The interaction between short-term exercise training and a diuretic-induced hypovolemic stimulus.
Nine healthy untrained males [mean (SEM) age, 20.2 (1) years; peak oxygen uptake (VO2max, 48.2 (2) ml.kg-1.min-1] took part in a study to examine whether short-term exercise training (cycle exercise 2 h.day-1 for 3 days at 60% VO2max), which normally results in an expansion of plasma volume (PV), can counteract a diuretic-induced hypovolemic stimulus (100 mg triamterene + 50 mg hydrochlorothiazide.day-1 for 5 days concurrent with exercise training) and restore PV to control levels. Resting and exercise responses (90 min, 60% VO2max) in the diuretic plus exercise training condition (D+E) were compared to a control (C) and a diuretic (D) condition in which no exercise was performed. Following the short-term training, PV was still decreased (P < 0.05) below C by -8.3 (3)% in D+E and was similar (P > 0.05) to the reduction in D [-12.4 (2)%]. The reduced PV in response to the diuretic was associated with similar (P > 0.05) elevations in resting aldosterone (ALDO) and norepinephrine (NOREPI) levels (ng.100 ml-1) in D [101 (12), 61 (4)] and D+E [85 (16), 60 (10)] above (P < 0.05) C [22 (5), 37 (4)]. During exercise, ALDO levels were increased (P < 0.05) by 66 (5) and 70 (10) ng.100 ml-1 in D and D+E, respectively, and the increase was greater (P < 0.05) than C [44 (8) ng.100 ml-1]. The rise in NOREPI during exercise was lower (P < 0.05) in D+E [164 (44) ng.100 ml-1] than in D [244 (24) ng.100 ml-1] with levels similar to C [176 (25) ng.100 ml-1]. Thus, the ALDO response to the diuretic was heightened at rest and during exercise but was not additionally affected by the short-term training session. Results suggest that 3 days of exercise training are unable to counteract the hypovolemic effects of a diuretic and restore PV to control levels despite chronic elevations in NOREPI and ALDO.
Zappe
D H
DH
Department of Kinesiology, University of Waterloo, Ontario, Canada.
Helyar
R G
RG
Green
H J
HJ
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001798:Blood Proteins / Q000378:metabolism; D001810:Blood Volume / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D004232:Diuretics / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D006728:Hormones / Q000097:blood; D006801:Humans; D006852:Hydrochlorothiazide / Q000494:pharmacology; D007677:Kidney Function Tests; D008297:Male; D009994:Osmolar Concentration; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010809:Physical Fitness; D014223:Triamterene / Q000494:pharmacology
D001798:Blood Proteins; D004232:Diuretics; D006728:Hormones; D006852:Hydrochlorothiazide; D014223:Triamterene