Journal of Applied Physiology, Vol 46, Issue 5 984-991, Copyright © 1979 by American Physiological Society
Factors affecting the physical performance of the rat in hyperbaric environments
Y. C. Lin, L. H. Chen and D. G. Baker
Experiments were designed to partition the effect of inspired oxygen
tension (PIO2), gas density (rho), and ambient pressure (P) at rest and
during exercise in rats. At rest oxygen uptake (VO2) was reduced by 19.5%
(P less than 0.01) in 3 ATA air and by 32.1% (P less than 0.01) in 10 ATA
air from 1 ATA air control of 29.3 +/- 1.21 (SE) ml/min.kg; there was no
difference in VO2 between 1, 3, and 10 ATA He mixtures containing 20% O2.
During exercise, VO2 was depressed by 36.2% (P less than 0.01) in 3 ATA air
from 1 ATA air value of 55.3 +/- 3.23 ml/min.kg; VO2 was unaffected in 3
ATA He containing 20% O2 as compared to that of 46.5 +/- 2.43 ml/min.kg at
1 ATA He-O2 ambient. These VO2 values were compared to that obtained from
normoxic ambients for separation of effects of elevated PIO2, P, and rho on
VO2 at rest and during exercise. The effect of PIO2 was deduced by
comparing VO2 in normoxic and hyperoxic He and N2 at a given P and rho. The
density effect was obtained by comparing the VO2 in various densities at a
given P and PIO2. The P effect was obtained by comparing the VO2 in various
ambient pressures at a given rho and PIO2. Summation of the effects of P,
rho, and PIO2 sufficiently approximates the changes in VO2 at rest. The
same procedure underestimates the actually measured VO2 in all N2 ambients.
