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1995 Publications

Hormonal Responses to Exercise at the Anaerobic and Respiratory Compensation Thresholdsby Nina S. Stachenfeld, Ph.D., Gilbert W. Gleim, Ph.D., Neil L. Coplan, M.D., and James A. Nicholas, M.D.Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, 130E. 77 Street, New York, NY 10021 - last modified 2013-02-09 00:00
Med Exerc Nutr Health 1995;4:349-354


The sympatho-adrenal and plasma renin activity (PRA) responses, which are involved in the control of blood pressure and metabolism during exercise, are related to the lactate threshold (LT) during incremental exercise. However, the sympathetic nervous system (SNS) and PRA responses to exercise at the noninvasively derived anaerobic (AT) and respiratory compensation thresholds (RCT) have not been addressed. The purpose of this study was to compare SNS and PRA responses to prolonged exercise at AT and RCT. Ten women (mean +/- SEM, VO2peak = 50.5 +/- 3 mL/kg/min) exercised on a cycle ergometer for 20 minutes at AT or RCT on separate days. NE, EPI, and PRA were determined at rest, end exercise, 2, 5, and 10 minutes of recovery by sampling from a forearm vein. AT and RCT occurred at 57 +/- 3% and 76 +/- 3% peak oxygen consumption, respectively. ANOVA revealed significantly greater increases in NE and PRA during exercise at RCT, but no difference in EPI response between the two thresholds. These data indicate that steady-state exercise at RCT was associated with a greater sympathetic response compared with AT.