The effect of dynamic intermittent hypoxic conditioning on arterial oxygen saturation.
BACKGROUND
Increases in arterial oxygen saturation (SaO2) in response to intermittent hypoxic exposure (IHE) are well established. However, IHE protocols have historically involved static hypoxic environments. The effect of a dynamic hypoxic environment on SaO2 is not known.


OBJECTIVE
The purpose of this study was to examine the effect of dynamic IHE conditioning on SaO2 using the Cyclical Variable Altitude Conditioning Unit.


METHODS
Thirteen trained participants (9 males, age 30.1 +/- 9.2 years; 4 females, age 30.3 +/- 8.9 years) residing at or near sea level were exposed to a 7-week IHE conditioning protocol (mean total exposure time = 30.8 hours). Participants were exposed to a constantly varying series of hypobaric pressures simulating altitudes from sea level to 6858 m (22 500 feet) in progressive conditioning tiers, creating a dynamic hypoxic environment. SaO2 was evaluated using pulse oximetry (SpO2) 4 times: at 2740, 3360, and 4570 m, prior to and following the first 3 weeks of IHE, and at 4570, 5490, and 6400 m at the start and end of the final 4 weeks.


RESULTS
SpO2 improved 3.5%, 3.8%, and 4.1% at 2470, 3360, and 4570 m, respectively (P < .05), and 3.3%, 3.4%, and 5.9% at 4570, 5490, and 6400 m, respectively (P < .05). At 4570 m, SpO2 increased from 81.7% +/- 6.5% to 89.1% +/- 3.2% over the entire 7-week conditioning period.


CONCLUSIONS
The dynamic intermittent hypoxic conditioning protocol used in the present study resulted in an acclimation response, such that SpO2 was significantly increased at all altitudes tested, with shorter exposure times than generally reported.
Hetzler
Ronald K
RK
Department of Kinesiology and Rehabilitation Science, College of Education, University of Hawaii, Honolulu, HI 96822, USA.
Stickley
Christopher D
CD
Kimura
Iris F
IF
LaBotz
Michelle
M
Nichols
Andrew W
AW
Nakasone
Kenneth T
KT
Sargent
Ryan W
RW
Burgess
Lawrence P A
LP
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D000531:Altitude; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000379:methods; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology; D013997:Time Factors; D055815:Young Adult
D010100:Oxygen