Journal of Applied Physiology, Vol 38, Issue 6 996-1001, Copyright © 1975 by American Physiological Society
Exercise responses following ozone exposure
L. J. Folinsbee, F. Silverman and R. J. Shephard
We have tested the response of 28 subjects to a three-stage ergometer test,
with loads adjusted to 45, 60, and 75% of maximum aerobic power following
ozone exposure. The subjects were exposed to one of 0.37, 0.50, or 0.75 ppm
O3 for 2 h either at rest (R) or while exercising intermittently (IE) (15
min rest alternated with 15 min exercise at approximately 50 W. sufficient
to increase VE by a factor of 2.5). Also, all subjects completed a mock
exposure VE, respiratory frequency (fR), mixed expired PO2 and PCO2, and
electrocardiogram were monitored continuously during the exercise test.
Neither submaximal exercise oxygen consumption nor minute ventilation was
significantly altered following any level of ozone exposure. The major
response noted was an increase in respiratory frequency during exercise
following ozone exposure. The increase in fR was closely correlated with
the total dose of ozone (r = 0.98) and was accompanied by a decrease in
tidal volume (r = 0.91) so that minute volume was unchanged. It is
concluded that through its irritant properties, ozone modifies the normal
ventilatory response to exercise, and that this effect is dose dependent.
