RE

ny
r
oI

ERENCES

Jennings, A. E., W. D. Chiles, and G. West: Methodology in
the Measurement of Complex Human Performance: Two-Dimensional
Compensatory Tracking, FAA Office of Aviation Medicine Report
No. AM-72-21, 1972.

Melton, C. E., J. M. McKenzie, B. D. Polis, S. M. Hoffmann,
and J, Tf, Saldivar, Jr.: Physiological Responses in Air
Traffic Control Personnel: Houston Intercontinental Towes,
FAA Office of Aviation Medicine Report No. AM-73-21, 1973.

16


REFERENCES

Gray, S. J., J. A. Benson, H. M. Spiro, and R. W. Reifenstein:
Effects of ACTH and Cortisone Upon Stomach, GASTROENTEROLOGY,
19:658-673, 1952.

Kirsner, J. B., A. P. Klotz, and W. L. Palmer: Unfavorable
Course of Gastric Ulcer During Administration of ACTH and
Cortisone, GASTROENTEROLOGY, 20:27-29, 1952.

Maling, H. M., and Benjamin Highman: Exaggerated Ventricular
Arrhythmias and Myocardial Fatty Changes After Large Doses of
Norepinephrine and Epinephrine in the Unanesthetized Dog,

AM. J. PHYSIOL., 194:590-596, 1958.

Melton, C. E., J. M. McKenzie, B. 9D, Polis, G. E. Funkhouser,
and P, F, Iampietro: Physiological Responses in Air Traffic
Control Personnel: O'Hare Tower, FAA Office of Aviation
Medicine Report No. AM-71-2, 1971.

Melton, C. E., J. M. McKenzie, R. C. Smith, B. D. Polis,

E., A. Higgins, S, N, Hoffmann, G. E, Funkhouser, and J. T.
Saldivar, Jr.: Physiological, Biochemical, and Psychological
Responses in Air Traffic Control Personnel: Comparison of
the 5-Day and 2-2-1 Shift Rotation Patterns, FAA Office of
Aviation Medicine Report No. AM-73=22, 1973,

Melton, C. E., J. M. McKenzie, J. T. Saldivar, Jr., and S. M.
Hoffmann: Comparison of Opa Locka Tower With Other ATC
Facilities by Means of a Biochemical Stress Index, FAA Office
of Aviation Medicine Report No. AM-74-11, 1974.

Melton, C. E., R. C. Smith, J. M. McKenzie, J. T. saldivar, Jr.,
S. M. Hoffmann, and P. R. Fowler: Stress in Air Traffic
Controllers: Comparison of Two Air Route Traffic Control
Centers on Different Shift Kotation Patterns, FAA Office of
Aviation Medicine Report No. AM-75-7, 1975,

Melton, C. £., R. C, Smith, J. M, McKenzie, S. M. Hoffmann, and
J. T. Saldivar, Jr.: Stress in Air Traffic Controllers:

Effects of ARTS-III, AEROSP. MED., 47(9):925-930, 1976.

Smith, R. C.: The State-Trait Anxiety Inventory and the
Assessment of Stress in Private Pilot Training. Proceedings

2°8


7

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(Figure 1). Electrodes were attached to the subjects for

heart rate recordings, and subjects were given a thermistor
rectal probe for self-insertion for rectal temperature measure-
ments. The subjects then reported to the altitude chamber

for a 3-h test session. Heart rate was recorded continuously,
rectal temperature and blood pressure were measured once during
each 15-min period, and tests of visual accommodation (provided
by Dr. K. W. Welsh of che Aviation Physiology Laboratory) were
administered before the session and at the end of each hour.
Capiliary blood samples from finger punctures were drawn before
and after each test session for determinations of blood glucose
and hematocrit. At the end of the 3-h test, subjects filled
out a symptom checklist (Figure 2) and again executed a sub-
jective rating scale (Figure 3). At the end of the 3-h test,
urine was collected for measurements of epinephrine, norepineph-
rine, and 17-ketogenic steroids (2). After each chamber
session, subjects were given a cardiovascular evaluation.

During each 3-h test session, the subjects performed four
different combinations of tasks of the MIPB in 1-h cycles,
(For a complete description of the tasks, see Jennings, Chiles
and West(1).) Lights and meters monitoring tasks were per-
formed throughout the test session. During the first 15 min
of the hour, tracking arithmetic tasks were performed. During
the second i5 min, arithmetic and problem solving were per-
formed. During the third 15 min, pattern discrimination and
problem were performed. And, during the final 15 min, pattern
discrimination and tracking were performed. This sequence was
then repeated during the second and third hours of the test
session. The measure of performance used was an equal-variance
composite of the various time and accuracy measures from the
individual casks.

Twelve subjects were selected and 10 completed the test
series. Data collection was accomplished in three periods:
March 15 to April 16, June 1 to Jume 24, and June 28 to
August 2, 1976.

The sleep surveys indicated no difference in the quality
or quantity of the subjects’ sleep prior to the test days.

According to the results of the subjective rating scales,
attentiveness decreased significantly from the beginning co


TABLE 4. Pathology and Individual Stress
Indices for Various ATC Facilities

ATC Disease
Facili a ye ~
acility Category Cot ial ce Pp fue p*
O'Hare Tower
Normal 1.23 0.74 0.99
Gastrointestinal 1.73 nst* 0.71 ns 0.79 ns
Cardiovascular 2.91 7 1.07 + 1.51 +

Neuropsychiatric 1.56 ns 0.71 ns 0.73 os

Opa Locka Tower

Normal 0.67 0.74 1.21
Gastrointestinal 0.00 = 9.00 + 0.00 +
Cardiovascular 0.00 7 0.00 + 0.00 +
Neuropsychiatric O.17 = 0.63 =F 0.42 +
Miami ARTCC
Normal 0.59 0.68 8.88
Gastrointestinal ©.73 ns 0.42 ns 0.78 ns
Cardiovascular 0.74 xs 0.693 ns 1.43 0.UD
Neuropsychiatric 0.65 ns 0.84 ns 0.96 ns
Atlanta ARTCC
Normal 0.80 6.29 1.38
Gastrointestinal 0.00 7 0.00 7 0.00 7
Cardiovascular 34 7 0.53 + 1.25 7
Neuropsychiatric 0.59 ns 0.52 nas 1.31 ns
Fort Worth ARTCC
Normal 0.23 0.54 0.20
Gastrointestinal 0.09 = 0.88 F 0.36 46+
Cardiovascular 0.60 = 1.04 7 0.16 7
Neuropsychiatric 0.24 «is 1.21 ns 0.20 ns


Tr

bei

ASSESSMENT OF CARDIOVASCULAR FUNCTION AFTER EXPOSURE
TO THE AVIATION STRESS PROTOCOL~-SIMULATION

Introduction.

The Aviation Stress Protocol--Simulation (ASPS) was
designed to assess the potential for impaired performance by
testing the capacity of pilots and air traffic controllers
to: (i) maintain an optimum performance level for a prolonged
period of time and (ii) respond to a tass overload or emer-
gercy situation. For pilots, this capability includes the
ass.ssment of tolerance to flight environmental stresses in
the range of altitudes to which general aviation pilots can
legally fly without supplemental oxygen. The core of the
ASPS for pilots) is the exposure of the individual for
single-day 3-h periods to a battery of simulated complex
psychomotor tests (MTPB) at ground level (GL) and chamber
altitudes at 8,000 (A), 10,500 (3B), and 12,500 (C) feet (MSL).
During the ASPS, task performance is monitored for deteriora-
tion of psychomotor performance and physiological and bio-
chemical tests are administered to identify possible causes
of such deterioration,

As an adjunct procedure, cardiovascular tests were admin-
istered immediately following the ASPS to identify any func-
tional deterioration due to the ASPS exposure per se his
report will deal oniy with the post-ASPS cardiovascular
testing.

The cardiovascular test battery consisted of: (i) a test
of orthostatic tolerance using a lower body negative-pressure
(LBNP) box (supine) and (ii) a submaximum physical workload
test using standardized, upright, seated, bicycle ergometry.
The LBNP load and time sequences were a 3-min rest period, a
2-min exposure to -25 wm Hg LBNP (= +1.5 Gz), a 2-min
recovery/rest period, and a 2~min exposure to -50 ma Hg LBNP
(= +2.0 Gz}. The ergometry load and time sequences were a
S-min rest period, a 3-min exposure to a 50 rpm/30 & workload,
and a 3-min exposure to a 50) rpm/60 W workload. Parameters
assessed during the LBNP test were pulmonary ventilation
(using direct spirometry), heart rate (HR) and electrocardio-
gram (singlie-lead ECG), blood pressure (automatic sphygmoma-
nometry), and temporal artery flow velocity (directional

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TABLE 4 (Continued)

Facility Category Cor ORF OSS Be co p*

Houston

Intercontinental

Tower
Normal 1.01 0.40 0.59
Gastrointestinal 1.77 + 0.96 + 0.57 +
Cardiovascular 1.77 + 0.96 + 0,57 +
Neuropsychiatric 0.00 + 0.00 + 0.00 tT

Oakland TRACON
Normal 0.37 0.85 0.48
Gastrointestinal 0.48 + 0.41 + 0.30 +
Cardiovascular 0.00 + 0.00 + 0.00 +
Neuropsychiatric 0.00 + 0.00 + 0.00 7

Los Angeles

TRACON
Normal 0.63 0.38 0.79
Gastrointestinal 0.00 + ©€.00 + 0.00 +
Cardiovascular 0.00 + 9.00 + 0.00 +
Neuropsychiatric 0.00 + 0.00 + 0.00 +

rs
!

diseased

Not significant

2’

= Level of significance of difference between normals and

Namher of cases insufficient for statistical treatment


oO

onclusion.

In future experiments using the ASPS, the cardiovascular
testing will be conducted separately. The time of exposure
to altitude and MTPB testing will be limited to 2h. Measure-
ments such as visual accommodation, internal body temperature,
blood glucose, blood drug or aicohol level, and others will
be included in the ASPS experiments only when appropriate.


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TABLE 3.

Normal
Gastrointestinal
Cardiovascular

Neuropsychiatric

*p = Level of significance of difference between normal and

Pathology and Grouped Stress Indices

for the Entire Subject Population

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1.12
0.94

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Il.

THE RELATIONSHIP BETWEEN STRESS-RELATED METABOLITES AND
DISQUALIFYING PATHOLOGY IN AIR TRAFFIC CONTROL PERSONNEL

Introduction.

This laboratory's first study of stress in air traffic
controllers was carried out in 1968 at O'Hare Tower. Since
that time, 15 other studies have been carried out at towers,
centers, TRACON's, and flight service stations (4-10). A
total of 237 controllers representing trainees, journeymen,
and supervisors have been studied; 189 of those are the sub-
jects of this study--48 were either studied tor recently for
their data to be available or their urinary data were incomplete.

Sufficient time has elapsed since the first study at O'Hare
that some controller subjects have suffered a variety of medi-
cal conditions severe enough to require either waiver or retire-
ment. Notations regarding medical conditions requiring either
of the above actions are in the controllers’ files in the
Aeromedical Certification Branch of the Civil Aeromedical

Institute. These files were searched for controller subjects

who developed medical conditions after they were studied.
Thirty-six (19 percent of the total) such controllers were iden-
tified who developed pathology after the time of the stress

study in which they served as subjects, These controllers showed
pathology in one or more of three groups: gastrointestinal,
neuropsychiatric, and cardiovascular (Table 1). A further break-
down of the three conditions by region and facility is shown in
Table 2.

Results.

An index developed in this laboratory (6) readily allows
the comparison of excretion values for 17-ketogenic steroids,
epinephrine, and norepinephrine. The average of the three indi-
vidual indices (oes cus and che? is the composite stress index

(co). The individual and composite indices for normal controllers

(those without a pathology file) and those with pathological con-
ditions are shown in Table 3. The table shows that for the whole
population of controllers, those who developed gastrointestinal

pathology had significantly (p< 0.01) higher Coe than did their

normal counterparts at the time they were studied. The index

a!


SY¥LPTOMS DEGREL* WHEN OCCURRED
mild moc, severe he.-l hr.-2hr.-3

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Di

cult Coordination
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[ aS SD Se
a

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Hearing Symptoms

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¥ Mild - not of sufficient degree to impair performance

Moderate - cf sufiicient degree to possibly impair performance

Severe - of sufficient degree to definitely impair performance

Observer's Comments:



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1. Jennings, A. E., D. Chiles, and G. West: Methodology in
the Measurement of Complex Human Performance: Two-Dimensional
Compensatory Tracking, FAA Office of Aviation Medicine Report
No. AM-72-21, 1972.

2. Melton, C. E., J. M. McKenzie, B. D. Polis, S. M. Hoffmann,

and J. 1. Saldivar, Jr.: Physiological Responses in Air

Traffic Control Personnel: Houston Intercontinental Towec,
FAA Office of Aviation Medicine Report No. AM-73-21, 1973.

1€


iv.

the end of the 3-h experiment at both 8,000 ft and 12,500 ft
(Figure 4); a corresponding decrease in energy level was
reported (Figure 5). Interest decreased with time of exposure
at all altitudes, with statistical significance at the 0.05
level for ground level and 8,000 ft and at the 0.01 level for
10,500 and 12,500 ft (Figure 6).

Concentration difficulty and drowsiness were the most fre-

quently reported symptoms on the checklist; more subjects reported

these two symptoms tor 12,500 ft than for the other altitudes.

The visual accommodation tests yielded no statistically
significant findings attributable to either altitude or duration
of the test.

Hematocrit demonstrated a slight but statistically insig-
nificant hemoconcentration through time at each of the four
altitudes, The blood glucose was significantly less at the
end of the experiments than at the beginning, but there were
no differences attributable to altitude (Figure 7).

There was a statistically significant increase in heart rate
with increasing altitude (Figure 8). There were no statisti-
cally significant differences for systolic blood pressure, but
diastolic pressure did demonstrate a statistically significant
decrease (p < +05) at 12,500 ft (Figure 9).

The findings of the urine analyses are presented in Table 1.

Although the catecholamines, epinephrine, and norepinephrine
demonstrated increasing values with each increase in altitude,
the individual variances were large and the differences did
not prove to be statistically significant,

The performance data from the MTPB exhibited great varia-
bility with no effects that could be attributed to altitude.
In addition, the performance levels, when averaged over alti-
tude conditions, showed a significant drop as a function of
the number of test sessions experienced, Apparently, the sub-
jects were losing interest in, or losing motivation to comply
with the demands of the experiment.

Discussion.

The series of experiments conducted during the development
of the ASPS provided information indicating a need for

6


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8


TABLE 2. Distribution of the Three Major Disease
Categories Among Regions and Facilities

Gastro- Cardio- Neuro-
Region Facility intestinal vascular psychiatric
Southern
Opa Locka Tower 0 9 1
Miami ARTCC 3 8 12
Atlanta ARTCC o i 3
3 9 16
Southwest
Houston Inter-
continental Tower t 1 0
Fort Worth ARTCC i L 3
2 2 3
Central
O'Hare Tower (1968) 4 l 2
vestern
Los Angeles TRACON a) 0 0
Oakland TRACON Ll oO _0
1 ie) 0


TABLE 1. Distribution of Diagnoses Among
Three Major Disease Categories

iS)

Anxiety Neuroses
Psychosomatic Illness

Disease Percentage
Category Diagnosis Occurrence
Gastrointestinal
Gastric Ulcer 15.4
Duodenal Ulcer 15.4
Peptic Ulcer 15.4
Gastritis 15.4
Gall Bladder 7.7
Other 30.7
Cardiovascular
Myocardial Infarction 26.7
Coronary Insufficiency 6.7
Hypertension 33.3
Angina 13.3
Arteriosclerotic Heart Disease 13.3
Arrhythmia 6.7
Neuropsychiatric
Anxiety Reaction 21.8
Anxiety Depression 21.8
"Neuroses" 8.7
Cluster Headaches 4.3
Depression 4.3
Personality Disorder 4.3
Schizophrenia 8.7
1.8
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Doppler equipment). During ergometry testing, the same
parameters were assessed excepting the omission of the tem-
poral artery flow velocity and the addition of oxygen uptake
(analysis of quantitatively collected expired air).

immediately following a given ASPS altitude exposure, the
subject (seated in a wheelchair at all times) was "finger
pricked" for microsampling of blood, wheeled to a private
room for quantitative collection of urine, and then delivered
to the cardiovascular testing room, The average elapsed time
between the end of altitude exposure and start of the LBXP
and ergometry tests were 44 and 63 min respectively.

A complete set of ASPS altitude exposures was achieved
on a total of 10 normal male subjects (21-25 yr of age).
The GL data served as baselines for comparing displacements
due to altitudes A, B, and C.

Results.

LBNP. Both levels of +Gz exposure were well tolerated
by all subjects without syncope or temporal artery flow
reversal, Although syncope was absent, physiological displace-
ments did occur in all subjects. In general, the displace-
ments increased in rough proportion to the applied level of
+Gz and the preceding altitude exposure. The quantitative
aititude-related displacements of the systolic blood pressure
(SBP), diastolic blood pressure (DBP), pulse pressure (PP),
HR, temporal artery flow velocity (TAFV), and pulmonary ven-
tilation (¥_) are summarized in Tables 1-3. The SBP dropped

during each +Gz exposure, but the drops and overall leve's
appeared to be approximately the same for GL as for preceding
altitudes A, 5, and C as compared to GL. The PP generally
dropped during each +Gz exposure, and the overall levels were
also lower following altitudes A, B, and C as compared to GL.
The HR increased during each +Gz exposure, and the overall
levels were also higher following altitudes A, B, and C as
compared to GL. In each of the two +Gz exposures and the two
preceding rest periods, most of the altitude-related increases
in ER (A, 5, and C compared to GL) were statistically signifi-
cant (p< 0.95). In the altitude context of comparison, four

of the DBP and two of the PP displacements were also significant.

The TAFV dropped during each +Gz exposure, but the overall
levels were substantially higher following altitudes A, B, and



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DEVELOPMENT OF THE AVIATION STRESS PROTOCOL--SIMULATION
AND PERFORMANCE, PHYSIOLOGICAL, AND
BIOCHEMICAL MONITORING SYSTEMS: PHASE I

Introduction.

The Federal Air Surgeon, in his FY-75 Call for Estimates,
said, "I have determined that the highest priority will be
research in support of medical certification and medical stand-
ards development." in response to this priority statement,
the Aviation Physiclogy Laboratory began to design a broad
research program to provide clinical aviation medicine with
information needed for medical certification decisions and
for developing and revising medical standards.

The Aviation Stress Protocol--Simulation (ASPS) focuses
on the fact that any assessment of fitness in pilots and air
traffic controllers must take into account their potential for
impaired performance. Not only must they perform their routine
tasks at optimal levels for prolonged periods of time, but
these persons must also retain the capacity to respond to
task overloads in emergency situations, For pilots, there
must be a normal tolerance to flight environmental stressors,
particularly to the range of altitudes where general aviation
pilots can fly without their requiring supplemental oxygen.

Because performance was an important consideration, per-
formance measurements were made using the Civil Aeromedical
Institute (CAMI) Multiple Task Performance Battery (MTPB) (1).

Experiment Design.

Healthy, male, paid volunteers (aged 21 to 28 years)
served as test subjects, interviews and physical examinations
were conducted for all prospective subjects pricr to selection.
After selection, subjects were trained on the MIPB equipment
and the vision testing equipment. Subjects were then tested
individually in the CAMI research altitude chamber at each
of four simulated altitudes. These (MSL) altitudes to which
the subjeccs were exposed in random sequence were ground level,
8,000 ft, 10,500 ft, and 12,560 ft. Subjects reported to the
laboratory without eating breakfast and were given a standard
meal before beginning the experiment. After breakfast, sub-
jects completed a sleep survey and a subjective rating scale



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refinement of the protocol. Results of some of the subjective
rating scales showed that increasing altitude accentuated
changes that occurred primarily as a result of the long experi-
mental procedure; i.e., interest decreased more at the two
higher altitudes. Further, concentration difficulty and drow-
siness were reported most frequently at 12,500 ft.

In mid-August 1976, conferences were held vy Drs, Busby,
Melton, Collins, Chiles, Lategola, and Higgins to evaluate
the findings to that time. The general conclusions were:

A. The experiments were too long and too complicated.

8, The experiment protocel itself probably had greater
effect on the subjects’ responses than did the differences
in altitude.

C. The data obtained from the MTPB and cardiovascular
testing were not conclusive.

D. Further refinement of the protocol is indicated. In
future experiments, the cardiovascular tesving should be con-
ducted separately, in parallel with other testing, and not
at the end of an already long test procedure.

E. The time spent in the altitude chamber for a test
2

session should be reduced to 2 h to preclude the boredom and
fatigue associated with the longer testing procedure,

F. Additional tests should be conducted to determine the
sensitivity of the MTPB for detecting differences due to
altitude alone.

Between August 28 and November 18, 1976, shorter tests
(2 h) were conducted at three altitudes; ground level, 12,506
ft, and 14,000 ft. Ten subjects were evaluated. The cardio-
vascular testing, visual accormodation tests, dietary control,
and blood sampling were eliminated from the pretocol. This
seriés of tests was conducted primarily to evaluate the effects
cf altitude on complex performance. Unfortunately, subject
motivation again appeared to fluctuate widely and again,
altitude did not have a significant effect on performance.
In the past, the problem was produced by rather frequent MTPB
equipment malfunctions.

14


Technical Keport Documentation Page

TS, Recipsert's Covalog No. |

i

i | i
i}
|

T. Report No. } a. Govevsmen’ Accessran Nov

FAA-AN- 95-5

4. Title and Subtitle — 3. Report Date i

Performing Organizeton Code

if
|
|
if
|
1
i
| THREE REPORTS RELEVANT TQ STRESS IN AVIATION PERSONNEL

L 8. Performing Organization Report No.
| 7. Author's)
| = =

- A. ligg

Pertorming Organization Nome ana Address

us, MH. T. Lategola, and C. E. Meltoa

sol tm

Wor Unit No. sTRAIS) i
AA Civil Aeromedical Instituse
- O, Box 25082

Oklahoma City

> Contract o Grant No.

Oklahoma 73135

Qi

13. Type of Resort and Perios Covered

of Aviation Medicine
+ Aviation Adminiscracion
Independence Avenue, ©.N. #4” Sponsormng Agency Code

Washington, D.C. 20591
15. Supplementary Notes

as performed under approved Tasks AN-C-76-PHY-82, AM-A~76-PHY-79, and

on CASPS), the fol-
S$, cardiovascular

viation stress prorocoi-=si
tow! ng conclusions were reached: (1) In experiments using th
testing will be conducted parailel, but separately; (2) The time of exposure to

Palti will be limiced ro 2 hy; and (3) ts such as visual accommodation,
inter ly temperature, biood glucose, blood drug or alcohol level, and others

n the ASPS only when appropriat:

fh

leasure!

:

i

H

t

|

i

| Cardiovascular and pulmonary parameters were assessed under simulated +Gz and exer~

| cise conditions in normal males after exposure to the ASPS. Some parameters were

| displaced to a statistically significant degree, but such h displacenents are of doubt-
| ful paysiologicai significance because of the unavoidable tine lapse between altitude
} exposure and sssessment. These preliminary experiments served to demonstrate tha

| meaningfu? physiologicei assessments car

j the ASPS.

|

1

|

only be made during exposure to the alzi-

i controller subjects from previous stress studies were identified who sub-

q uffered medical conditions severe enough to require waiver or retirement.

e jeors! stress indices were compared with those of subjects who bad no known
pathclogy to see if any o: the stress indicators were predictive of pathological

conditions. The data showed that controllers who developed gastrointestinal pathol-
ogy had significantiy (p< 0.01) higher oo, than did thzir normal counterparts. At

iami ARTCC,

y elevated (p< 0.05) in the cardiovascular group.

18. Distribunon Statement 1

M

17. Key Words

i
wlation, Aeromedical “Certification, |
eromedical Standards, Cardiovascular jocument is available to the public through
tion, Physiological Monitoring, he National Technical Information Servize,

|
}
|
i
i
io
i
\
q

io: Monitoring, Stress, and Air Springfield, Virginia 22161 i
(traffic Controller. L |
| 19. Security Clossif. {of this report} 20. Security Classif, (of thus paged [2h No. of Pages | 22. Price 7
H _ oes i
fnelassi tied Unclassified a 34
Form DOT F 1700.7 (8-72) Reproduction of completed page authorized


10.

ll.

of the 80th Annual Convention of the American Psychological
Association, 7:64-65, 1972.

Smith, R. C., and C. E. Melton: Susceptibility to Anxiety
and Shift Difficulty as Determinants o£ State Anxiety in Air
Traffic Controllers, AEROSP. MED., 45:599-601, 1974.

Thorn, G. W., D. Jenkins, J. C. Laidlaw, F. C. Goetz, J. F.
Dingman, W. L. Arons, D. H. P. Streeten, and B. H. McCracken:
Pharmacologic Aspects of Adrenocortical Steroids and ACTH in
Man, N. ENGL. J. MED., 248:323-337, 1953.


C compared tc GL. None of the observed blood flow velocity
displacements was statistically significant. The v. response

to each +Gz exposure varied widely in direction and magnitude
with no obvious consistent relationship to either +Gz or
altitude,

Ergometry. Both the 30- and 60-W workloads were com~
fortably tolerated by all subjects. The SBY, DBP, PP, HR,
ve and oxygen uptake We > increased generally in direct

2
proportion tc the applied ergometric load. With the exception
of PP, the overall levels of these parameters were higher
following altitudes A, B, and C as compared to GL. The overall
levels of PP were lower following altitudes A, B, and C as com-
pared to GL. The quantitative altitude-related displacements
of the SBP, DBP, PP, HR, veo and % are summarized in Tables
2
4-6, Statistically significant (P< 0.05) altitude-related
changes occurred: (i) in DBP, PP, HR, and % in the
2

preergometric rest period; (ii) in DBP, PP, and HR during the
30-W workload; and (iii) in HR and V_ during the 60-W workload.

Discussion.

Some st’ istically significant altitude-related displace-
ments in physiological parameters appeared in beth the LBNP
and ergometry segments of the post-ASPS cardiovascular assess-
ment, even though these two testing segments nonoptionally
followed the end of altitude exposure by an average of 44 and
63 min respectively. Because these displacements could
possibly be accentuated by closer temporal proximity of the
cardiovascular testing to the altitude exposures, it was
decided that the cardiovascular testing would henceforth be
run in parallel rather than in tandem with the core ASPS.
the cardiovascular tests are to be applied at Gl and during
appropriate altitude exposures rather than after the altitude
exposures. During the currently extended "shakedown" Phase I
testing of the core ASPS, the paralleling cardiovascular
equipment and protocol will be shifted to one of the small
altitude chambers. We should be ready to resume full-scale
peraliel testing when the core ASPS commences its Phase II
operations. Running this test in parallel with the core ASPS
tests further has the beneficial effect of relieving the tedium
of the core tests by reducing the lergth of subject exposure.

{-6


TFC


for norepinephrine Cc) was also elevated significantly

(p < 0.05) over the normals for the cardiovascular pathology
group.

When the individual facilities are considered, c e is
n

significantly (p < 0.05) elevated in the cardiovascular pathol-
ogy group at Miami ARTCC (Table 4). There are no vther points
of significant difference.

Discussion.

This study indicates that high levels of steroid excretion
are related to the presence or later development of gastro-
intestinal disease, the most common "stress related" disease.
As shown in Table 1, the principal subcategories of that
disease relate to ulceration of the stomach and duodenum.
Ulcers have long been known to be related to high levels of
endogenous steroids (1,2,11).

At Miami Center, the occurrence of cardiovascular disease
(25 percent hypertension, 75 percent coronary artery disease)
is significantly related to high levels of norepinephrine
excretion. Norepinephrine is the principal catecholamine
liberated by the sympathetic nervous system and is, therefore,
the main regulator’ of arteriolar resistance, Norepinephrine
has also been shown to have pronounced effects in causing
arrhythmias and fatty changes in the hearts of dogs (3).

This study suggests that excretion levels of 1?-ketogenic
steroids and norepinephrine may be predictive of heart disease,
hypertension, and gastrointestinal ulceration. However, because
of the smali number of controllers in each diagnostic category,
the statistics leave much to be desired; the findings reported
here are, therefore, tentative, and this report should be
viewed as preliminary. The pathology files will be periodi-
cally checked in the years to come to see if the statistical
valicity of these observations changes as more controllers
join the list of those with pathology files.

75


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FIGURE 7,


TABLE 1.

Mean Values* and Standard Deviations*
for Urinary Hormones

Altitude Epinephrine Norepinephrine 17-Ketogenic Steroids
(MSL) (ng/h) (ng/h) (mg/h)
Ground 575.2 1725.1 0.6959
Level +166.0 +386.3 +0.1361
8,000 651.3 1864.0 0.6014
Feet 4174.1 +526.5 40.1446
10,500 745.5 2100.6 0.6695
Feet +338.6 4642.4 £0.1322
12,506 797.1 2213.6 0.6918
Feet +386.1 £442.9 +0.2590
* N= 10

13