Y. Bhambhani et al., EFFECTS OF 10-PPM HYDROGEN-SULFIDE INHALATION IN EXERCISING MEN AND WOMEN - CARDIOVASCULAR, METABOLIC, AND BIOCHEMICAL RESPONSES, Journal of occupational and environmental medicine, 39(2), 1997, pp. 122-129
This study examined the acute effects of 10-ppm hydrogen sulfide (H2S)
inhalation, a concentration equal to its occupational exposure limit,
on the cardiovascular, metabolic, and biochemical responses in health
y volunteers. Fifteen men and 13 women completed two 30-minute exercis
e sessions at 50% of their maximal oxygen uptake, during which they in
haled medical air or 10 ppm H2S in a blind manner. Arterial and finger
-prick blood samples were obtained before and during the final minute
of exercise. Muscle biopsies were withdrawn from the right vastus late
ralis immediately after exercise. Cardiorespiratory measurements were
monitored using an automated metabolic cart interfaced with an electro
cardiogram and blood pressure apparatus. A significant decrease in oxy
gen uptake (VO2), with a concomitant increase in blood lactate, was ob
served in men and women as a result of H2S exposure. No significant ch
anges were observed in arterial blood parameters and the cardiovascula
r responses under these conditions. Muscle lactate, as well as the act
ivities of lactate dehydrogenase, citrate synthase, and cytochrome oxi
dase, were not significantly altered by H2S exposure. However, there w
as a tendency for muscle lactate to increase and citrate synthase acti
vity to decrease in both genders in the presence of H2S. It appeared t
hat 10-ppm H2S inhalation reduced VO2 during exercise, most likely by
inhibiting the aerobic capacity of the exercising muscle. These findin
gs question the scientific validity of the current occupational exposu
re limit for H2S.