Journal of Applied Physiology, Vol 58, Issue 3 702-709, Copyright © 1985 by American Physiological Society
Effects of nifedipine on responses to exercise in normal subjects
B. Raffestin, A. Denjean, A. Legrand, C. Derrieux, J. Boillot, E. Comoy, H. Martre and A. Lockhart
The responses to sublingual nifedipine (20 mg) and placebo were compared in
normal subjects during two studies on cycle ergometer [progressive exercise
and constant work-load exercise at approximately 60% of maximal O2
consumption (VO2max)]. The use of nifedipine did not modify maximal power,
ventilation (VE), VO2, and heart rate (HR) at the end of the multistage
progressive exercise (30-W increments every 3 min). Over the 45 min of the
constant-load exercise and the ensuing 30-min recovery we observed with
nifedipine compared with placebo 1) no differences in VO2, VE, respiratory
exchange ratio, and systolic arterial blood pressure; 2) a higher HR (P
less than 0.001) and lower diastolic arterial blood pressure (P less than
0.01); 3) a greater and more prolonged rise in norepinephrine (P less than
0.01) and growth hormone (P less than 0.001); 4) no significant differences
in epinephrine and insulin and a lesser increase in glucagon during
recovery (P less than 0.01); and 5) a lesser fall in blood glucose (P less
than 0.01) and greater increase in acetoacetate (P less than 0.001),
beta-hydroxybutyrate (P less than 0.05), and blood lactate (P less than
0.001). Our data do not support the hypothesis that nifedipine reduces
hormonal secretions in vivo and are best explained by an enhanced secretion
of catecholamines compensating for the primary vasodilator effect of
nifedipine.
