. (in preparation). Interrupted time-series analysis with short series: Why it is
problematic; how it can be improved. In J. M. Gottman & G. Sackett (Eds.), The analysis
of change. New York: Erlbaum.

Department of the Army (1991, September). Soldier performance in continuous operations (FM
22-9). Washington, DC: Author.

Department of the Army. (1985, March). Battalion and Brigade Command and Control (FC 71-
6). Washington, DC: Author.

25



9. If you do have trouble falling asleep, what it is it that keeps you awake?

Thoughts running through my mind
Aches and pains

Too much noise

Other,

10. Do you take anything to help you fall asleep?

Never

Very rarely
Sometimes
Often

Most of the time
Always

11. If you take something to help you fall asleep, what is it?
Medicine prescribed by a doctor

Over the counter medicine
List any other.

12. Do you take catnaps during the day when you are not on rotation?

Never or almost never
1 or 2 times per week
3 or 4 times per week
5 or more times per week
More than once a day

13. If you take naps, generally how long are these naps?
DURING-ROTATION SLEEP/ACTIVITY HABITS
14. During a rotation, how many hours of sleep do you get, on the average, per 24 hours?

15. Are your primary sleep periods planned or scheduled for certain times during a rotation?
Yes No. If yes, when are these sleep periods typically scheduled?

16. Do you feel well-rested after you awake from these sleep periods?

Always

Most of the time
Often
Sometimes
Very rarely
Never



As Belenky (1995) points out, once the TOC becomes overwhelmed with information
requirements, demands, updates, etc., one of the first functions to disappear or be degraded is
the ability of the staff to accurately analyze the situation. Inaccurate assessment of the
situation can have disastrous effects, such as the Bradley Fighting Vehicle friendly fire
casualties observed in Operation Desert Storm described by Belenky et al. (1994).

Conclusions

This preliminary research, together, with observations from the CTCs (CALL, May,
1995) suggests that to effectively sustain staff performance during continuous operations,
better utilization of staff resources is critical. Once tasks and duties have been assigned to
particular personnel, TOC specific tactics, techniques, and procedures identified by the
commander and his staff must be thoroughly rehearsed.

In addition, commanders must take an active role in the development of unit
sleep/work management plans (Chaisson, 1994). This includes educating unit members on the
importance of sleep in combat operations and how to optimize the recuperative value of
available sleep periods through specifically tailored unit sleep plans. The combination of
knowledge and preparedness will allow the staff to work smarter so it can work more
effectively.

23



CONTENTS (Continued)

Page
APPENDIX B. Changes in Mood Ratings Across Phases ........0....c.ccccscsscccessesesseteseseeseseeeetenene B-1
C. OPFOR Sleep History Questionnaire ..0...0.0...c.cccccecceceseeeeeeseeeeesesteteetsteeeeees C-1
D. OPFOR Work Load Questionnaire ...........ccccccccccccecsseeeesestesesesesestsseenseeeteneneeee D-1
LIST OF TABLES
Table 1. Summary Characterization of Staff Sleep Periods - Insurgency Phase..............0..0004: 10

2. Summary Characterization of Staff Sleep Periods - Attack Phase

3. Quality of Sleep Obtained by Battalion Staff Members - Insurgency Phase
(Days 1-10)..

4. Quality of Sleep Obtained by Battalion Staff Members - Attack Phase
(Days 11-16)...

5. Ratio of Actual Sleep Obtained to Optimal Sleep Required for Full Recovery
by Day - Insurgency Phase (1.00=Optimal Sleep Requirements Obtained)..

6. Ratio of Actual Sleep Obtained to Optimal Sleep Required for Full Recovery
by Day - Attack Phase (1.00=Optimal Sleep Requirements Obtained).

7. SYNWORK1 Performance Trends Across Phases: S3-Plans.............c0ccccecssssessesneetees 18
8. SYNWORK 1 Performance Trends Across Phases: XO..........c.:ccccscsssssesssssssestesneeeesees 18

9. SYNWORK 1 Performance Trends Across Phases: S1

10. SYNWORK1 Performance Trends Across Phases: FSO............cccscsssssssesssessesseseeenes 19

LIST OF FIGURES
Figure 1. Average Time Slept by Battalion Staff vs. Actual Sleep Requirement ..............00.00:00 9
2. Quality of Sleep by Day - Average Battalion Staff Scores ............c:ccccccccssestectestesesseeees 14



120 F

Movement Fragmentation
110 E (% Restigss Sleep) (% Sleep Pds_10 Min. or Less)
100 F
90 F
80 F

Percentage
[o2) ~~
o 6
:

bo P a
ooo 8
T T T T

°o

Day
Figure 2. Quality of Sleep by Day - Average Battalion Staff Scores.

Battalion Staff Sleep Requirements

Staff trends. To assess the amount of sleep deprivation for each staff member, a
normative sleep index (NSI) was created by calculating the ratio of actual sleep obtained to
optimal sleep required for full recovery. This was done for each subject by day and phase
(see Tables 5 and 6). Collapsing across subjects, mean indices were calculated for each day.
During the Insurgency phase, the overall group average during this phase was .67 (SD = .25),

indicating that the staff was obtaining, on the average, only about two-thirds of the sleep per
day they said they needed to function at full effectiveness. Daily mean fluctuations in the
| NSI ranged from .82 on Day 6 to .49 on Day 10.

During the Attack phase, the overall average NSI score for the staff was .60 (SD =
.23), indicating that the staff, as a whole, was obtaining only 60% of the sleep needed to
function at peak effectiveness. Daily fluctuations in mean NSI scores ranged from .44 (Day
16) to .75 (Day 14).

14



700

600 F-

500

400

Minutes Slept

300

200

100 bu L i 1 Ll 1 L 1 1 4 Hl L L rt n 1
1 2 3 4 5 6 7 8 9 #10 #11 #12 #13 #414 #+15 16

Day
Figure A-11. Comparison of Rotation Sleep vs Individ. Sleep Requirements - S3.

120 F

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
——

110 F

100 F
90 F

80 F

60 F

Percentage

40 F
30 F

20F

10 fF ee. ,.°

Figure A-12. Quality of Sleep by Day - S3.

A-6



Minutes Slept

Percentage

700

600

500

400

300

200

100

120
110
100
90
80
70
60
50
40
30
20
10

Rotation Sleep Optimal Sleep Off-Rotation Sleep

i i i J 4 i r i r i L 4 r L

1 2 3 4 5 6 7 8 3 10 11 #12 #13 «#14 «+15 16

Day
Figure A-13. Comparison of Rotation Sleep vs Individ. Sleep Reqmnts - S3-Plans.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min or Less)

Day
Figure A-14. Quality of Sleep by Day - S3-Plans.

A-7



analyses showed no significant changes in mood state across phases (See Appendix B).
Variability in ratings increased for many items across phases. Ratings for sleepiness, focused,
efficient, and sluggish showed increasing variability over time for all staff members (S3-Plans,
XO, S1).

Discussion

The results from this research showed OPFOR battalion staff members did not receive
the requisite amount of sleep necessary to function at optimal effectiveness during rotation.
The staff obtained almost three hours (174.8 minutes) less sleep per day, on the average, than
they indicated they needed for full recovery. Off-rotation sleep, while longer in duration,
averaged almost 90 minutes less per day than stated requirements.

Optimal sleep requirements for battalion staff members averaged 8.07 hours [(484.2
minutes) SD = .77 hours (46.2 minutes)]. This is consistent with the sleep needs for the
majority of the general population (7.5 - 8.5 hours sleep per day).

Sleep Quality

In terms of sleep quality, the results are somewhat mixed. Movement or restlessness
was fairly low throughout the rotation. However, the continuity of sleep was frequently
broken, though broken for only minutes at a time in many instances. While it is difficult to
know if the break in sleep, was, in fact, a full awakening, i.e., movement and verbal response;
or simple postural adjustment, an individual does not have to be actually awakened to dilute
the recuperative effects of sleep. Fragmentation with no obvious behavioral manifestation (a
simple change in the electroencephalogram - EEG) can, by itself, destroy the recuperative
value of sleep (Belenky, et al., 1994).

According to FM 22-9, Soldier Performance in Continuous Operations, the keys to

enhancing the recuperative power of sleep are duration and continuity. This research shows
that battalion staff members did not obtain sleep of adequate duration, and when they did
sleep it was generally fragmented in nature.

The next generation activity monitor will include additional software integrated into
the module which will predict individual performance based on recent sleep history as
measured by the monitor. These monitors can be accessed during an on-going rotation or
operation. The information obtained will indicate current sleep-work patterns, performance
effectiveness levels, and how much sleep will be required by all personnel to improve
performance and increase the probability of a successful operation (Belenky, 1995).

In the interim, activity patterns can be summarized and feedback provided to

individual staff members, and the staff as a whole to assist the staff in developing optimal
sleep-work schedules for the future. Subjective data obtained from questionnaires can also be

20



Research Report 1693

Characterization of Sleep, Mood, and Performance Patterns
in Battalion Staff Members at the Joint Readiness
Training Center

Robert J. Pleban and Tina L. Mason
U.S. Army Research Institute

Infantry Forces Research Unit
Scott E. Graham, Chief

U.S. Army Research Institute for the Behavioral and Social Sciences
5001 Eisenhower Avenue, Alexandria, Virginia 22333-5600

Office, Deputy Chief of Staff for Personnel
Department of the Army

May 1996

Army Project Number Training Systems and Education
20363007A793

Approved for public release; distribution is unlimited.



Table B-4

Changes in Mood Ratings Across Phases: Battalion Staff

Staff Insurgency Attack
Position: Phase Phase
Battalion
Staff
Sleepiness M = 2.39 M = 3.04
sD = 1.14 SD = 1.78
Tense M = 1.70 M 1.65
SD = .53 sD -56
Cheerful M = 2.55 M = 2.46
SD = .71 sD = .90
Relaxed M = 2.33 M = 2.46
SD = .60 SD = .65
Irritable M = 1.36 M = 1.58
SD = .60 SD = .64
Energetic M = 2.21 M = 2.19
SD = .70 SD = .94
Focused M = 2.61 M = 2.50
SD = .66 SD = .86
Jittery M = 1.27 M = 1.54
SD = .63 sD = .71
Dependable M = 2.88 M = 2.73
SD = .42 SD = .72
Efficient M = 2.58 M = 2.50
SD = .66 SD = .81
Sluggish M = 1.73 M = 1.96
SD = .45 SD = .87



Table B-2
Changes in Mood Ratings Across Phases: XO
Staff Insurgency Attack
Position: Phase Phase
xO
Sleepiness M = 2.71 M = 4.00
SD = 1.25 SD = 1.83
Tense M= 1.71
SD = .49
Cheerful M = 2.57
sp = .53
Relaxed M = 2.14
SD = .38
Irritable M = 1.00 M = 1.00
SD = 0.00 SD = 0.00
Energetic M = 2.14 M = 1.75
SD = .69 SD = .96
Focused M = 2.29 M = 2.50
SD = .76 SD = 1.00
Jittery * M = 1.00 M = 1.75
SD = 0.00 sD = .50
Dependable M = 2.57 M = 2.25
sD = .53 SD = .50
Efficient M = 2.14 M = 2.00
SD = .38 SD = .82
Sluggish M = 2.00 M = 1.75
SD = 0.00 SD = .96
* p = .002
B-2



SYNWORK| training and testing took place in a room adjacent to the TOC. Staff
members trained individually. One of the staff members was recruited to serve as task
monitor to ensure that all subjects were progressing satisfactorily in their training and
completed the agreed number of trials (twenty 5 minute SYNWORK! sessions) prior to the
start of the rotation.

Initially, staff members were exposed to each of the four SYNWORK1 component
tasks separately for a two-minute time period. After each component task had been presented
separately, subjects were then presented with a two-minute version of SYNWORK1 with all
tasks occurring simultaneously. This initial session took about 15 minutes to complete.
Following this session, all train-up and experimental sessions were run for five minutes (with
all four SYNWORK1 tasks occurring simultaneously).

The staff members were to complete one sleepiness-mood inventory and at least one
SYNWORK! session each day during the rotation. The sleepiness-mood inventory took
approximately 2-3 minutes to complete.

One day prior to the start of the rotation, researchers distributed the activity monitors
to the subjects. Subjects were monitored for 16 days which were broken into two phases:
Insurgency (10 days), and Attack (6 days). On day 16, the activity monitors were collected
from the subjects. Each subject then completed the Work Load Questionnaire.

Results

OPFOR Sleep History

Questionnaire responses from OPFOR battalion staff members indicated that they slept,
on the average, 6 hours 36 minutes per night (SD = 52.6 minutes) when not on rotation.
Sleep periods ranged from 5-8 hours. Staff members were asked to list the times of the day
they felt most alert and those times they felt most sleepy. They were allowed to list no more
than two separate times for alertness and sleepiness. From a relative standpoint, staff
members were far less variable in their alertness estimates than with their sleepiness estimates.
Standard deviations for sleepiness estimates were 2.4 to 3.4 times higher than those for the
alertness estimates. In general, staff members tended to be most alert from approximately
0735-1035 and from 1510-1735. Staff members were most sleepy from approximately
1015-1135 and from 1405-1450. Sleepiness-alertness ratings followed a general cyclical
pattern.

Eighty percent of the staff felt that they could use more sleep. Most staff members
(80%) felt unrested after awakening. Eighty percent never or almost never take naps when
not on rotation. On the average, staff members indicated that they could use an extra hour
and 50 minutes sleep per day (SD = 23.4 minutes). Nap times ranged from 1 hour - 2 hours
and 12 minutes.



Hours Slept

10

Rotation Sleep Optimal Sleep Off-Rotation Sleep
(Bn Staff Average) (M=8.07h) (SD=.77h) (M=6.6h) (SD=.87h)

Bp eee ee eee ee ee ee eee eee eee:

3 i 1 L 1 il L L i L L il 1 i 1 1 i
1 2 3 4 5 6 7 8 9 10 11 #12 13 #14 #15 16
Day
Figure 1. Average Time Slept by Battalion Staff vs Actual Sleep Requirements.

The staff averaged almost three hours less sleep (5.16 hours or 309.4 minutes) per day
on rotation than what they indicated they needed for total or optimum recovery (8.07 hours or
484.2 minutes per day). Average off-rotation sleep periods were almost 90 minutes (396
minutes sleep per day) less than the stated optimum (See Figure 1).

Total sleep time: Individual trends. From an absolute standpoint, certain staff
positions (XO, S3-Plans, $2), at least in this sample, received very little sleep across phases.
Average sleep times ranged from 4.4 hours to 4.6 hours during the Insurgency phase. During
the Attack phase sleep times ranged from an average of 3.7 hours to 4.5 hours sleep per day
for these individuals (See Tables | and 2).



REPORT DOCUMENTATION PAGE

1. REPORT DATE 2. REPORT TYPE 3. DATES COVERED (from. . . to)
1996, May Final December 1994-February 1995
4, TITLE AND SUBTITLE 5a. CONTRACT OR GRANT NUMBER
Characterization of Sleep, Mood, and Performance Patterns in Sp. PROGRAM ELEMENT NUMBER
Battalion Staff Members at the Joint Readiness Training Center 0603007A.
6. AUTHOR(S) 5c. PROJECT NUMBER

A793
Robert J. Pleban and Tina L. Mason 5d. TASK NUMBER

2127

Se. WORK UNIT NUMBER

HO1
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER
U.S. Army Research Institute for the Behavioral and Social Sciences
ATTN: PERI-IJ
5001 Eisenhower Avenue
Alexandria, VA 22333-5600
9, SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. MONITOR ACRONYM
U.S. Army Research Institute for the Behavioral and Social Sciences ARI
5001 Eisenhower Avenue
Alexandria, VA 22333-5600 41. MONITOR REPORT NUMBER

Research Report 1693

12. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES

14, ABSTRACT (Maximum 200 words):

‘This research tracked the sleep/work pattems of 10 members of a battalion staff during a low-intensity conflict scenario. Sleep patterns were captured
by wrist-wom activity monitors that permitted minute-by-minute assessment of the activity levels of each staff member. Staff members were
monitored over a 16-day rotation. Data on sleep habits and perceptions of work load levels were collected using paper-and-pencil questionnaires.
Daily estimates of cognitive work capacity were obtained using a computerized synthetic work task. In addition, a brief computerized sleepiness-mood
scale was presented each day. Staff members slept, on the average, 5.2 hours (range 3.5-6.4 hours) per day. The staff averaged almost 3 hours less
sleep per day on rotation than what they indicated they needed for total recovery (8.1 hours sleep per day). Certain staff positions (XO, S2, and S3-
Plans) received very little sleep across the rotation (3.7-4.6 hours sleep per day). Over 60 percent of the sleep obtained was fragmented in nature
(sleep periods of 10 minutes or less). Substantial increases in response variability were noted for one staff member. This preliminary research,
together with observations from the combat training centers, suggests that to effectively sustain staff performance during continuous operations, better
utilization of staff resources is critical. In addition, commanders must take an active role in the development of unit sleep/work management plans.
This includes educating unit members on the importance of sleep in combat operations and how to optimize the recuperative value of available sleep
periods through specifically tailored unit sleep plans.

15. SUBJECT TERMS.

Continuous operations —_ Cognitive work load Battalion staff work load
Sleep/work plans Sleep management
_ SECURITY CLASSIFICATION OF || 19. LIMITATIONOF | 20. NUMBER | 21. RESPONSIBLE PERSON
ABSTRACT OF PAGES (Name and Telephone Number)

16. REPORT 17. ABSTRACT | 18. THIS PAGE
Unclassified | Unclassified | Unclassified | Unlimited 51



Minutes Slept

Percentage

700

600

500

b
i=}
ro}

300

200

100

120
110
100
90
80
70
60
50
40
30
20

10

leep Off-Rotation Sleep

Rotation Sleep Opti

1 2 3 4 5 6 7 8 9 10 11 #12 #13 #14 #«~15 16
Day

Figure A-9. Comparison of Rotation Sleep vs Individual Sleep Requirements - XO.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
oe —

Day
Figure A-10. Quality of Sleep by Day - XO.

A-5



Table 7

SYNWORK1 Performance Trends Across Phases: S3-Plans

Staff Insurgency Attack Phase
Position: Phase Sessions = 6
S3-Plans Sessions = 3
Composite M = 479.3 M = 551.5
Score SD = 16.2 SD = 94.1
Sternberg M = 86.7 M = 116.7
Memory SD = 37.8 SD = 39.3
Arithmetic M = 163.3 M = 220
SD = 25.2 SD = 46.9
Visual M = 139.3 M = 131.5
Monitoring SD = 3.8 SD = 14.0
Auditory M = 90.0 M = 83.3
Monitoring SD = 10.0 SD = 26.6
Table 8
SYNWORK1 Performance Trends Across Phases: XO
Staff Insurgency Attack Phase
Position: Phase Sessions = 4
xO Sessions = 8
Composite M = 699.1 M = 715.0
Score SD = 109.1 SD = 63.7
Sternberg M = 135.0 M = 125.0
Memory SD = 17.7 SD = 37.8
Arithmetic M = 326.3 M = 347.5
SD = 83.8 sp = 41.1
Visual M = 132.9 M = 137.5
Monitoring * SD = 10.0 SD = 2.1
Auditory M = 105.0 M = 105.0
Monitoring SD = 20.7 sp = 19.1
* P< .05

18



U.S. ARMY RESEARCH INSTITUTE
FOR THE BEHAVIORAL AND SOCIAL SCIENCES

A Field Operating Agency Under the Jurisdiction
of the Deputy Chief of Staff for Personnel

EDGAR M. JOHNSON
Director

Technical review by

David M. Penetar
Patrick J. Valentine

NOTICES

DISTRIBUTION: Primary distribution of this report has been made by ARI. Please address correspondence
concerning distribution of reports to: U.S. Army Research Institute for the Behavioral and Social Sciences,
ATIN: PERI-STP, 5001 Eisenhower Ave., Alexandria, Virginia 22333-5600.

FINAL DISPOSITION: This report may be destroyed when it is no longer needed. Please do not return it to
the U.S. Army Research Institute for the Behavioral and Social Sciences.

NOTE: The findings in this report are not to be construed as an official Department of the Army position,
unless so designated by other authorized documents.



17. In addition to your primary sleep periods, how often, on the average, do you catnap during a
rotation?

1 or 2 times per week during a rotation

3 or 4 times per week during a rotation

5 or more times per week during a rotation
More than once a day during a rotation

18. If you nap, generally how long are these naps?

19. How many cups of coffee do you drink per 24 hours?. . Other caffeinated drinks, e.g.,

Coke, Pepsi?. cans per 24 hours.

20. How many cigarettes do you smoke per 24 hours?

None
Less than 1 pack
1 pack
2 packs
More than 2 packs per day

21. Do you use smokeless tobacco? Yes No



Minutes Slept

Percentage

700

600

500

400

300

200

100

120
110
100
90
80
70
60
50
40
30
20

10

GRAPHIC SUMMARY OF INDIVIDUAL CHANGES IN SLEEP DURATION AND
SLEEP QUALITY BY DAY

Rotation Sieen Opti

Sleep Off-Rotation Sleep

Day

Figure A-1. Comparison of Rotation Sleep vs Individual Sleep Requirements - S1.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min or Less)
“ —_

Figure A-2. Quality of Sleep by Day - S1.

A-l



700

600

500

Minutes Slept
-
°
°

300

200

100

130
120
110
100

90

Percentage

Rotation Sleep
Optimal Sleep

Off-Rotation Sleep

Day

Figure A-19. Comparison of Rotation Sleep vs Individ. Sleep Requirements - ADO.

Movement Fragmentation
(% Restless Sleep) (% Sleep Pds. 10 Min. or Less)
—oe— —_

Day
Figure A-20. Quality of Sleep by Day - ADO.

A-10

Po



useful. For example, one item on the Sleep History Questionnaire focused on identifying
peak alertness times for staff members. As was noted earlier, distinct alertness and sleepiness
periods can be identified. Again, this background information can be useful in planning
sleep-work schedules, and may be useful in prioritizing certain tasks or activities.

Performance and Mood Changes Over Time

The poor quality sleep obtained by the staff members did not seem to affect
performance as assessed by the SYNWORK| task. While the SYNWORK1 performance data
did not conclusively show any associated decrements in cognitive performance, there is ample
research showing that increasing sleep loss does lead to degraded performance (See FM 22-9
for a brief summary of the varied effects of sleep loss).

As can be seen from Table 7, the S3-Plans’ overall mean composite score, while
improving over time, became increasingly variable over phases. In contrast, the variability in
the mean composite scores of the other staff members either decreased substantially or
remained relatively consistent over time. Although the XO and FSO were some of the more
sleep deprived staff members, along with the S3-Plans, the data point again to the importance
of individual differences in adapting to sleep loss. While it may appear, at first, that the S3-
Plans’ performance was consistent with the two other similarly sleep deprived staff members,
the increased variability in responding on the $3-Plans’ part, suggests otherwise and is
consistent with how performance degrades in such situations.

In general, relying on the average score obtained on a task over time as indicative of
performance capability can be misleading. As F. W. Hegge and T. F. Elsmore (personal
commmunication, July 29, 1994) note, signs of performance impairment in continuous
operations are revealed more in lapses in performance and increased variability in responding
by the individual. These individuals believe that by focusing only on mean differences,
particularly at the group level, important changes occurring within the individual may be
masked. In an operational setting, predictability of individual performance is critical.
Commanders need to know who is at risk, at which time(s), and for how long.

For tasks such as SYNWORK1 to be more informative, adequate train-up time and
multiple assessments (3-4) per day at specific time intervals (to detect circadian effects and
more completely assess individual variability in responsiveness) are required. Although this
was the intent, once the researchers left the TOC site, and the preparation/activities for the
rotation became more intense, SYNWORK sessions dropped almost to zero for many staff
members. Once the rotation started, participation on the SYNWORK1 task was haphazard.
Similarly, mood also needs to be consistently measured at multiple times throughout the day.
Only then will it be possible to accurately detect and assess the key indicators of performance
impairment as noted earlier by Hegge and Elsmore (1994).

21



The first task, the Sternberg Memory Task, appears in the upper left quadrant of the
PC screen. For each session a list of six letters ("positive list") is chosen from the alphabet
and displayed in upper case letters in a box at the top of the quadrant. The positive list is
displayed for only 5 seconds, after which it is replaced by the words "RETRIEVE LIST".
When this message is displayed, clicking the mouse on the list box results in the display of
the list for another 5 seconds. A point penalty (10) is assessed for each list retrieval. An
equal-sized list (‘the negative list") is also selected at the start of each session. Following
each inter-trial interval (20 seconds), a sample letter is displayed in the box in the center of
the quadrant. The individual’s task is to indicate, by clicking the mouse on either the YES or
the NO box at the bottom of the window, whether the letter is a member of the positive list
or not. The sample disappears as soon as either a correct response or error is made. Points
(10) are awarded for each correct response and deducted (10) for each error.

An Arithmetic Task is presented in the upper right quadrant. The task consists of
adding two or three randomly selected numbers less than 1000. The individual’s task is to
calculate the answer by clicking on "+" and "-" boxes below each character of the answer,
which is initially set to "0000". Clicking on a box labeled DONE at the bottom of the
window results in the presentation of a new problem, addition of points (10) for correct
answers, and deduction of points (10) for errors. There are no time limits for completion of
this task.

The lower left quadrant contains the Visual Monitoring Task. In this task a pointer
moves from the center of a 200-pixel scale towards either end at a constant rate of 5 pixels
per second. Clicking the mouse on a box labeled RESET at the top of the window resets the
pointer to the center. The individual’s task is to prevent the pointer from reaching the end of
the scale. Points are awarded for each reset according to a pre-set formula. The default
maximum point value is 10. The closer the pointer is to the end of the scale at reset, the
more points are awarded. Points (10) are deducted when the pointer reaches the end of the
scale and remains there for one second, and additional points (10) are deducted each second
the pointer stays at the end of the scale. Unlike the previous tasks, response omissions for the
visual monitoring task are severely penalized.

In the lower right quadrant is the Auditory Monitoring Task. At periodic 5 second
intervals a brief tone is sounded over the PC Speaker or over the headphones. The tone is
either of two frequencies, low (931 Hz) or high (1234 Hz). The individual’s task is to click
the mouse in a box at the top of the window labeled HIGH SOUND REPORT following a
high tone. High tones occur on 20% of the trials. Correct responses are those that occur
following a high tone, prior to the next scheduled tone. All other responses are incorrect.
Points are awarded (10) for each correct response, and deducted (10) for each error.

The SYNWORK1 program requires an IBM-compatible personal computer, a
Microsoft-compatible mouse, and an EGA or better display. See Elsmore (1994) for
additional details. For this study, SYNWORK1 was run on an IBM compatible 80386



OPFOR WORK LOAD QUESTIONNAIRE

SSN (last 4). Duty position,

4. How long have you served in this unit? months.

2. How long have served in your current duty position in this unit? months.
3. How many rotations have you participated in over the past year with this unit?

4. How many days does it take before you begin to feel fully recovered from the effects of a
rotation?,

5. Should there be more recovery time between rotations? Yes No. If yes, how much
time is needed and why?

6. As the rotation progresses, do you change any of your work habits to compensate for increasing
fatigue/stress levels? Yes No. If yes, please describe.

7. \s your current work load excessive? Yes No. If yes, what can be done to lighten
your work load?

8. Does the OPFOR TOC have a formal sleep management plan?
Yes No. If yes, please describe the plan.

9. Is this plan adequate? Yes No. If no, what modifications are needed?



During the rotation, staff members average, based on self-reports, 6 hours and 7
minutes sleep per day (SD = 73.2 minutes). Primary sleep periods are, for the most part,
planned. There is a TOC shift schedule that is based on 12 hour day and night shifts in
which no one does a shift without being off for at least 11 hours prior to the start of their
shift, But, as one staff member noted, the emphasis is less on sleep management and more on
time management. Napping during rotation is infrequent. Eighty percent of the staff
indicated that they napped only 1-2 times per week while on rotation. Naps, when taken,
averaged 44.4 minutes (SD = 19.2 minutes). The duration of these naps ranged from 18-60

minutes.

The use of stimulants, in the form of caffeine and nicotine, was reported. Staff
members consumed approximately 3 cups/cans of coffee and/or other caffeinated beverages
(soft drinks) per 24 hours during a rotation. At approximately 100 mg caffeine per cup of
coffee and 50 mg caffeine per soft drink, staff members consumed roughly 250 mg of
caffeine per day. This does not include any extra caffeine which may be present in certain
headache pain products as buffering agents. Single dosages of from 300-600mg of caffeine
are recommended for maintaining alertness in continuous operations (Belenky et al., 1994).
Although no staff member smoked, 20% did use smokeless tobacco.

Characterization of Actual Sleep Periods

Total sleep time: Staff trends. The staff averaged 5.2 hours (SD = 1.9 hours) sleep
per day. During the Insurgency phase, the battalion staff averaged, as a whole, 5.3 hours
(SD = 1.9 hours) sleep per day. Sleep times ranged from 3.9 hours (Day 10) to 6.4 hours
(Day 6). For the Attack phase, the staff averaged 4.9 hours (SD = 1.9 hours) sleep per day.
Sleep times ranged from 3.5 hours (Day 16) to 6.2 hours (Day 14) during this phase (See
Figure 1). Differences between phases were not statistically significant [t(7) = .359, n.s.]