8 

Technical Report Documentatio 

1. Report No. 2. Government Accession No. 

FAA-AM-84 -4 

1 

4. Title and Subtitle 

AVIATION-RELATED CARDIORESPIRATORY EFFECTS 

OF BLOOD DONATION IN FEMALE PILOTS 

7. Author's) Michael T. Lategola, Audie W. Davis, Jr,, 

Ronald 0. Gilcher, Peggy 3. Lyne, and Mary 30 Burr 

9. Performing Organization Name ond Address 

FAA Civil Aeromedical Institute 

P.O. Box 25082 

Oklahoma City, Oklahoma 73125 9 I'---% pY 

9 

L.?, ,, $ :"' :-<i ,. !PSjl$ 28 ??% 

'OA opsoring Agency Name ond Address 

Ice of Aviation Medicine n r <, . 

Federal Aviation Administration n?*.j 

800 Independence Avenue, S .W. fhr:;? ~lv!iQ~jp;, 

Washington, D.C. 20591 lTm OF Tfi4;,:$c<R"dla RT&+ 

Work was done under approved task AM-A-82-PHY-130 

IS. Supplementory Notes 

3. Recipient's Cotalog No. no, - 

5. Report Date 

March 1984 

6. Performing Organization Code 

- 

8. Performing Organization Report No. 

10. Work Unit No. (TRAIS) 

11. Controct or Grant No. 

13. Type of Report and Period Covered 

OAM Report 

14. Sponsoring Agency Code 

16. Abstract 

ren healthy female pilots, 20-49 years old and weighing more than 110 pounds were 

ested for tolerances to'fiypoxia orthostatic stress, and physical work at 1 and 3 d 

fter donating ab.out 450 mL of blood on one occasion, and 6 mL (sham control) on a 

econd separate occasion, Testing included consecutive 30-min seated'exposures to 

ach of four oxygen-nitrogen mixtures' (.equal to air breathing at 6,000, 8,000, 10,000 

nd 12,400 ft of altitude), 5 min of quiet'standing, and seated pedal ergometry graded 

o produce a heart rate of 140 beats per min, At 1 d after blood donation as compared 

Q controls: functional incapacitation occurred in six subjects starting at 10,000 ft 

ltitude; psychomotor performance during hypoxPc exposure was decreased; transient 

rthostatic instability occurred; and, work capacity was decreased. At 3 d after 

lood donations as compared to controls: functional incapacPtation occurred in three 

ubjects. at the end of exposure to 10,000 ft altitude; psychomotor perfomance 

emained decreased; Orthostatic stability improved$ and, physical work capacity 

emained decreased. 

he findings of this study indicate that, in the complete absence of adyerse sypptoms 

t ground level, a pilot may return to flying between 1 and 3 d after blood donation 

ith the recommended initial precautions that: cabin altitude be limited to .( 6,000 

t (mean sea level); physical activity be minimized immediately before as we71 as 

wing flight; and +Gz stress exceeding the equivalent of short-duration level turns 

t .30 of bank angle be avoided, Until complete restoration of the pilot's in-flight 

iysiological tolerances has occurred, the presence of a copilot and on-board 

vailability of supplemental oxygen are also recommended, 

nvironment, Altitude Tolerance, +Gz through the National Technicai Information 

olerance, Physical Work Tolerance, Service,'Springfield, Yirginia 22161 

Icdical Standards, Medical Certiftcation, 

Liman Education xe-:, 

19. Security Classif. (of this report) 20. Security Clarrif. (of this page) 21. No. oCPoger 22. Price 

Unclassified Unclassified 31 
ACKNOWLEDGMENTS 

The authors acknowledge the valuable assistance of David Hehmeyer and Charles 

Valdez, Airman Education Section, in setting up and servicing the gasbreathing system used in this study. The authors also acknowledge the 

excellent and important contributions of Jymi Crabb, Elaine Moore, Mary Genzer, 

Ruth Cooksey, Meena Telikicherla, and Linda Chandler of the Sylvan N. Goldman 

Center, Oklahoma Blood Institute, Oklahoma City. The authors especially 

acknowledge the National Headquarters and the Oklahoma City Chapter of the 

"Ninety-Nines'' female pilot organizations for actively supporting this study by 

providing volunteer subjects from their membership. Jan Million and Lu 

Hollander were particularly instrumental in recruitment of subjects. Donna 

Fitzgerald is acknowledged for her valuable assistance in the preparation and 

typing of this report. 

iii 
LIST OF TABLES 

PaPe 

TABLE I. 

TABLE 11. 

TABLE 111. 

TABLE IV. 

TABLE V. 

TABLE VI. 

TABLE VII. 

TABLE VIII. 

TABLE IX. 

TABLE X. 

TABLE XI. 

TABLE XII. 

TABLE XIII. 

Experimental Protocol 

STAI Questionnaire 

(Preceding altitude) 

CHb and Hct Data 

Control Measurements 

Ground Level ( 1,300 f t MSL) 

SBP (torr) 

(During P&M test at altitude) 

DBP (torr) 

(During P&M test at altitude) 

PP (torr) 

(During P&M test at altitude) 

AP (torr) 

(During P&M test at altitude) 

HR (bpm) 

(During P&M test at altitude) 

P, (L/min BTPS) 

(During P&M test at altitude) 

HbO2 (% Saturation) 

(During P&M test at altitude) 

CaO 2 (mL/dL) 

(During P&M test at altitude) 

P&M Data 

Arithmetic Error Score 

Eye/Hand Coordination Error Score 

SBP (torr) 

DBP (torr) 

PP (torr) 

AP (torr) 

HR (bpm) 

Orthostatic Testing 

Orthostatic Testing 

Orthostatic Testing 

Pedal Ergometry Data 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

iv 
LIST OF ABBREVIATIONS 

BD 

THb 

BV 

G 

CHb 

MSL 

U.S. 

Hc t 

Hb 

GL 

SD 

OBI 

CAM1 

STAI 

ECG 

P&M 

HbO 2 

BP 

"E 

HR 

CaO 2 

W 

bPm 

SBP 

AP 

DBP 

PP 

COHb 

co 

DPG 

PI c 

PO2 

Blood donation 

Total circulating hemoglobin 

Blood volume 

Gravity 

Hemoglobin concentration 

Mean sea level 

United States 

Hematocrit 

Hemoglobin 

Ground level 

Sham donat ion 

Oklahoma Blood Institute 

Civil Aeromedical Institute 

State-Trait Anxiety Inventory 

Electrocardiogram 

Psychomotor and Mentation 

Oxyhemoglobin saturation 

Blood pressure 

Pulmonary ventilation 

Heart rate 

Arterial oxygen content 

Watts 

Beats per minute 

Systolic blood pressure 

Mean arterial pressure 

Diastolic blood pressure 

Pulse pressure 

Partial pressure of ambient oxygen 

Carboxyhemoglobin 

Carbon monoxide 

Diphosphoglycerate 

Pilot in command 

vlvi 

-- 

AVIATION-RELATED CARDIORESPIRATORY EFFECTS OF 

BLOOD DONATION IN FEMALE PRIVATE PILOTS 

INTRODUCTION 

The immediate effects of a typical blood donation (BD) are a decreased 

total circulating hemoglobin (THb), and a blood volume (BV) reduction of about 

450 mL. Because the donor's vulnerability to orthostatic intolerance in a +1G 

(gravity) environment is increased (28), it is logical that vulnerability to a 

+ +1Gz stress during in-flight aviation maneuvers should be even greater. 

Intravascular replenishment of the donated liquid volume in about 24-48 hours 

(5,241, which reduces vulnerability to orthostatic intolerance, generates a 

functional anemia by dilutional reduction of the hemoglobin concentration 

(CHb) (8,131. The CHb remains maximally reduced for about 2-7 d (10). Both 

the hypovolemia and anemia phases subsequent to BD are of potential 

aeromedical concern in general aviation pilots who may encounter transient 

in-flight exposures to > +1Gz, and cabin altitudes up to 12,500 ft (3,810 m) 

mean sea level (MSL) while breathing ambient air. 

The United States (U.S.) qualification criteria for donating a full unit 

(about 450 mL, nearly one pint) of blood are: minimum body weight of 110 

pounds for males or females; a CHb of +13.5 g/dL or a hematocrit (Hct) of 541 

percent for males; and, a CHb of 212.5 g/dL or a Hct of ~38 percent for 

females (9). The CHb and BV before donation (4,6,41), and the hemoglobin (Hb) 

regeneration rate after BD (13) are smaller in the average U.S. female than in 

the average U.S. male. In 1980, the average weight of U.S. female pilots was 

132.2 pounds and that of U.S. male pilots was 178.4 pounds (26). Blood volume 

is positively correlated with body weight (4,41), and the possibility of 

adverse effects of BD increases as the percentage of donated BV increases. 

Based on all of these considerations, this study focused initially on female 

pilots as subjects. The main purpose was to determine how soon such female 

pilots could return to flying after donating about 450 mL of blood. Assessment of effects at 1 and 3 d after separate donations of 6 mL (sham) of blood 

on one occasion, and about 450 mL on a second separate occasion, was based on 

each pilot's measured and subjective responses at ground level (GL) to hypoxic 

gas inhalation equivalent to breathing air at 6,000, 8,000, 10,000 and 12,400 

ft MSL of altitude, 5 min of quiet standing, and submaximum pedal ergometry. 

METHODS 

Subjects. The participants were 10 female pilots, 20-49 years old and 

prospective or full members of the "Ninety-Nines" pilot organization. After 

each subject underwent a briefing and signed a voluntary consent form, she was 

medically screened, and then trained for the experimental protocol as outlined 

in Table I. The subject was then scheduled to return for an identical experimental session at 1 and 3 d after either a sham donation (SD) or a BD. 
The means and standard errors of the subjects' ages, heights, and weights were 

38.1 +2.6 years, 65.8 +0.6 inches, and 137.5 +6.4 pounds, respectively. They 

had Ggged an average-of 358 flight hours aTid 6 years of flying. Medical 

certification was Class I1 for two of them and Class I11 for the remaining 

eight. Four subjects had previously donated blood, and three were currently 

smokers. 

Protocol and Measured Variables. After successful training, each subject 

was scheduled to return on a subsequent day for either an SD or BD. The BD's 

were done at the Oklahoma Blood Institute (OBI) in Oklahoma City. Each subject consented to be transported as a passenger to and from the OBI on the day 

of BD. The blood was drawn at 0900. The OBI provided concomitant measurements of CHb and Hct using Coulter methods (27); donated BV was calculated 

from the measured weight (in grams) of the donated blood and an assumed 

density of 1.053 g/mL (27). The SD's and all other experimental sessions were 

conducted at the Civil Aeromedical Institute (CAMI) in Oklahoma City. To 

minimize CHb and Hct variability related to postural and activity changes 

(171, all blood samples were drawn after a minimum of 20 min of seated rest. 

In the two experiments, each subject underwent an assessment protocol at 1 

and 3 d after the SD or the BD. To preclude order effects, half of the subjects underwent BD in the first experiment, and the remaining half underwent 

it in the second experiment. The pooled data were statistically compared 

according to Student's paired t-test (35) on the basis of SD versus BD at 1 

and 3 d after donation. Statistical significance was based on a probability 

value of ~20.05 (35). To assure complete restoration of the Hb lost in the BD 

(26), each subject's BD and SD were separated by a minimum of 8 weeks. 

The postdonation assessment protocol is outlined in Table I. For the 1 d 

assessment, each subject ate breakfast prior to arriving at 0830. The subject 

initially provided information regarding the first 16 hours (up to bedtime) 

after SD or BD. This consisted of her reporting the presence/absence of unusual degrees of mental fatigue, physical fatigue, and orthostatic intolerance; 

whether or not she thought that her piloting ability had been compromised to 

an unsafe degree; and, whether or not she would have piloted an aircraft during this time and, if so, would she have unusually limited her altitude, 

flight duration, +Gz maneuvers, and/or flown without a copilot. Next, she was 

asked for the same information pertaining to the morning of 1 d after SD or BD. 

The subject's body temperature and general health were checked. She 

filled out the State-Trait Anxiety Inventory (STAI) questionnaire (37) to 

assess her "right now" anxiety state. A 6 mL venous blood sample was then 

drawn for measurement of CHb and Hct using Coulter and microhematocrit centri- fuge techniques, respectively (27). The subject donned a surgical scrub suit, 

and electrodes were attached to her chest for recording a CM5 single-lead 

electrocardiogram (ECG) (3). After the subject voided urine, her weight was 

measured. She was seated in a comfortable chair and given a writing board. 

Next, she took the combined psychomotor and mentation (P&M) test as a learning 

refresher. This test consisted of 20 pages of simple addition and subtraction 

problems to be answered true or false by using a checkmark in eaeh appropriate 

answer block. The arithmetic score equaled the product of the number of 

incorrect answers and the time (min) for test completion. The eye/hand 

2 
coordination score equaled the product of block boundary violations and time 

(mid for test completion. 

After again voiding urine for comfort's sake, th.e subject was reseated for 

the remaining 3 h of testing. At this time, an oximeter sensor was placed on 

the subject's right ear for measuring oxyhemoglobin saturation (Hb02) (25,321, 

a blood pressure (BPI cuff was placed on her right arm, and the ECG cable 

connected to its recorder. Eight minutes of control measurements were obtained 

at this time. An oronasal mask was then donned by the subject and she began 

consecutive 30-min exposures to separate oxygen-nitrogen mixtures equal to air 

breathing at 6,000, 8,000, 10,000 and 12,400 ft altitude. The subject took one 

timed P&M test startingeat the 10th min of each altitude. Mean values of 

pulmonary ventilation (Vg), Hb02, and heart rate (HR) were obtained from 

continuous recordings durlng the entire P&M test. The iE was measured by a 

flow transducer in the inspiratory circuit. The BP measurement representing 

each P&M test period was obtained at the completion of the test. The mean 

value for arterial oxygen content (Ca02) during each P&M test was obtained by 

multiplying the concomitant mean HbO2 by.CHb x 1.34 (31). 

Before and after each P&M test,~the subject answered a checklist of 

questions regarding the possible presence and degree of adverse symptoms. 

During training, each subject had been taught simple hand signals tc 

facilitate communication while wearing the mask. Each subject had the 

unconditional option of terminating hypoxic exposure by lifting the mask off of 

her face. A staff physician and emergency resuscitation 'equipment were 

available on a standby basis. 

After completion of simulated altitude exposure, and removal of the 

subject's mask and Hb02 sensor, suitable recovery and additional control 

measurements preceded the orthostatic test of 5 min of quiet standing. After 

this test and adsitional control measurements, the subject redonned the mask 

(for measuring VE>, and underwent pedal ergometry at a starting load of 30 

watts (W) for 1 min. The load was increased 5 W per min up to 75 W, which was 

sustained for 5 min. The test was terminated at this maximum load or earlier, 

if and when an HR of 140 beats per min (bpm) was reached, or limiting symptoms 

occurred. The ECG, HR, and BP were measured during both the quiet standing and 

ergometry tests. After monitored recovery, the subject redonned her street 

clothes and underwent a comprehensive interview to assess all encountered 

subjective symptoms that might be potentially adverse to flight safety. She 

was also asked to evaluate the presence and degree of any decrements in her 

piloting safety associated with the SD or BD. The subject was then scheduled 

to return 2 d later for an identical experimental session. 

Temperature and relative humidity ranges in the experimental room during 

the whole study were 22.0-24.5O and 43.0-50.0 percent, respectively. 

Because appreciable reductions in CHb and Hct may persist for more than 

3 d after BD (33,391, each subject was asked to return 7 d after BD for 

measurement of CHb and Hct. Eight subjects complied with this request. Also, 

each subject was asked to report all piloting done within 3 weeks after BD. 

Data of particular interest "were altitudes, flight durations; >+1Gz maneuvers, 

and the presence of any s'ymptoms which could compromise sa.fety. 

3 
RESULTS 

As calculated from measured height and weight data (41, the subjects’ mean 

predonation BV (and standard error) was 3,742.8 2124.4 mL. The mean volume of 

donated blood was 460.123.4 mL. The BD’s constituted a mean of 12.4 20.4 

percent of the predonation BV‘s. 

STAI data, which assessed mood state preceding altitude exposure, are 

summarized in Table 11. Only the depression - dejection mood state showed a 

statistically significant mean increase 1 d after BD as compared to SD. No 

significant differences were present at 3 d after BD. 

Table 111 summarizes the CHb and Hct data. The CHb and Hct mean 

decrements at 1 and 3 d, and at 7 d after BD were statistically significant, 

and those at 7 d were less than the corresponding values at 3d. 

Table IV summarizes initial control cardiovascular data obtained at GL 

(1,300 ft MSL). Although the mean values of these five variables at 1 and 3 d 

after BD were lower than the corresponding values after SD, only those of the 

systolic BP (SBP) were statistically significant. 

Simulated Altitude Exposure. One day after BD, six subjects became 

functionally incapacitated during altitude exposure. One incapacitation 

occurred at the start and one at the end of exposure to 10,000 ft altitude, and 

the remaining four during the first 10 min at 12,400 ft. Three days after BD, 

three of these same six subjects became incapacitated during altitude exposure. 

One incapacitation occurred at the end of exposure to 10,000 ft altitude, and 

the remaining two at 12,400 ft. For this study, functional incapacitation was 

defined as definite hypoxia symptoms approaching loss of consciousness. In the 

1 and 3 d assessments after SD, hypoxia symptoms were absent in seven of the 

subjects. The remaining three subjects showed minor symptoms, and these only 

at 12,400 ft. Of these three, two were among those who became incapacitated 

during the experimental altitude exposures after BD. 

Tables V-VI11 summarize the cardiovascular data obtained during the P&M 

tests of the first three altitudes. The corresponding data for 12,400 ft were 

not statistically analyzed because sufficient pairs of data were unavailable 

due to preceding incapacitations at that altitude. As these tables show, 

statistically significant mean decrements occurred in SBP, mean arterial 

pressure (AP), jE, and Ca02 as compared to the corresponding data after SD. 

Excepting CaO2, 8,000 ft appeared to be the general altitude threshold for 

significant cardiorespiratory decrements after BD. This altitude threshold for 

significant cardiorespiratory decrements was generally correlated with the 

concomitant onset of hypoxia symptoms after BD. 

Symptoms During Simulated Altitude Exposure. One day after BD, three 

subjects reported drowsiness onset at the end of exposure to 6,000 ft altitude. 

At 8,000 ft all subjects showed drowsiness along with varying degrees of 

yawning, stretching, and restlessness. During the P&M test at this altitude, 

visual focusing difficulty began in two subjects, and mental concentration 

began to deteriorate in nine subjects. At l0,OOb ft, drowsiness intensified, 

and began to include short periods of eyelid droopiness/closing in all 

4 
subjects; some head droopinglbobbing occurred in five subjects, and headache 

onset in one subject; visual difficulty commenced in three others. The two 

subjects who became incapacitated at 10,000 ft experienced progressive 

presyncopal visual symptoms of blurring, graying, and tunneling. At 12,400 ft, 

drowsiness and deterioration of mental concentration showed further 

intensification in the remaining eight subjects. Of the four subjects who 

became incapacitated at this altitude, one experienced the progressive visual 

symptoms of presyncope, and the remaining three approached loss of 

consciousness via an overpowering sleepiness. Despite the presence of hypoxia 

symptoms in the remaining four subjects, they were able to complete the 30-min 

period at 12,400 ft. Although these four subjects were not incapacitated, they 

reported retrospectively that their estimated safety margins as pilots had been 

definitely reduced. They reported that, in the event of such symptoms in 

,. ~~ght, supplemental oxygen and/or decreased altitude would have been used 

until all the symptoms disappeared. 

i” 

Three days after BD, symptom onset did not occur until 8,000 ft. At this 

altitude, drowsiness along with restlessness and yawning started in six 

subjects, a decrease in mental concentration commenced in five subjects, and 

visual difficulty began in one subject. At 10,000 ft, drowsiness was present 

in nine subjects, with eyelid drooping/closing and head drooping starting in 

five of them. Visual difficulty was present in four subjects, and decreased 

mental concentration was present in all subjects and intensifying at individual 

rates. One subject became incapacitated at this altitude due to overpowering 

sleepiness. At 12,400 ft, intensified drowsiness and decreased mental 

concentration were present in all subjects, and visual difficulty was present 

in five of them. The two subjects who became incapacitated were unable to 

withstand the intense sleepiness which was approaching loss of consciousness. 

The remaining seven subjects reported retrospectively that, although their 

symptoms felt less severe than at the same altitude 1 d after BD, they were 

severe enough to cause some reduction in estimated margins of piloting safety. 

P&M Performance During Simulated Altitude Exposure. Table IX summarizes 

the P&M mean scores of the first three altitudes. The corresponding data for 

12,400 ft were not statistically analyzed because of insufficient data due to 

the preceding incapacitations. As indicated by the mean scores in Table IX, 

both the arithmetic and eye/hand coordination performances at each altitude 

were decreased at 1 and 3 d after BD as compared to 1 and 3 d after SD. 

Npwever, only one of the mean score differences for eye/hand coordination 

PITQ~S was statistically significant. 

Orthostatic Tolerance. Tables X-XI1 summarize the cardiovascular data from 

the control period, and the ensuing 5 min of quiet standing. During the 

control period, the mean values of SBP, diastolic BP (DBP), pulse pressure 

(PPI, and AP at 1 and 3 d after BD were lower than the corresponding values 

after SD. However, only the SBP decrement at 1 d after BD was statistically 

significant compared to the corresponding value after SD. During the first and 

fourth min of quiet standing, the mean values of the four BP variables were 

lower at 1 and 3 d after BD (except PP at 3 d) than the corresponding mean 

values after SD. However, only the decrements in the first- min mean values 

of SBP and AI? at 1 d after BD were statistically significant. Although the 

mean HR’s during quiet standing were higher at 1 and 3 d after BD than at 1 and 

3 d after SD, the differences at 3 d were less than at 1 d. None of the mean 

BB differences between SD’s and BD‘s were statistically significant. 

5 
SYmPtoms Burina Orthostatic Testinq. One day after BD, four subjects 

reported transient symptoms during the first 10 s of quiet standing. Shaky 

unsteadiness was the main symptom in two subjects, lightheadedness in the third 

one, and a lightheaded flushed feeling in the fourth. One subject, devoid of 

symptoms during the standing test, experienced transient severe lightheadedness 

upon standing after 8 min of seated recovery from pedal ergometry. 

Three days after BD, residual unsteadiness occurred in the same two 

subjects upon standing, but of much less severity and duration than at 1 d 

after BID. Symptoms were absent from all subjects during t h e q u i e t standing 

test at 1 and 3 d after SB. 

Pedal Ergometry. The pedal ergometry data are summarized in Table XIII. 

The mean values for total pedaling work (W x min) achieved at 1 and 3 d after 

BD were much less than the corresponding mean values achieved at the same HR 1 

and 3 d after SD. Both the 1 and 3 d work decrements were statistically 

significant. This finding is. consistent with that of Balke et al. (1). 

Although the mean values for VE and HR during isoload pedaling at 1 and 3 d 

after BD (Table XIII) were greater than the corresponding values measured at 

the same total workload at 1 and 3 d after SD, only the HR increments were 

statistically significant. Valid BP measurements were not attainable during 

pedal ergometry because high noiselsignal ratios obliterated the Korotkov 

sounds e 

Svmptoms During Pedal Ergometry. Although the total pedaling work 

achieved at the same HR by the subjects at 1 d after BD was significantly less 

than at 1 d after SD, fatigue symptoms in six of the subjects were greater 

during ergometry after BD than after SD, These six subjects reported leaden 

heaviness in their legs during pedaling, deeper and harder breathing with 

shortness of breath, and intense physical fatigue nearing its subjective limit 

at the end of the test. Symptoms receded slowly during recovery. 

Three days after BD, these same six subjects reported similar and less 

intense symptoms than at 1 d after BD, but the symptoms were still greater than 

those during ergometry at 1 and 3 d after SD. 

SUPPLEMENTAL SUBJECTIVE REPORTS 

Symptoms Within 16 h After BD. Symptoms relatable to BD were those which 

were present after BD, but not after SD. One subject, who had no adverse 

symptoms during BD or upon standing immediately thereafter, almost fainted 15 

min after leaving the Blood Donation Center. She experienced sudden severe 

lightheadedness upon quiet standing immediately after running a very short 

distance from her car into a post office. She immediately squatted (to reduce 

hydrostatic height), and remained thus until the symptoms disappeared. She 

abandoned her errand and returned cautiously to the car for additional seated 

recovery 

During the first 16 h after BD, three subjects experienced considerable 

sluggishness and fatigue in mentation. Two of these same three subjects plus 

6 
three others reported unusual degrees of physical fatigue described as 

slowness, inertia, leaden heaviness, and lassitude. Both mental and physical 

fatigue were still present at bedtime. Repeated lightheadedness (upon 

standing) which occurred in three subjects, tapered off by bedtime. Based on 

self - appraisal of symptoms, two subjects would not have flown at this time 

because they felt unsafe as pilots, two would have flown only if accompanied by 

a copilot, one was indecisive, and the remaining five felt that they could have 

flown safely as solo pilots, None of the subjects actually flew during this 

period. 

Svmptoms at Id After BD. Preexperimentally, slight residual physical 

fatigue and inertia were reported by two subjects, residual mental sluggishness 

by a third subject, and lightheadedness upon first arising by a fourth subject. 

One of these four expresse reservations about her safety to fly at this time, 

but would have done so in the next 4 h if accompanied by a copilot. The 

remaining nine subjects felt that their current mental and physical conditions 

were fully compatible with safe solo flight in the next 4 h. 

Svmptoms at 3 d After BD. Preexperimentally, all subjects reported the 

absence of adverse mental symptoms and ,lightheadedness. Two subjects reported 

slight residual physical sluggishness. These two subjects said that they would 

have flown in the next 4 h, but only in the presence of a copilot and at less 

than 8,000 ft altitude. The remaining eight subjects judged their mental and 

physical conditions to be fully compatible with safe solo flight in the ensuing 

4 h. 

Anecdotal I n - Flight Information. Five subjects did some flying with 

copilots within 3 weeks after BD. Pertinent information from these flights is 

summarized in Appendix A. 

DISCUSSION 

Altitude Tolerance 1 d After BD. One day after BB, hypoxia -related 

symptoms started in three subjects at 6,000 ft. The incapacitation of two 

subjects occurred at 10,000 ft and four more at 12,400 ft. Although the 

remaining four subjects were not incapacitated, they were definitely impaired 

by severe drowsiness and decreased mental concentration. Although statistical 

significance was mostly absent in the P&M data (Table 1x1, they uniformly 

reflected mean decreases in psychomotor function at all altitudes. Tpe 

altitude threshold for statistically significant decrements in SBP, AP and VE 

(Tables V-VI19 coincided with definite establishment of hypoxia symptoms in all 

10 subjects. The most prevalent major symptoms were drowsiness and decreased 

mental concentration. Although some subjects tried to partially ascribe their 

hypoxic drowsiness to boredom, all readily admitted that all adverse symptoms, 

including drowsiness, rapidly disappeared after removal of the mask. In all 

cases, symptom disappearance paralleled the rise of the Bb02 back to the higher 

GL values. This pattern of drowsiness was absent from all simulated altitude 

exposures after SD. Without prior BD, drowsiness is known to occur commonly as 

a symptom of altitude hypoxia (21,29,40), but it usually commences at higher 

altitudes than those simulated in this study. 

7 
The mean values of CaO2 (Table VIII) at each altitude reflected the 

decreased level of arterial oxygenation at 1 d after BD as compared to 1 d 

after SD. As reflected in Table 111, the mean CHb was nearing its minimum 

value at this time. The Ca02 reductions are consistent with the increased 

vulnerability to hypoxia at increasing altitudes. 

When drowsiness and decreased mental concentration reached appreciable 

levels during altitude exposure after BD, the subjects reported that these 

symptoms increased and decreased in an oscillating manner. From then onward, 

it was consistently observed that increasing HR and drowsiness symptoms and 

decreasing mental concentration were preceded by decreasing ventilation and 

HbO2, and a reversal of this pattern was preceded by increasing ventilation and 

Hb02. This oscillatory pattern was present in all subjects after BD at the 

threshold altitude of 8,000 ft. The amplitude and frequency of oscillation 

became greatest in the six subjects who subsequently became incapacitated. 

Because hypoxia effects were absent during simulated altitude exposure 

after SD, the effects observed after BD are logically relatable to a combined 

effe,ct of reduced CHb and residual hypovolemia. Assuming that the initially 

diminished THb remains constant at 1 d after BD (361, then the 

predonation/postdonation ratios of CHb and Hct can provide a percentage 

estimate of BV restoration. Calculated in this manner, mean BV 1 d after BD 

approximated 95 to 97 percent of predonation values. This estimate is 

consistent with those of other studies (5,241. Therefore, the hypoxia effects 

observed at 1 d after BD were mainly relatable to the decre2sed CHb. 

The four subjects who were impaired but not incapacitated during 

altitude exposure after BD manifested the highest predonation CHb values. The 

two highest values (14.8 and 15.9 g/dL) were those of the two heavy cigarette 

smokers. The nonincapacitation of these two subjects at 12,400 ft would not be 

anticipated if the usual elevated carboxyhemoglobin (COHb) levels found in 

heavy smokers (38) were present, but upon cessation of smoking, the half-life 

washout of carbon monoxide (CO) from the blood's COHb is about 3-5 h (22). 

Smoking by each subject was forbidden from 0830 until completion of all 

testing. Altitude exposure usually occurred between 1030-1230. Therefore, any 

dissociation and washout of CO from the blood's COHb up to 1230 must have 

increased the amount of Hb available for additional oxygenation and support of 

altitude tolerance. Quantitation of this effect in these two smokers was not 

possible, because COHb was not measured at 0830 and 1230. 

The unsteadiness or lightheadedness in four subjects at the onset of 

the quiet standing test 1 d after BD reflected a residual effect of 

hypovolemia. Additional plasma volume losses probably occurred during the 2-3 

h of sedentary testing preceding the standing test (23). 

If blood loss is not rapid and amounts to less than 20 percent of the 

initial BV, compensatory reflex increases in cardiac contractility, HR, and 

arterial vasoconstriction (7,161 usually suffice to sustain useful 

consciousness under upright resting conditions (11,141. However, as evidenced 

by the near-syncope incident of one subject about 15 min after BD, the "opening 

up"of the circulation by a short bout of exercise can overwhelm the ability of 

the compensatory cardiovascular ref lexes to maintain cerebral perfusion around 

the time of maximum hypovolemia. Even without prior BD, fainting'due to postexertional blood pooling in the standing position can occur (12,341. 

8 
After BD, because volume restoration dilutes the CHb, some reflex 

cerebral and coronary vasodilation is necessary to maintain cerebral and 

myocardial oxygenation (7). However, any such vasodilation must be 

counterbalanced by peripheral arterial vasoconstriction in order to maintain 

the hydrostatic pressure required for cerebral perfusion (7). Although this 

integrated control is readily achieved at GL under resting normoxic conditions, 

the superimposition of altitude hypoxia can impair and overwhelm this 

delicately balanced compensatory mechanism (18,191 and, in some instances, do 

it suddenly (2). The incapacitations which occurred during altitude exposure 

1 d after BD were most likely precipitated by the inadequacy of this 

compensatory mechanism to maintain cerebral perfusion. The preceding small but 

significant mean decrement in SBP and AP (Tables V and VI11 were consistent 

indications of this decompensation. Reflex compensatory increases in HR and 

9, (Table VI11 did not occur. It is possible that the internal s stems 

ordinarily responsible for hypoxically stimulated increases in HR and were 

depressed at this time. However, no direct evidence was obtained in this study 

to support or deny this possibility. Therefore, the combination of reduced CHb 

and residual hypovolemia definitely compromised altitude tolerance starting at 

Altitude Tolerance 3 d After BD. Three days after BD, hypoxia symptoms 

started in all subjects during the 8,000 ft altitude exposure. By 12,400 ft, 

three subjects had become incapacitated, and the remaining seven were impaired 

but not incapacitated. Statistically significant decrements in SBP and CaO2 

(Table V and VIII) persisted at 3d after BD. 

8,000 ft. 

The group's general improvement in altitude tolerance 3 d after BD 

appears paradoxical to the further decreases in CHb and Hct (Table 1111, and 

the persistent decrease in b, (Table VII). However, because erythropoiesis 

is probably starting to increase 3 d after BD (391, the decreased CHb could 

have reflected a plasma volume increase beyond its predonation level (30). An 

increased THb along with a slight hypervolemia could have increased cerebral 

oxygenation and improved .hydrostatic protection. of cerebral perfusion during 

altitude exposure. Although not statistically significant, the slight but 

consistent increase in HR at 3 d after BD as compared to SD (Table VII) could 

have helped to increase cerebral perfusion. In addition, an increased 

intraerythrocytic 2,3-diphosphoglycerate (DPG) is capable of enhancing tissue 

oxygenation by shifting the oxyhemoglobin dissociation curve to the right (5). 

The degree of these possible effects is conjectural. Although altitude 

tolerance had generally improved 3 d after BD, altitude tolerance was still 

impaired starting about halfway through exposure to the 8,000 ft altitude. 

Altitude Tolerance 7 d After BD. The mean CHb and Hct decrements at 

7 d were less than at 3 d after BD. At 7 d after BD, one can conservatively 

assume that normovolemia is present, and that appreciable increases in 

erythropoiesis (30) and 2,3-DPG (5) have occurred. The anecdotal flight data 

(Appendix A) suggest that altitude tolerance continued to improve at 7 d after 

BD. Whether or not altitude tolerance had completely returned to predonation 

levels remains an open question. 

Predicted Versus Actual Performance at Simulated Altitude. One and 

three days after BD, a total of three subjects predicted that they would be 

unsafe pilots above 8,000 ft, because of residual presence of adverse symptoms 

at GL. These predictions proved to be valid, for these subjects were among 

9 
those who became incapacitated during altitude exposure. Therefore, after BD, 

if mental and/or physical symptoms are residually present at GL, these effects 

will most probably be dangerously accentuated in the donor/pilot at some 

altitude of ,lO,OOO ft while breathing ambient air. 

Conversely, in the rest of the subjects, the absence of residual 

symptoms at GL was not a valid predictor of adequacy of altitude tolerance. 

Prior to altitude testing at 1 and 3 d after BD, these subjects predicted that 

they could fly safely as solo pilots. During the subsequent altitude testing, 

all of them became impaired or incapacitated. Retrospectively, all of them 

concurred that their estimated flight safety margins had been significantly 

reduced. 

Although the depression-dejection mean mood score was significantly 

increased at 1 d after BD, the individual scores were very poor predictors of 

subsequent adequate/inadequate altitude tolerance. 

Currently, it is not apparent what GL self-test the donor pilot could 

apply in order to determine her physiological readiness to return to flying. 

Because the pedal ergometry data (Table XIII) showed that a significant 

decrement in work capacity remained at 3 d after BD, it is possible that a 

preflight exercise test self-imposed by the donor/pilot might provide useful 

subjective sypmtomatic information. Since the Ca02 data (Table VIII) still 

showed significant decrements at 3 d, it is possible that restoration of full 

altitude tolerance parallels the return of CHb towards its predonation level. 

However, if altitude tolerance remains predictively uncertain, the donorlpilot 

(and especially the heavy smoker) should be fully prepared to use supplemental 

oxygen at lower than usual altitudes. Heistad et al. (18) have shown that the 

hypotensive effects of altitude and hypovolemia combined can be prevented or 

reversed by supplemental oxygen. 

Orthostatic Tolerance 1 d After BD. After BD, the occurrence of 

adverse symptoms and/or cardiovascular decrements upon quiet standing must 

logically be construed as an increased risk of intolerance to >+lGz loads 

incurred in flight. At 1 d after BD, the transient symptoms and significant 

SBP and AP decrements (Tables X and XI) at 1 min of quiet standing reflect this 

increased +Gz vulnerability. The severe lightheadedness in the one subject 

upon standing after recovery from pedal ergometry indicates an even greater +Gz 

vulnerability under vasodilated conditions. Although the donors' BVs at 1 d 

after BD were probably nearing repletion, the 2-3 h of sedentary testing which 

preceded the standing test could have caused further dependent extravasation 

losses of plasma volume (22). This type of +Gz vulnerability should increase 

as a function of flight duration. Flights of 2-3 h duration are fairly common. 

As anecdotally reported in Appendix B, one "Ninety-Nines" member (not 

in this study) piloted a flight 1 d after BD. Her flight included a symptomfree short-duration turn at a 30' bank angle (about +1.2Gz). 

Orthostatic Tolerance 3 d After BD. The improvement in the subjects 

orthostatic tolerance (standing test) at 3 d after BD was consistent with the 

calculated estimate that total volume repletion had occurred. This is 

consistent with the previous findings of Green et al. (15). Anecdotal 

information (Appendix A) indicated that, from 2 d after BD and onward, several 

10 
subjects executed prolonged in-flight turns at a 30° bank angle without adverse 

symptoms. One subject reported that, at 9 d after BD, transient 

lightheadedness occurred at the start of her execution of 720" right and left 

turns at a 45' bank angle. Therefore, at 3 d after BD, +Gz tolerance had 

probably improved enough to include (symptom-free) in-flight turns at bank 

angles of >30° but <45O (about +1.4Gz). 

Physical Fatigue Tolerance at 1 and 3 d After BD. Since the estimated 

mean BV was nearing repletion at 1 d after BD, and was fully repleted at 3 d 

after BD, the significant decrements in mean total pedaling work (Table XIII) 

were probably mainly related to the concomitant decreases in mean CHb (Table 

111). This is consistent with the CaOq data in Table VIII. The work 

decrements shown in Table XI11 are consistent with those reported by Woodson et 

al. (42) in subjects with isovolemic anemia. The increase in the 

arteriovenous oxygen difference, which usually accompanies an increasing 

physical workload, was obviously limited by the already lowered preergometry 

Ca02. Therefore, because cumulative fatigue could adversely affect psychomotor 

performance and altitude tolerance, prior workloads should be avoided if the 

donor has to pilot an aircraft 1-3 d after BD. If the donor/pilot has rested 

prior to flight, but incurs an appreciable mental and/or physical workload 

during flight, then use of supplemental okygen may be beneficial. 

Performance Decrement Prior to 1 d After BD. The presence of adverse 

symptoms at GL 1 and 3 d after BD was a consistent predictor of subsequent 

altitude intolerance. Despite general curtailment of physical activity by all 

the subjects during the first 16 h after BD, six of them experienced 

considerable degrees of mental, physical, and/or orthostatic adverse symptoms. 

Restoration of the vascular liquid volume at 8 h after BD can be as variable as 

25 to 75 percent (5,11,20). The occurrence of adverse altitude and orthostatic 

reactions at 1 d after BD, in spite of the near repletion of BV, logically 

suggests that, up to 8 h after BD, such adverse reactions should be greater in 

number and degree. Therefore, piloting an aircraft within 8 h after BD, in the 

prior presence of adverse symptoms at GL, is strongly contraindicated. The 

presence of such symptoms up to 16 h after BD should continue to contraindicate 

piloting by the donor. Similar to 1 d after BD, the complete absence of 

adverse symptoms at GL up to 16 h after BD cannot predictively guarantee 

adequate altitude tolerance in flight. 

CONCLUSIONS 

Compromise of physiological functions starts immediately after BD of 

about 450 mL of blood. The initial concern is hypovolemia, which is manifested 

primarily as an increased vulnerability to orthostatic (+Gz) intolerance. This 

initial vulnerability is accentuated if the circulation is "opened up" by prior 

physical activity. As the liquid volume is restored, vulnerability shifts away 

from orthostatic intolerance towards all oxygenation functions which are 

vulnerable to acute decreases in CHb. This vulnerability reaches its peak at 

full restoration of BV when the maximum dilutional reduction of CHb has 

occurred. From that time onward, as erythropoiesis increases the CHb towards 

it predonation level, the remaining vulnerability recedes. 
Up to 16 h after BD, the presence of appreciable mental and/or physical 

adverse symptoms at GL contraindicates piloting by the donor. Conversely, the 

complete absence of adverse symptoms at GL up to 16 h after BD cannot guarantee 

adequate altitude tolerance by the donor. 

Between 1 and 3 d after BD, the residual presence of adverse mental 

and/or physical symptoms at GL remains a contraindication to piloting by the 

donor. However, in the complete absence of adverse symptoms at GL, a pilot may 

return to flying between 1 and 3 d after blood donation with the 

recommended initial precautions that: cabin altitude be limited to 5 6,000 ft 

(mean sea level); physical activity be minimized immediately before as well as 

during flight; and +Gz stress exceeding the equivalent of short-duration level 

turns at 30' of bank angle be avoided. Until complete restoration of the 

pilot's in-flight physiological tolerances has occurred, the presence of a 

copilot and on-board availability of supplemental oxygen are also recommended. 

Because the patterns and rates of recovery after BD manifest large 

individual degrees of variability, each donor should continue to use the 

recommended precautionary measures until all adverse residual symptoms both at 

GL and at altitudes up to 12,500 ft have disappeared. The disappearance of inflight symptoms should parallel the rebound increase in CHb, which usually 

begins 3-7 d after BD. 

Because males generally have greater predonation BV's and CHb's than 

females, both the maximum degree of adverse symptoms after BD and the minimum 

time for adequate recovery should be less in the former than in the latter. 

However, each male donor/pilot should also use the same recommended initial 

precautions when returning to flying, and decrease the precautionary measures 

in accordance with the disappearance rate of his individual adverse symptoms. 

12 
APPENDIX A 

One subject flew at 3,500 ft for 45 min as PIC 7 d after BD. During 

flight, she executed two right and two left 360' turns at a 30° bank angle 

without adverse symptoms. 

One subject flew at 8,500 ft for 75 min as copilot 11 d after BD. A 

headache developed after 20 min at that altitude, lasted for the rest of the 

flight, and disappeared spontaneously within 15 min after landing. She 

reported that this type of headache and its total pattern had never happened to 

her on any other flight. She flew the 75-min return flight as PIC on the next 

day at 5,500 ft without adverse symptoms. 

One subject flew three separate times as PIC within 9 d after BD. Her 

first flight on the fourth day was at 5,500 ft for 50 min, and she incurred no 

adverse symptoms. Her second flight on the sixth day was flown at 4,500 ft for 

50 min without adverse symptoms. In this flight, she executed a short-duration 

30' bank after takeoff. Her third flight on the ninth day was flown with an 

instructor pilot at 4,000 ft for 45 min. In this flight she executed one right 

and one left 720' turn at a 45' bank angle. She reported that transient 

lightheadedness occurred at the start of each turn and disappeared in about 5 s 

as each turn was sustained. She reported that in all her piloting preceding BD 

she had never experienced lightheadedness at the start of any turn at a 45' 

bank angle. 

The fifth subject flew with her husband on three separate occasions 

within 6 d after BD. Her first flight, a round trip between Oklahoma City and 

Phoenix, Arizona, took place between 45 and 60 h after BD. After a morning 

takeoff by her husband, she took over as PIC for the 3-h leg to Albuquerque, 

New Mexico, at an altitude of 10,000 ft. At this altitude, she experienced 

some visual focusing difficulty and lightheadedness, which was relieved by 

intermittent use of supplemental oxygen. During descent for landing at 

Albuquerque, these symptoms disappeared. On the 2-h leg to Phoenix, she flew 

as copilot. Her lightheadedness and vision symptoms reappeared at about 11,000 

ft during climbout. Starting at 12,000 ft, she reinstituted intermittent use 

of oxygen for the remainder of the flight. Her symptoms were relieved during 

oxygen use, and disappeared during descent for landing at Phoenix. The return 

flight started at 1700, and was flown nonstop to Oklahoma City. After climbout 

and leveling off at 12,000 ft, she took over as PIC. Shortly thereafter, when 

hypoxia symptoms began and intensified to a noticeable degree, she started 

intermittent use of oxygen. Her symptoms of lightheadedness, instrument 

disorientation, and difficulty with maintaining visual concentration came and 

went in an oscillating fashion. Her vision was clear but, during instrument 

scanning, individual gauges sometimes appeared to be "swirling." Although this 

pattern of symptoms persisted all the way to Albuquerque, she did not consider 

the maximum symptom level to be severe. Each time she used oxygen, the 

symptoms abated. As she neared Albuquerque, temporarily off of oxygen, she 

experienced a frightening rapid onset and intensification of visual blurring 

13 
that transitioned into graying and tunneling. Her immediate use of oxygen 

reversed these symptoms. She reduced altitude to 11,000 ft, and shortly 

thereafter to 9,000 ft for the rest of the flight into Oklahoma City. All 

symptoms disappeared at 9,000 ft, and she subsequently made an uneventful night 

landing at Oklahoma City. During the many times that she had made this roundtrip flight, she had never experienced hypoxia symptoms. 

Four days after BD, this subject copiloted a 4.5-h flight to Corpus 

Christi, Texas. Flight altitudes were 6,000 ft for 1.5 h and 10,000 ft for 3 

h. Six days after BD, she copiloted t h e r e t u r n flight from Corpus Christi to 

San Antonio at 4,500 ft, and piloted the remaining 3-h leg to Oklahoma City at 

9,000 ft. In both flights she experienced no hypoxia symptoms. 

14 
APPENDIX B 

Anecdotal Flight Information. One "Ninety-Nines" pilot (not in this 

study) reported flying 1 d after BD. Her CHb prior to BD was 15.1 g/dL, and 

her donated BV was estimated at 10.3 percent of her predonation BV. She flew 

as PIC for 1.5 h at an altitude of 4,500 ft. She executed one short-duration 

turn at a 30' bank angle. No adverse symptoms occurred during tnis flight. 

15 
TABLE I. 

Experimental Protocol 

Time (min) Activity 

0 (0830) 

0- 90 

90-100 

100 

100-130 

130-160 

160-1 90 

190-220 

220 

220-230 

23 0 

230-23 8 

23 8- 243 

243-250 

250 

250-255 

255-26 9 

26 9- 27 9 

280- 

Subject arrival 

Preexperimental interview 

Health check 

STAI questionnaire 

Venous blood sample 

Body weight 

Subject instrumentation 

P&M refresher test 

Prealtitude control measurements 

Start of altitude period 

6,000 ft a’hti,tv;de expsaure 

PbH test $1 

8,000 ft altitude exposure 

P&M test 12 

10,000 ft altitude exposure 

P&M test #3 

12,400 ft altitude exposure 

PbM test 84 

End of altitude period 

Recovery period 

Start of orthostatic test period 

Seated control measurements 

Quiet standing period 

Seated recovery period 

Start of pedal ergometry period 

Seated control measurements 

Pedal ergometry 

Monitored recovery 

Postexperimental interview 

STAI = State-trait anxiety inventory 

P&M = Psychomotor and mentation 

16 
TABLE 11. 

STAI Questionnaire 

(Preceding altitude) 

SD + Id BD + Id 

2.1 

0.7 

1.2* 

0.4 

0.2 

0.1 

22.7 

1.7 

1.0 

0.7 

2.3 

0.4 

SD + 3d 

2.0 

0.5 

0.2 

0.1 

0.2 

0.1 

20.8 

2.2 

0.9 

0.7 

1.9 

0.3 

BD + 3d 

1.9 

0.5 

0.6 

0.3 

0 

0 

20.1 

1.9 

2.4 

0.7 

1.8 

0.3 

- 

X = Mean. SE = Standard error of the mean. 

SD = Sham donation. BD = Blood donation. 

A = Tension-anxiety. B = Depression-dejection. 

C = Anger-hostility. D = Vigor. 

E = Fatigue. F = Confusion-bewilderment. * = <0.05 

All symbols have been defined previously in Table I or the text. 

P17 
TABLE 111. 

CHb and Hct Data 

Percent of SD Value Percent of BD Value 

SD + Id + 3d BD + Id + 3d + 7d 

- I 

CHb X 

g/dL SE 0.3 0.5 1.4 0.3 1.2 1.3 1.0 

13.8 100.6 99.7 13.8 90.9* 89.8* 91.8* 

- 

- Hc t X 41.7 100.5 100.1 41.8 91.7* 89.l* 91.4* 

Percent SE 0.7 0.6 1.5 0.8 0.7 0.9 1.0 

CHb = Hemoglobin concentration (g/dL of whole blood). 

Hct = Hematocrit (mL of erythrocytes/dL of whole blood). 

The means and standard errors for CHb and Hct at BD + 7 d are based on a 

paired sample n of 8. 

All other symbols have been defined previously in the Tables or the text. 

18 
TABLE IV. 

Control Measurements 

Ground Level (394 m MSL) 

torr 

SBP DBP PP AP 

60.4 

3.7 

57. l 

2.3 

62.2 

3.1 

59.3 

3.1 

50.7 I 77.3 

2.5 3.6 

47.3 72.8 

1.8 2.6 

46.6 77.7 

2.9 3.0 

SBP = Systolic blood pressure. PP = Pulse pressure. 

DBP = Diastolic blood pressure. HR = Heart rate. 

AP = Mean arterial pressure = DBP f 1/3 PP. 

torr = mm of mercury pressure. bpm = Beats per min. 

All other sy&ols have heen defined previously in the Tables 

or the text. 

19 
TABLE V. 

SBP (torr) 

(During P&M test at altitude) 

6,000 ft 

BD + Id 

L 

SD f 3d 

I 

SE I 

BD + 3d x 

- 

106.9 

3.8 

109.6 

3.5 

110.0 

DBP 

8,000 :ft 10,000 ft 

113.1 110.7 

3.8 3.1 

107.3* 

113.2 114.4 

3.4 3.2 

107.1* 

3.5 3.6 

110.2* 111. o* 

3.2 3.5 

(torr) 

(During P&M test at altitude) 

6,000 ft 8,000 ft 10,000 ft 

r - 

X 59.6 61.7 64.5 

SD + Id 

SE 2.7 3.6 4.0 

- 

BD + Id 

X 58. 6 57.1 59.9 

SE 2.1 2.5 3.2 

- 

X 60.7 61.7 64.2 

SD + 3d 

SE 

SE 3.9 3.6 3. a 

X 59.2 60.3 59.1 

3.2 3.8 4.2 

- 

BD + 3d 

; 

All symbols have been defined previously in the Tables 

or the text. 

20 
TABLE VI. 

PP (torr) 

(During P&M test at altitude) 

SD + Id x 

SE 

- 

x 

BD + Id 

SE 

- 

X 

SD + 3d 

SE 

X 

BD + 3d 

SE 

6,000 ft 8,000 ft 10,000 ft 

49.4 51.4 

2.2 2.9 2.8 

51.4 51.3 52.3 

3.4 3.4 3.4 

48.9 51.5 50.2 

2.7 2.1 2.7 

47.9 50.2 47.2 

3.7 3.6 2.7 

46.2 

Ap (torr) 

(During P&M test at altitude) 

6,000 ft 8,000 Et 10,000 ft 

X 

SD + Id 

SE 

- 

X 

SE 

BD + Id 

- 

SD + 3d 

X 

SE 

- 

X 

SE 

3D + 3d 

76.0 

2.8 

78.8 79.8 

74.7 73.8* 75.6* 

3.3 3.5 

2.5 2.7 2.9 

77.0 78.9 81.0 

2.9 

75.7 76.0 

3.4 3.6 

3.7 3.1 3.4 

76.1 

~11 symbols have been defined previously Sn the Tables 

or the text. 

21 
TABLE VII. 

HR (bpm) 

(During P&M test at altitude) 

6,000 ft 8,000 ft 10,000 ft 

- 

X 80.2 

SE 2.9 3.6 2.9 

79.9 79.9 BD + 3d 

L 

QE (L/min BPS) 

(During P&M test at altitude) 

6,000 ft 8,000 ft 10,000 ft 

> 

x 11 8.65 1 8.74 1 8.55 

SD + Id 

1 SE 0.48 0.49 1 0.49 

- I 1 

BD + Id X 

SE 0.38 0.40 0.48 

8.35 8.11* 8.48 

- r 

X 

SE 0.47 0.43 0.43 

X 8.15 8.11 8.12 

SE 0.47 0.56 0.53 

8.42 8.67 8.22 

SD + 3d 

- 

BD + 3d 

r 

QE = Pulmonary ventilation in L/min at body temperature 

All other symbols have been defined previously in the 

Tables or in the text. 

and pressure, saturated. 

22 
TABLE VPII. 

Hb02 (Percent Saturation) 

(During P&M test at altitude) 

6,000 ft 8,000 ft 10,000 ft 

Gag2 (mL/dL) 

(During P&M test at altitude) 

6,000 ft 8,000 ft 10,000 ft 

Hb02 = Oxyhemoglobin saturation in percent. 

Cw2 = Arterial oxygen content in mL of oxygen per 

All other symbols have been defined previously in the 

Tables or the text. 

dL of whole blood. 

23 
TABLE IX. 

P&M Data 

Arithmetic Error Score 

6,000 ft 8,000 ft 

111.7 104.2 

SD + Id 

- 

BD + Id X 11 159.0 I 193.3 

SE 52.1 53.1 

91.1 

SE 24.3 9.2 

X 125.3 126.9 

SE 36.5 24.1 

- 

X 107.2 

SD f 3d 

- 

BD + 3d 

10,000 ft 

~ ~- 

103.4 

18.7 

192.9 

74.7 

50.7 

14.8 

102.5 

33.7 

Eyehand Coordination Error Score 

6,000 ft 8,000 ft 10,000 ft 

- 

X 51.9 

SE 12.9 6.1 8.7 

33.9 45.9 

SD + Id 

X 68.4 49.6 81.2 

19.9 11.4 

X 

27.5 

X 68.4* 60.0 45.1 

SE 10.1 15.8 19.9 

29.8 45.0 33.5 

SE 22.3 23.4 16.9 

BD + ldSE 

- 

SD + 3d 

- 

BD + 3d 

24 
TABLE X. 

Orthostatic Testing 

SBP (torr) 

Seated Quiet Standing 

Control First min Fourth min 

II 1 I 

116.9 118.7 

SE 1 4.0 I 4.1 

SD + 3d 

- 

X 

SE 3.6 3.1 2.9 

106.9 114.9 115.2 

BD + 3d 

DBP (torr) 

Seated Quiet Standing 

Control First min Fourth min 

- 

- 

X 

X 58.5 64.7 69.7 

SE 2.1 3.6 3.3 

62.5 69.1 71.4 

SE 3.1 4.5 4.9 

X 

SE 

62.1 71.1 74.6 

2.4 3.0 2.9 

SD + Id 

- 

BD 4- Id 

- 

SD + 3d 

- 

58.6 

SE 

x /I 2.9 I 3.4 

BD + 3d 

All symbols have been defined previously in the Tables 

or the text, 
TABLE XI. 

Orthostatic Testing 

PP (torr) 

Seated Quiet Standing 

Control First min Fourth min 

AP (torr) 

Seated Quiet Standing 

Control First rnin Fourth min 

All symbols have been defined previously in the Tables 

or the text. 

26 
TABLE XI1 . Orthostatic Testing 

HR (bPd 

Seated Quiet Standing 

Control First min Fourth min 

All symbols have been defined previously in the Tables 

or the text. 

27 
'SABLE XIII. 

Pedal Ergometry Data 

At Max. Iso-HR At Max. Iso-Load 

Total Work(W x min) fE(L/minBTPS) HNbPd 

Max. Iso-HR = The same maximum heart rate at which total work 

(W x min) values are compared 

Max. Iso-Load = The same maximum total work value at which 

All other symbols E have been defined previously in the Tables or the 

text. 

V and HR values are compared 

28 
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