Effects of Endurance Training on Vascular Responses to Mental Stress in Humans

Abstract

PURPOSE: We sought to determine if exercise training alters brachial and renal blood flow during mental stress. METHODS: Doppler ultrasound was used to measure brachial and renal blood flow during five minutes of mental stress induced by serial subtraction in seven healthy volunteers (24±1 years). Subjects were tested before and after eight weeks of endurance training. RESULTS: Endurance training elicited a 20% increase in VO2 peak. Mental stress elicited comparable increases in heart rate (~23 beats/min) and mean arterial blood pressure (~17 mmHg) both before and after endurance training. Mental stress elicited a biphasic response in brachial blood flow and vascular conductance both before and after exercise training. Brachial blood flow and vascular conductance increased during the first two minutes and returned to baseline by the fifth minute. These responses were not affected by training. Renal blood flow (55±6 and 44±4 cm/sec before and after training, respectively) and vascular conductance (0.58±0.07 and 0.51±0.04 cm/sec/ mmHg, respectively) were lower at rest after training. However, reductions in renal blood flow and vascular conductance during mental stress were not different before and after exercise training. CONCLUSION: Vascular hemodynamic responses to mental stress are not altered by short-term endurance training in humans. Supported by NIH HL077670 and DC006459, and NIH sponsored GCRC M01-RR-10732 and C06-RR-016499.