Taste 4.—Mean Psychomotor Performance Scores

Group-I Group IL Group III

Day = ‘Time Score Day ‘Time —- Score Day ‘Time —Score
0700 629 0700 545 0700 646

1 1000 641 1 1000 608 1 1000 681
1400 647 1400 562 1400669

1900 655 1900 542 1900. _691

X 643, x 564 672

0700 663 0700 562 0700 660

2 1000 658 2 1000 597 2 1000 696
1400 631 1400 597 1400 678

1900 665 1900, _615 1900 692

x 654 x 593 x 682

0700 671 0700 591 0700-696

3 1000 695 3 1000 635 3 1000 726
1400 695 1400 627 1400 715

1900 695 1900 653 1900 733

x 689 ¥ 627 x 718

0700 666 1300 622 0100 731

5 1000 688 5 1600 666 5 0400 693
1400 691 2000 674 0800 604

1900 690 0100 666 1300 702

x 684 x 657 X 683

0700 681 1300 652 0100 mu

6 1000 690 6 1600 683 6 0400 728
1400 692 2000 676 0800 643

1900 689 0100 676 1300 732

x 688 x 672 704

0700 688 1300 660 0100 759

1 1000 693 7 1600 699 7 0400 751
1400 704 2000 685 0800 745

1900 713 0100 691 1300 736

x 700 x 684 X 748
0700-699 1300-680 0100 782

8 1000 708 8 1600 673 8 0400 753
1400 689 2000 681 0800 703

1900 709 0100 683 1300 715

x 701 x 679 x 738

0700 697 1300 670 0100 756

1000 724 9 1600 676 9 0400 766

° 1400 715 2000 719 0800 727
1900 _722 0100 _689_ 1300, 725

x 714 x 689 x 744

0700 737 1300 710 0100 742

10 1000 733 10 1600 700 ro (0400 717
1400 741 2000 723 0800 751
1900 _735_ ~0100_ _689_ 1300, 743.

x 737 x 706 x 753

0700 729 1300 693 0100 737

1000 755 1 1600 729 11-0400 m1
M400 753 2000724 0800773
1900, 773 2100, 701 1300, 176

x 753 Xx 712 x 762

16


RECTAL TEMPERATURE SUMMATION DIALS
0030

A Indicates end of

control period.
GROUP 1 Pert

Ficure 9.—Rectal temperature summation dials for Group IT.

RECTAL TEMPERATURE SUMMATION DIALS
0030

2130 0330

1830 0630
= 2 in 3
1530 0930

1230

ao ~ 5
Indicates end of
i r
control period. GROUP IT

Ficure 10.—Rectal temperature summation dials for Group III.

10


our drawing unequivocal conclusions about the
performance effects of the experimental manipu-
lation of the time variable. However, it does
seem clear that the performance of the “west-
bound” group did not reflect adaptation to the
new time schedule, and, although it is much less
clear, it also seems likely that the “eastbound”
group did not adapt in the course of the study.

Overall, the multiple-task-performance data
on the one hand and the physiological and bio-
chemical data on the other lead to different
conclusions about the adaptation of the subjects
to the two different time shifts. We can offer
no explanation for this discrepancy; apparently,
different processes are involved as higher order
determinants in the two spheres of measurements.

V. Conclusions.

Because of the small sample number and the
wide individual variability in this study, it is
difficult to draw definitive conclusions.

According to the physiological and biochemi-
cal measurements there is little difference be-
tween the two 6-h-change groups, both of which
required longer rephasal times than did the
group with sleep loss but no time change.

The psychomotor performance test indicates
the greatest change in the group with the day
shortened by 6 h.

The complex performance task (MTPB) indi-
cates the greatest deficit in performance for the
group with the day shortened (west to east) by
6 h and the best postshift performance by the
group whose day was lengthened (east to west)
by 6h, Therefore, if performance of the type
represented by the MTPB is the most important
consideration, then travel from west. to east (or
“quick turnarounds” for shift workers) appears
to be more deleterious than the opposite occur-
rences. However, this cannot be predicted on
the basis of the physiological and biochemical
determinations made in this study.

REFERENCES

a

Chiles, W. D., A. B. Jennings, and G. West: Multiple
‘Task Performance as a Predictor of the Potential
of Air Traffic Controller Trainees. FAA Office of
Aviation Medicine Report No. AM~72-5, 1972.

. Elliott, A. L., J. N. Mills, D. S. Minors, ‘and J. M.
Waterhouse: The Effect of Real and Simulated
Time-Zone Shifts Upon the Circadian Rhythms of
Body Temperature, Plasma — 11-Hydroxycortico-
steroids, and Renal Excretion in Human Subjects,
J. PHYSIO: 221 :227-257, 1972.

Few, J. D.: A Method for the Analysis of Urinary
1T-Hydroxycorticosteroids, J. ENDOCRINOL,, 22 :31~
46, 1961.

. Fiorlea, V., and R. Moses: Automated Differential
Fluorometric Analysis of Norepinephrine and Epine-
phrine in Blood Plasma and Urine, BIOCHEM.
MED., 5 :483-504, 1971.

Hetherington, N. W., C. M. Winget, L. S. Rosenblatt,
and P. B. Mack: The Summation Dial, a Vectorial
Representation of ‘Time Series Data, J. INTER-
DISCIP. CYCLE RES., 2:365-877, 1971.

Higgins, E. A, W. D. Chiles, J. M. McKenzie, P. F.
Iampietro, C. M. Winget, G. E. Funkhouser, M. J.
Burr, J. A. Vaughan, and A. E. Jennings: The
Effects of a 12-Hour Shift in the Wake-Sleep Cycle
on Physiological and Biochemical Responses and

i

3.

Pp

20

Multiple Task Performance. FAA Office of Aviation

Medicine Report No. FAA-AM-75-10, 1975.
7. Klein, K. E., H. M. Wegmann, G. Athanassenas, H.
Hohlweck, and P. Kuklinski: Air Operations and
Circadian Performance Rhythms, AVIAT. SPACE
ENVIRON. MED., 47(3) :221-230, 1976.
Klein, K. E., H. M. Wegmann, and B. I. Hunt:
Desynchronization of Body ‘Temperature and Per-
formance Circadian Rhythms as a Result of Out-
going and Homegoing Transmeridian Flights, AERO-
SPACE MED., 48 :119-132, 1972.
. Lindquist, E. F., Design and Analysis of Buxperi-
ments in Psychology and Rducation, Houghton Mit-
flin Co,, Boston, 1958, p. 292,
Pearson, R. G., and G. E. Byars, Jr.: The Develop-
ment and Validation of a Checklist for Measuring
Subjective Fatigue. USAF School of Aerospace
Medicine Report No, TR-56~-115, 1956,
Saldivar, J. 'T.: Simplified Technique for Applica-
tion of Dry ECG Electrode, AEROSPACE MED.,
42 456-457, 1970.
Wegmann, H. M., H. Bruner, D. Jovy, K. H. Klein,
J. P. Marbarger, and A. Rimpler: Effect of Trans-
meridian Flights on the Diurnal Excretion Pattern
of 17-Hydroxycorticosteroids, AEROSPACE MED.,
41(9) 1003-1005, 1970.

10,

nn.

12.



PHYSIOLOGICAL, BIOCHEMICAL, AND MULTIPLE-TASK-PERFORMANCE
RESPONSES TO DIFFERENT ALTERATIONS OF THE WAKE-SLEEP CYCLE

I. Introduction.

Because rapid air transportation across time
zones often necessitates a change in the traveler’s
wake-sleep cycle that consequently results in dis-
ruption of his biological rhythm patterns, and
because rotating shift patterns are necessary to
maintain 24-h service in many areas, the FAA
has continued its interest in biorhythms, their
changes as a result of altering the wake-sleep
cycle, and their relationships with performance.

II. Material and Methods.

We previously conducted a study in which the
wake-sleep cycle was altered by 12 h& This
current study was conducted in three phases.
Three groups, each comprising five healthy, male,
paid volunteers (ages 21 to 30), were studied in
a laboratory setting. Because results of the 12-h
study indicated that some of the effects seen were
due to the long period of confinement in the
laboratory, the data collection periods for this
study were shortened to the minimum number
of days consistent with obtaining the desired
results. Each group first spent five 10-h days
training on a psychomotor performance test
(Kugelmaschine) and the CAMI Multiple Task
Performance Battery (MTPB); a total of 15 h
of training was given on the MTPB. This
training period, which also provided an oppor-
tunity for subjects to become familiar with the
laboratory setting and learn the experimental
protocol, was followed by an 11-day data collec-
tion period. Baseline data were collected for 3
days, during which subjects adhered to a day/
night routine; ic., sleeping from 2230 to 0600.
On the fourth day each group took a “flight” in
the CAMI altitude chamber; time spent aboard
was equivalent to that required for a flight from
Oklahoma City to London with a change of
planes at Chicago’s O’Hare International Air-
port. Subjects in the first group (Group I)
slept from only 0230 to 0600 on the fourth night

and .then returned to their former day/night
routine, sleeping from 2230 to 0600 for the re-
maining 7 days. The next group of subjects
(Group II) had their day extended by 6 h and
began a new routine of sleeping from 0430 to
1200; they followed this new routine for 7 days.
This is the timeframe that would be assumed
after an east-to-west flight across six time zones.
On the fourth day subjects in the last group
(Group III) slept from 2030 to 2400 only and
the following 7 days slept from 1630 to 2400;
this routine compressed their day and established
a new wake-sleep cycle that was 6 h earlier than
the usual cycle. This timeframe corresponds to
the timeframe following a west-to-east flight
across six time zones.

Measurement of heart tate (HR) and internal
body temperature (T,-) were made hourly
throughout the study. Dry silver electrodes’
attached in the CM; position were connected by
wires to an Avionics Electrocardiocorder, and
HR responses were recorded on electromagnetic
tape. Tape and batteries were replaced each
24h. Although HR was recorded continuously,
only hourly average readings were statistically
analyzed. Internal body temperature was meas-
ured with a thermistor probe inserted 10 cm
beyond the anal sphineter. Values were read to
the nearest 0.1°C with a portable bridge.

Urine was collected every 4 h throughout the
experimental period. The volume was recorded ;
aliquots were taken, preserved with 12N HC1,
and frozen for later biochemical analyses. Uri-
nary catecholamines‘ and 17-ketogenic steroids*
(17-KGS) were determined by using Technicon
Autoanalyzer systems. Sodium (Na‘) and po-
tassium (K*) were measured with an atomic
absorption-emission spectrophotometer (Instru-
mentation Laboratory, Inc., Model 353).

Subjective questionnaires included the 10-item
Subjective Fatigue Checklist developed by Pear-



800 GROUP I
~ re
700 r poo
sof ~ 5
sool muy ney my Sb RH BM HA KA BAY RL
, $88 888 888 3 888 838 $38 338 333 883 838
S58 ERS Fes SF Sse See Sek Sse ose Ste Sse
w
Z s00 Group I
°
® 100 a pene KAR
a TK r :
BS soolmy wy me BBY RM ba A Pree)
z “gag gag ggg 5 S88 S98 298 382 388 G82 E88
800 GROUP IL
v Nn \ AA
Tor yw . V V
600 &
sool my mH KH FRM RH BA HA med MAL BM
388 398 38g 5 898 $83 388 838 838 833 $38
a8 538 S82 F S88 582 382 582 O87 os? 38"

TIME (CLOCKHOURS)

Ficure 21—Mean Psychomotor Performance scores as a
function of time of day for Groups I, U, and UT
(n=5 for each group).

ference between groups was in the preshift data;
this result is clearly an artifact of the reduction
of the between-subjects variance to essentially
zero for the preshift phase caused by the method
of computing the composite scores. For all
three phases of the experiment, the sessions effect
and the interaction of sessions and groups were
significant at the .01 level of confidence. The
sessions x periods and the sessions x periods x
groups interactions were significant in the two
postshift 3-day blocks (p<.01). The periods
effect. was significant for the preshift (p<.01)
and the Days 8-10 blocks (p<.05), and the
periods x groups interaction was significant for
the first postshift block (p<.01). The general
picture that emerges from examination of the
figures is that on the average, Group IT (east-
west) was least affected by the shift; in fact,
throughout the study, performance was arith-
metically better maintained by Group II than
by the control group. Because of the significant
triple interaction for both the postshift blocks,
interpretation of the sessions x groups interac-
tion is difficult; however, the daily pattern of
changes over sessions generally was different for
the three groups. On the average, the perform-
ance of Groups I and III declined over the

MULTIPLE TASK PERFORMANCE BATTERY

Lu 540 Days 1-3 (Control period) Days 5-7 (First 3 days postshift) Days 8-10 (Second 3 days postshift)

&

S 520

2 500 =

Ww 480

460

E440 —

B 420 e—© Group I

a 400 o—o Group IL

3S 380 +— Group IL

Oo 360

cop G22ee8eeeisig? GELSERCSELERE! PLSELTEETERE EE

croupm 22888888888 2S2 LLPELEERESLE2 EFLETLRPSEEREE
TIME OF DAY (symbols are at beginning of each |-hour test session)

Ficure 22.—Multiple Task Performance Battery mean composite performance scores as a function of time of test-
ing for Groups I, II, and III, for the control period, the first 3 days postshift and the second 8 days postshift

(n=5 for each group).

17



sleep obtained in early morning hours, when
activity levels are normally reduced.

In any event, the results of the physiological
and biochemical measurements in our study do
not correspond to those of time zone displace-
ment studies; they do indicate that perhaps the
change in the wake-sleep cycle experienced by a
shift worker does not have the same effect on
physiological responses as the change experienced
by a traveler who is displaced to a new time zone.

Psychomotor Performance. Psychomotor per-
formance gave a greater indication of differences
between Groups II and TI than did the phys-
iological and biochemical measurements. Group
Il’s performance was similar to that of the con-
trol group (Group I) the first day after the
change in the wake-sleep cycle in that the poor-
est performance of the day was the first test
after awakening from the sleep period. It was
not until the last 2 days that Group TIT showed
its poorest performance the first period after
awakening. Although the sleep surveys yielded
no indication, perhaps the quality of sleep ob-
tained by Group IIT was not equivalent to that
of Group IT.

Multiple Task Performance Battery. The in-
terpretation of the effects of the time shift on
multiple task performance must be conditioned
by two factors. First, the subjects in Group IT
were permitted a sleep period of normal dura-
tion immediately prior to the postshift phase of
the study, whereas the subjects of Groups I and
III had short (314-h) sleep periods prior to the
shift. Second, discussions with the subjects
strongly suggested that most of them considered
themselves to be “night people”; thus, a shift
west would be more like their normal schedule
and a shift east would be further from their
normal schedules than would appear simply on
the basis of clock time.

The preshift performance curves are about
typical of what would be expected, although the
magnitude of the fluctuations was greater for
Groups II and III than for Group I. Generally,
the subjects showed declining performance dur-
ing the morning hours, reached a low point after
the lunch break, and showed relatively high
levels of performance during the late afternoon
and early evening performance sessions.

During the 3-day block immediately following
the shift, Groups I and III showed similar per-

19

formance curves that could be described in part
as exaggerations of their preshift performance.
The main difference is seen in the pronounced
drop in performance during the final 2 hours of
the day. The results for these two groups are
probably most. parsimoniously explained as re-
flecting a residual effect of the loss of sleep ex-
perienced prior to the shift. During this same
period, the performance of Group II could be
described as reflecting directly the 6-h shift in
the day. The performance of these subjects ap-
pears to start the day at about the level main-
tained during the postlunch session of the
preshift block. Their performance improved
somewhat through the day, but they showed a
marked drop in performance at the end of the
day. In this respect, all three groups performed
as though the total period of wakefulness had
been lengthened, with a resultant increase in the
buildup of fatigue.

During the final 3-day block, the performance
of the subjects in the control group returned to
approximately the levels maintained prior to the
shift phase of the experiment. However, there
was an increase in the magnitude of the session-
to-session fluctuations. Group III, the “east-
bound” group, showed the poorest performance
during the 1-h period that began 3 h later (local
time) than the period of lowest performance
during the preshift phase of the experiment, but
the end-of-day depression of performance found
during the first 3 days postshift was not present;
instead, the group’s performance improved rela-
tive to the low point of the curve. Overall, the
performance of this group was the poorest of
the three. The “westbound” group, Group IT,
maintained a fairly stable level of performance
during the first three sessions of the day during
this phase but still exhibited the substantial end-
of-day performance deficit.

The time base for Figure 23 is such that, if
complete adaptation had taken place, the curves
for Groups II and III should have been “identi-
cal” to the curve for Group I. Clearly they are
not, as evidenced by both the curves and by the
signincant sessions x groups interaction. Since
the curve for Group I was approximately of the
same form during the final 38 days that it was
during the preshift phase, it appears that the
effects of the sleep loss on the shift day had been
dissipated. Unfortunately, the possibility that
the same was not true for Group III precludes



NOREPINEPHRINE SUMMATION DIALS

0030
2130 0330
1830 0630
2 3
4 A
1530 0930
1230

I indicates end of
control period.

GROUP II

Ficure 17.—Norepinephrine summation dials for Group III.

!7-KETOGENIC STEROIDS SUMMATION DIALS
0030

2130

1830

4 5 \
vw

A Indicates end of

control period. GROUP IT

Ficure 18.—17-ketogenie steroids summation dials for Group II.

14


HEART RATE SUMMATION DIALS

0030

0330

0630

A Indicates end of
control period.

GROUP I

Ficurr 4.—Heart rate summation dials for Group I.

The times of peak response for HR and T,.
are better defined than those for the urinary
constituents, as the frequency of measurement
was four times greater for these two parameters
than for the urine. The urinary constituents for
Group I, however, did evidence perturbations in
the peak response pattern at Days 4 and 5. The
17-KGS, shown in Figure 6, were chosen as
representative of urinary constituent data for
Group I.

The moderate sleep loss at Day 4 for Group I
did not result in any long-term pattern displace-
ment for time of peak response for any of the
variables studied.

Heart rate made a very rapid adjustment to
new wake-sleep cycles for each of the protocols
studied to date. In the previously reported
12-h-shift study, the mean rephasal time for HR

was 1.4 days. For Groups IT and III, the mean
rephasal time was also 14 days. Heart rate is
the only variable for which the rephasal times
were the same. The summation dials for HR
are shown in Figure 7 for Group IT and in
Figure 8 for Group ITI.

Rectal temperature rephasal occurred in a
mean of 4.9 days for the 12-h group and means
of 2.4 and 2.0 days respectively for Groups II
and III of this study. Figure 9 gives the sum-
mation dials for T,. for Group II and Figure 10
presents the T,, summation dials for Group III.
These two groups demonstrate very similar re-
phasal patterns, although in opposite directions.
Subject 5 of Group IT (Figure 10) suffered from
a severe intestinal upset and diarrhea during the
study, and his patterns are not typical of the
others in the group.


parted to the target, and the subject attempts to
counteract this movement by using his control
stick to keep the dot at the center of the screen
(as defined by two crosshairs scribed on the face
of the screen). The tracking task is scored by
analog circuitry that accumulates integrated
absolute error and integrated error-squared
measures for the horizontal and vertical dimen-
sions. Root-mean-square error is computed from
the error-squared measures, and a vector sum
measure is computed by taking the square root
of the sum of the measures of horizontal and
vertical error squared. The rationale for using
this vector sum score is that the integrated error
measures represent average horizontal and verti-
cal distance from the center of the screen. There-
fore, the vector sum of these distances would
represent the hypotenuse of the triangle defined
by these horizontal and vertical distances.

In the analyses performed on the MTPB data,
the measure used was an equal-variance com-
posite score that was computed as follows: For
each measure, an appropriate equation was de-
rived by using the data for the 3 days prior to
the shift. The equation was developed in a
manner such that the mean score for each sub-
ject was 500 with a standard deviation of 100
for those 3 days combined ‘(time scores were
“reflected” so that a larger score meant better
performance). The raw scores for a given
measure taken during the postshift phase of the
experiment were entered into the associated
equation to get a derived measure, and the de-
rived measures were then combined across tasks.
The resultant composite score gave equal weight
to each of the original measures. The com-
posites also tended to equalize the three groups
as regards the initial values of the scores. Hence,
the interpretation of the scores is properly made
in relation to the 8 days prior to the shift.

The Kugel test estimated psychomotor per-
formance. The “Kugelmaschine” was a hori-
zontal rotating cylinder containing a row of five
holes of graded sizes. Three sets of five steel
balls corresponding in size to the holes in the
cylinder were placed in a tray attached to the
machine near the base of the cylinder. The test
subject, seated in front of the tray, was instructed
to pick up and insert as rapidly as possible the
correct ball into a corresponding row of station-
ary holes lined up with those of the rotating
cylinder. The cylinder rotated at 80 holes per

min. Each test session was 10 min in duration
for a total possible score of 800. Each correct
selection was recorded on an attached counter.
A schedule of events showing the time and
frequency of occurrence is presented in Figure 1.

SCHEDULE OF EVENTS

GRouP GROUP GROUP
I rw
C + — 2400 -p Arise, Urine, Fatigue Checklist
0600 F 1200-F 2400 T sicep' survey, Breakfast, Clean Up
Kugel
Eosoo + 1400+ 0200 49
4 MTPB
t 1000 -+ 1600 + 0400 + — Urine, Fatigue Checklist
~ Kiigel
2 1200+ 18004 0600 4 burn
5 F 4 MTPB
© [1400+ 2000-4 0800 +— Urine, Fatigue Checklist
4 Kagel
F 1600-4 2200+ 1000
s mTPeB
b 4 4 rine, Fatigue Checklist
Sf 1e00f 24004 1200 tespary Urine, Fatigue Chechtis
_ t Kugel
D [2000+ 0200 + 1400 +“
= MTPB
L 2200+ 0400+ 1600 Urine, Fatigue Checklist
my f
= fes00t 06004 18004 S$
FE 4 L
-oz00+ os00+ 20004 ¢ fF Urine
=
F o400+ 1000+ 2200 +
E 7 P
Losoot 1200+ 2400

MTPB= Multiple Task
Performance Battery

Fioure 1.—Schedule of events.

All groups followed the schedule shown for
Group I during the first 8 days of the experi-
ment. Each group followed the schedule as
indicated by group number for the last 7 days
of data collection.

III. Results.

Subjective Forms. Figure 2 presents a bar
graph for the three groups, indicating the per-
centage of the sleep periods they were asleep.
Table 2 presents the sleep data as it pertains to
the quality of sleep. For each group is presented
the total time asleep (percentage), the percent-
age of the sleep period spent in moderate or
deep sleep, and the percentage of the sleep period
spent awake or in light sleep. During the con-
trol period (night sleep), Group I slept 81.3
percent of the time available, Group IT slept
85.6 percent of their sleep periods, and Group



son and Byars" and a sleep survey developed at
the USAF School of Aerospace Medicine that
reflected the test subjects’ judgment of both the
length and quality of sleep the previous night.
Subjects were tested on the CAMI MTPB at
4-h intervals in 2-h sessions; both the first and
second h of a session involved the task schedule
shown in Table 1. The MTPB consists of five

Taste 1—One-Hour Task Schedule for All

Groups
Time in Minutes

O-15 15-30. 30-45 45-60
Lights Monitoring x x x x
Meter Monitoring x x x x
Arithmetic x x
Pattern Identification x
Problem Solving x x
Tracking x x

subject panels and the associated programing
and scoring circuitry. Each panel contains the
displays and response devices for six different
tasks, each of which may be presented in isola-
tion or in any combination of tasks. The tasks
are described in more detail elsewhere; there-
fore, only a brief description of each will be
given here.

Warning Lights. The warning lights task in-
volves monitoring of five green lights and five
red lights. Under each light is a pushbutton
switch. The green lights are normally on and
the red lights are normally off; the subject is
instructed to push the button under the light
whenever a light changes state. Signals were
introduced at random intervals with a mean
intersignal interval of 30 s.

Meter Monitoring. The meter monitoring
task involves monitoring of four meters mounted
across the top of the subject panel. Normally,
the meter pointers are moving at random around
a mean vertical position. The subject responds
to a shift in the mean position of the pointer by
throwing the associated level switch in the di-
rection of the deflection. The signals are intro-
duced on randomly selected meters at randomly
varying intervals, with a mean intersignal in-
terval of 1 min.

Mental Arithmetic. In the mental arithmetic
task, the subject is required to add two numbers

and subtract a third number from the sum of
the first two. The problem elements were be-
tween 10 and 99 and were selected with the
restriction that neither digit of the third number
should be identical to the corresponding digit of
either of the first two numbers. The arithmetic
task is machine paced; a new problem is pre-
sented every 20 s. Both response time and ac-
curacy are measured on this task. Accuracy is
determined as a percentage of all problems
presented.

Pattern Identification. The display for the
pattern identification task is a -screen on the
lower left of the subject’s panel. This screen
consists of a six-by-six matrix of close-butted
lights covered by a translucent panel. A stand-
ard pattern and two comparison patterns are
presented to the subject in succession. He must
then decide if one, neither, or both of the com-
parison patterns are the same as the standard
(first) pattern and indicate his answer by press-
ing the appropriate response button. Pattern-
identification problems are presented at the rate
of 1 every 30 s. Both accuracy and response
time are kept on this task.

Group Problem Solving. The group problem-
solving task involves short-term memory and
skill at following a set procedure. Each subject
has a single pushbutton switch and three feed-
back lights mounted in the center of his panel.
In this study, the five subjects in each group
worked together to discover the correct sequence
in which to push these buttons. Each problem
sequence is presented twice in succession. In the
first presentation, the solution phase, the subjects
must determine the solution sequence by follow-
ing a standard trial-and-error search sequence.
In the second presentation, or confirmation
phase, the subjects reenter the previous solution
from memory. Response times are recorded
separately for the solution and confirmation
phases. Response time is measured from the
previous problem-solving event, either a problem
introduction or a button push. In addition, ac-
curacy in the confirmation phase is recorded as
the proportion of correct to total responses.

Two-Dimensional Compensatory Tracking. The
display for the tracking task is an oscilloscope
screen situated on top of the subject’s panel.
The target on the screen is a dot of light about
1 mm in diameter. A random movement is im-


SODIUM SUMMATION DIALS

0030
2130 0330
1830 0630 A a
. 2 3
1530 (0930 r
1230

Ww wv

A Indicates end of

control period.
per GROUP IL

Ficure 19.—Sodium summation dials for Group U1.

POTASSIUM SUMMATION DIALS

0030

0330

2130

1830 0630
2 3 \o-
aN
cA

1530
4 5
vr wv
A indicates end of
iod.
control perio: GROUP IIL

Fraure 20.—Potassium summation dials for Group ITI.

15



Tasie 2.—Results

of Sleep Survey

Group I Group II Group LIT
Sleep Total Moderate Awake or Total Moderate Awake or Total Moderate Awake or
Period Time or Deep Light Time or Deep Light Time or Deep Light
Number Asleep Sleep Sleep Asleep Sleep Sleep Asleep Sleep Sleep
(2) () (a) (hy (2) (e) CA) (a) (%)
L 80.0 69.6 30.4 80.0 72.0 28.0 96.0 61.4 38:6
2 90.4 62.6 37.4 87.8 66.8 33.2 96.0 72,0 28.0
3 84.0 69,2 30.8 89.4 82.6 17.4 97.3 70.7 29.3
4 70.8 58.0 42.0 85.4 78.4 21.6 93.3 77.3 22.7
* 53.4 48.0 52.0 - - - 55.0 27,5 72,5
5 89.2 78.6 21.4 94.6 73.2 26.8 98.7 81.3 18,7
6 73.4 60.0 40.0 96.0 73.2 26.8 98.7 89.3 10.7
7 81.4 68.0 32.0 92.0 89,2 10.8 93.3 77.3 22.7
8 84.0 74.6 25.4 97.2 73.4 26.6 97.3 72.0 28.0
9 82.6 72.0 28.0 97.2 89,2 10.8 98.7 86.7 13.3
10 90.6 80.0 20.0 91.8 90.6 9.4 93.3 78.7 21,3
iL 82.6 Th 25.6 93.2 86.6 13.4 96.0 78.7 21,3

* Short (3k-h) sleep period for Groups I and IIT.

sponse for the 11 consecutive days of the experi-
mental period.

The first group, which experienced a moderate
sleep loss on the fourth day and then returned
to the usual day/night routine, served as a con-
trol for the other two groups.

Figure 4 is a representation of HR data for
the control group. All subjects but one (Subject
2) exhibited slightly later peak-response times

SUBJECTIVE FATIGUE INDEX

20 GROUP I
z
wba BV VIN ANNA
ok pases tases taney pkad fated Paka feted ada fated tad
238883322 2 28288222222239222238e
wo PESBESSEE SF ELHSSSSESSSES LES IEE LE
6
oo GRouP I
© 2 :
w OPS AN ENN AGAALr
Obey pee eee ak etd et ek ed bet be
= ° g3ggssese 3 338333823283 823 882288
G  SFh8lserk Ff SesSESSSSSssles lasses
z

Fravre 8—Mean response of Subjective Fatigue Check-
list as a function of time of day for Groups I, II, and
III (n=5 for each group).

for HR—on the day of the sleep loss (Day 4),
on the day following the sleep loss (Day 5), or
on both days—than the peak response times
demonstrated for the first 3 days or the last 6
days.

The T,. summation dials are presented in
Figure 5 for Group I. For T;. there were no
significant changes in time of peak response for
any of the subjects throughout the 11 days, not
even on the fourth day, when the sleep loss
occurred.

Taste 3.—Daily Mean Score—Subjective
Fatigue Index

Group I Group ‘Ii Group LIT
Day 1 10.2 9.5 11.0
Day 2 8.9 9.0 97
Day 3 9.3 8.0 10.4
Day 4* weer one ----
Day 5 9.5 10.0 14
Day 6 10.2 8.2 7
Day 7 10.9 9.3 11
Day 8 10.8 Wd 10.8
Day 9 9.8 8.4 9.4
Day 10 10.3 8.0 10.6
Day 11 8.6 1.5 1.7

* Day of shift in wake-sleep cycle, fatigue indices not
executed.



Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM-76- 11

4, Title ond Subtitle ‘5. Report Date

PHYSIOLOGICAL, BIOCHEMICAL, AND MULTIPLE-TASK- November 1976

PERFORMANCE RESPONSES TO DIFFERENT ALTERATIONS OF 5 Ferloming Organivation Cole

THE WAKE-SLEEP CYCLE

=|

Performing Organization Report No.

7. Author's) E, A. Higgins, W. D. Chiles, J. M. McKenzie,
G. E,. Funkhouser, M. An Burr, A. E. Jennings, and
J, A, Vaughan
9. Performing Organization Nome and Address
FAA Civil Aeromedical Institute
P. 0. Box 25082 TT. Contract or Grant No.

Oklahoma City, Oklahoma 73125

10. Work Unit No. (TRAIS)

13. Type of Report and Period Covered

12. Sponsoring Agency Name and Address

Office of Aviation Medicine
Federal Aviation Administration OAM Report
800 Independence Avenue, S.W. 14. Sponsoring Agency Code

Washington, D.C. 20591
15. Supplementary Notes

Work was performed under Tasks AM-C~-74-PHY-73, AM-C-75-PHY-74, and AM-C-75-PHY-75.

T6. Abstract
Three groups, each comprising five healthy, mile, paid volunteers (ages 21 to
30), were studied for 11 days, Baseline data were collected for 3 days, during which
subjects adhered to a day/night routine; i.e., sleeping from 2230 to 0600. On the
fourth day each group took a "flight" in the altitude chamber. Following the flight
day, subjects in the first group (Group I) slept from only 0230 to 0600 and then
returned to the baseline routine; subjects in the next group (Group II) had their
day extended by 6 hours and began a new routine of sleeping from 0430 to 1200 for the
remainder of the study; subjects in the third group (Group III) had their day com-
pressed by 6 hours and slept from 2030 to 2400 only that fourth night and then began
a new routine of sleeping from 1630 to 2400 for the final 7 days of the study.
According to the physiological and biochemical measurements, there was little dif-
ference between the two 6-hour-change groups (Groups II and III), both of which
required longer rephasal times than did the group that experienced sleep loss but no
time change (Group I). The psychomotor performance test indicated the greatest
change in the group whose day was shortened by 6 hours (Group III). The Multiple
Task Performance Battery (MTPB) indicated the greatest deficit in performance for
Group III and the best postshift performance for Group II, Therefore, if performance
of the type represented by the MTPB is the most important consideration, then travel
from west to east (or "quick turnarounds" for shift workers) appears to be more
deleterious than changes in the opposite direction, However, this effect cannot be
predicted on the basis of the physiological and biochemical determinations made in

this study.
17. Key Words 18. Distribution Statement

Circadian rhythms, Complex performance, |Document is available to the public through
Heart rate, Rectal temperature, Urinary | the National Technical Information Service,

stress indicators, Wake-sleep cycles Springfield, Virginia 22151
19. Security Classif, (of this report) 2. Security Classif. (of this page) DI. No. of Pages | 22. Price
Unclassified Unclassified

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized



I7-KETOGENIC STEROIDS SUMMATION DIALS

0030

2130 0330
1830 0630
> 3 ,

1530 0930

1430

4 5
4 =
A Indicates end of
control period.
p GROUP I

Fieure 6.—17-ketogenic steroids summation dials for Group I.

all sleeping from 2230 to 0600 and was usually
the poorest performance score for Group I
through the remainder of the experiment. For
Group IT, the poorest performance of the day
was also the first’ performance, although after
the change its first session was at 1300. For
Group TIT the poorest performance after the
shift was either the third or fourth session of
the day, which occurred at 0800 and 1800. On
the last 2 days of the experiment, however, Group
III had its poorest performance the first session
of the day, which was at 0100.

Multiple Task Performance Battery. The
composite scores for multiple task performance
were broken down into 3-day blocks for purposes
of analysis. The blocks are the 3 days prior to
the time shift, the 3 days directly following the
time shift (Days 5-7), and the next 3 days

(Days 8-10). The final day of testing, Day 11,
was dropped from the analysis because of the
expected “end spurt” effect and because of miss-
ing data for some groups. The data for these
3-day blocks are shown graphically in Figure 22.

Each 3-day block of data was subjected to a
Lindquist Type VI analysis of variance? In
these analyses, the following sources of variance
were identified: (1) subjects, (2) groups, (3)
between subjects within groups, (4) within sub-
jects, (5) sessions (four per day), (6) periods
(two per session), (7) sessions x periods, (8)
sessions x groups, (9) periodsx groups, (10)
sessions x periods x groups, and (11) appropriate
error terms for the within-subject effects. The
probability values for each of the main and
interaction effects for each analysis are sum-
marized in Table 5. The only significant dif-


RECTAL TEMPERATURE SUMMATION DIALS
0030

0330

0630

0930

1230

A Indicates end of
control period.
GROUP I

Ficune 5,—Rectal temperature summation dials for Group I.

The urinary constituents did not present pic-
tures for the summation dials as clear-cut as
those found in the 12-h study. This difference
could be due to the sampling frequency’s being
reduced to once each 4 h (six samples per day) ;
in the 12-h study samples were collected each
3h (eight samples per day). In Group II Sub-
ject 5 was ill for part of the data collection
period and gave questionable results for some of
the parameters; also, in Group III, Subject 4
was found to have glucose in his urine, which
interfered with some of the biochemical assays,
particularly the 17-KGS determinations,

The summation dials for the urinary con-
stituents are found in the following figures: For
Group IT, Figures 11, 12, 13, 14, and 15 give the
summation dials for epinephrine (E), nonrepine-
phrine (NE), 17-KGS, Na‘, and K°* respectively ;

for Group III, Figures 16, 17, 18, 19, and 20
present the summation dials for E, NE, 17-KGS,
Na’, and K* respectively.

Psychomotor Performance. Although each in-
dividual was given 60 trial sessions on the Kugel
apparatus during the training period that pre-
ceded the experimental phase of these studies,
the learning effect was still apparent to the end
of the experiment. Even though the mean daily
scores showed little or no improvement from
Day 7 to 9 for all three groups, scores again
increased on Days 10 and 11. The results of the
psychomotor performance task are presented in
Figure 21 and Table 4. Patterns for peak per-
formance at a given time of day were not readily
apparent. However, in general, the first per-
formance of the day was the poorest for all
groups on the first 8 days when the subjects were



SLEEP SURVEY RESULTS

GROUP I GROUP IL GROUP I

600 LTT 2400 LEI
= 1200 ZL N I
0600 wi" 24 00 LIZZ
a my 1200 ZA\0
a 0600) 2400 LLZLZZZZZZZZZZANO
wi 1200 Zag
w 0600 AS 2400 LALLA 9
® seo0 je «1200 Za8
rr 2400 WLLL
ro} | 200 LLL
i 2400 WLLL
2 og00 me 1200 Za6
Ww 2400 LLL
ke 1200 LALZZZZZZZZZZZZZEL
<< 0600LZZZZA * 6 2400 WIZ, **5
2 060022 + 0600 Za% 600) ZA
2
2 0600 Zs 0600 ZA3 0600 Bs
x
S 0600 ZA +0600 ZA2 0600 Ze
@ 0600) ZA\ 0600 ZA' 0600 ZA\

0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100

PERCENT SLEEP DURING SLEEP PERIODS

2K SLEEP PERIOD. 0230-0600 ONLY

2K SLEEP PERIOD 2030-2400 ONLY

Figure 2,—Mean scores from Sleep Survey for Groups I, II, and III (n=5 for each group).

TI slept 95.6 percent of the time available for
sleep. After the change in their routine, Group
II increased their percentage of sleep signifi-
cantly, averaging 94.2 percent of the sleep time
the first 3 days after the change and 94.1 percent.
for the last 3 days of the experiment. Group
III, which reported the greatest sleep percent-
age, demonstrated little change in their time
asleep, sleeping 96.9 percent of the sleep periods
the first 3 days after the change and 96.0 percent
for the last 3 days of the experiment. Group I
demonstrated no change for the first 3 days after
the “flight” day (81.3 percent) and a small in-
crease (85.3 percent) for the final 3 days. Groups
I and III demonstrated rather low percentages
of sleep (53.4 and 55.0 percent respectively)
during their short (814-h) sleep segments on the
day of the change. ‘

A graph of results of the Subjective Fatigue
Indices is presented in Figure 3. The daily

averages for each group are listed in Table 3.
The daily averages for the control group (Group
I) demonstrate the least variability, ranging
from 8.6 to 10.9 (lower scores indicate greater
rated fatigue). Their greatest fatigue was indi-
cated for the last day of the experiment. Group
II indicated their greatest feclings of fatigue
during the middle of the postshift period. Group
III indicated their greatest fatigue the first day
after the change in the wake-sleep cycle.

Physiological and Biochemical Responses. The
physiological and biochemical data were collected
at regular time intervals throughout the experi-
mental period. This schedule allowed treatment
of the data by Fourier analysis and determina-
tion of the 24-h time of peak response. The
24-h peak-response data were subsequently pre-
pared in summition-dial format,’ which is a
vectorial representation of the time of peak re-


Taste 5.—Summary Table of p Values from
Analyses of Variance

Pre Post 1-3 Post 4-6

Groups 201

Sessions 201 01 201

Periods 01 205

Sessions x Periods — 01 201

Sessions x Groups 01 01 .01

Periods x Groups -01

Sessions x Periods x Groups o 01 201

course of the experiment whereas, with the ex-
ception of the final session of the day, the per-
formance of Group II was maintained essentially
at the preshift levels for the postshift blocks of
the study.

IV.

Subjective Forms. The results of the sleep
survey seem to indicate good adjustment on the
part of the subjects to the laboratory setting.
Group I consistently reported a lower percentage
of sleep during the sleep periods. However, the
lower mean was due primarily to one individual
(Subject 2) of this group. He reported sleeping
only about 48 percent of the sleep periods during
the control days, about 45 percent during the
first 4 days after the “flight” day, and 80 per-
cent during each of the last 3 days of the experi-
ment. On the other hand, he did not report any
subjective feeling of fatigue greater than that of
any other member of the group, nor were any of
his physiological or biochemical measurements
out of line.

Group I subjects demonstrated the least im-
pact on their daily mean score of the Subjective
Fatigue Index because of the experimental pro-
tocol. Group TIT showed the greatest fatigue on
Day 5 immediately after the change in their
wake-sleep cycle; however, these subjects ap-
peared to recuperate quickly and return to con-
trol levels. Group II subjects, on the other hand,
appeared to suffer greater fatigue in the middle
of the postshift period. The psychomotor per-
formance scores appear to verify some of the
fatigue results; ie. Group II’s performance
actually improved 4.8 percent from Day 38 to
Day 5, while Group III declined in performance
4.7 percent from Day 3 to Day 5.

Discussion.

18

Physiological and Btochemical Responses.
With the exception of HR data, which demon-
strated rather rapid adjustments for all groups,
the rephasal times for Groups IT and III appear
to be shorter than that required for the 12-h-shift
group. Rectal temperature measurements ap-
peared to demonstrate a rephasal time only one-
half as long for the two 6-h-shift groups as for
the 12-h-shift group. It is difficult to make
determinations for the urinary constituents
measured because of the fewer samples collected
per subject and the small number of subjects in
each group. However, it appears evident that
the 17-KGS again required the longest rephasal
time of those parameters measured.

It was anticipated that Group IIT, for which
the day was compressed by 6 h, would require
an adjustment period greater than that of Group
II, for which the day was lengthened by 6 h.
In other studies®’*"? involving actual time zone
displacements, the groups traveling from west
to east demonstrated longer adjustment periods
than those traveling from east to west. This
was not the case for our T,. measurements, nor
was it discernible from the other physiological
and biochemical measurements. There were evi-
dences of this reported trend in the fatigue
indices, the psychomotor performance task, and
the MTPB results. Perhaps, the adjustment of
physiological parameters was facilitated by
Group ITI’s 314-h sleep period on the day of the
shift change. This permitted a 6-h shortening
of the day rather than an 18-h lengthening of
the day as might have been experienced without
the sleep period. It has been suggested that the
longer rephasal times required for west-to-east
travel could well be a function of the scheduled
flight times. Evening flights from the east coast
of the United States arrive in Europe in the late
morning hours of the following day. If one
assumes little effective sleep aboard these flights,
passengers miss one entire sleep period. This is,
of course, always true for the flight crews. One
study? suggests that for humans, lengthening of
the day is a more normal response than shorten-
ing of the day, because results of free-running
experiments (ones in which all time cues are re-
moved) show more individuals tend to develop
rhythms greater than 24 h. The same study?
also suggests that sleep obtained in late afternoon
and early evening hours, when activity levels are
normally at their highest, is less effective than




EPINEPHRINE SUMMATION DIALS
0030
2130 0330

1830 one
\ 2 3
1530 (0930 ‘

AR SY.

A Indicates end of

trol period.
GROUP II contro! Per"

Figure 11.—Epinephrine summation dials for Group II.

NOREPINEPHRINE SUMMATION DIALS

0030
2130 0330
1830 0630
2 3
x ‘
1530 0930
1230

es SS

A Indicates end of
control period.
GROUP IL

Ficure 12.—Norepinephrine summation dials for Group II.

ll



POTASSIUM SUMMATION DIALS

0030
2130 0330
1830 0630
2 “ 3
1530 1930 \
1230
4 s 5

A Indicates end of
control period.
GROUP ID

Ficurn 15.—Potassium summation dials for Group II.

EPINEPHRINE SUMMATION DIALS
0030

0330

1830 0630
2 3
1530 4 Y
1250
4 5
vr v

A Indicates end of

it iod.
control perio GROUP II

Ficurn 16.—Epinephrine summation dials for Group ITT.

13



ACKNOWLEDGMENT

The authors gratefully acknowledge the contributions of Ms. Patsy
Fowler, and Mr. Russell Moses of the Aviation Physiology Laboratory’s
Stress Analysis Research Unit for their biochemical analyses of the urine.
They also wish to thank Ms. Georgetta West and Mr. Steve Burke of the
Aviation Psychology Laboratory’s Human Performance Research Unit for
their administration of the CAMI Multiple Task Performance Battery.





HEART RATE SUMMATION DIALS

0030

0330

1230

| Indicates end of
control period.
GROUP IL

Fioure 7.—Heart rate summation dials for Group Il.

HEART RATE SUMMATION DIALS

0030

2130 0330

1830 0630
- 2 - 3

1530 10930

1330
4 5
- 7

I Indicates end of
control period. GROUP I

Figure 8—Heart rate summation dials for Group IIT.

9



I7-KETOGENIC STEROIDS SUMMATION DIALS
00:

30
2130 0330
1830 0630
2 a? 3
~
1530 1930
1230

4 5
AY
‘
A Indicates end of

GROUP I control period.

Fieure 13.—17-ketogenic steroids summation dials for Group II.

SODIUM SUMMATION DIALS
0030

2130, 0330

1830 0630
2 3
1530 0930
L

\ os
4 5

A Indicates end of

GROUP I control period.

Fievure 14.—Sodium summation dials for Group IT.

12