The Effect of Submaximal Exercise on Recovery Hemodynamics and Thermoregulation in Men and Women

Abstract

Five women and 5 men were studied to examine the effects of submaximal exercise on thermoregulatory and hemodynamic variables during recovery in two environments: (a) control (C), 22 degrees C, 33% rh; and (b) hot humid (H), 32 degrees C. The participants exercised on a cycle ergometer at 60% of peak oxygen consumption for 35 min prior to 90 min of seated recovery. Sessions were identical, except for environment. Variables evaluated (p < .05) were: core temperature (TR), mean skin temperature (Ts), sweat rate (SR), heart rate (HR), stroke index (SI), cardiac index (CI), forearm blood flow (FBF), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Men and women exhibited similar patterns of TR, Ts, and SR in both environments. Ts and SR (collapsed means for gender) were higher in the H than in the C. DBP was higher in men than in women throughout recovery in both environments. With combined means for gender, HR was higher in the H than in the C. CI, SI, FBF, and SBP were similar in both environments and returned to baseline within 15 min into recovery. These data suggest that heat dissipation during extended recovery was accomplished with similar contributions of cutaneous vasodilation and sweating in M and F. Furthermore, the moderate exercise level did not influence hemodynamics beyond 15 min of recovery in either environment.

Evidence of a greater onset threshold for sweating in females following intense exercise

“…It is known, that while the temporal pattern of postexercise hypotension following a single bout of exercise is similar in both sexes, the more pronounced depression in postexercise blood pressure in females relative to males (Carter et al 2001;Fisher et al 1999;Kenny et al 2006b) is paralleled by a concomitant elevation in core and muscle tissue temperature in females (Kenny and Jay 2007); and an increased postexercise core temperature onset threshold for cutaneous vasodilation relative to males (Kenny et al 2006b). The sweating onset thresholds for males and females, however, have not yet been compared.…”

Thermoregulatory effects of 3,4-methylenedioxymethamphetamine (MDMA) in humans

“…Confounding the direct effect of MDMA on body temperature is the fact that MDMA is most often consumed at dances. Exercise alone increases core body temperature (Gleeson 1998;Fisher et al 1999), so it is possible that MDMA plus exercise (vigorous dancing) will have a greater effect than either exercise alone or MDMA alone. The mechanism by which MDMA causes increases in body temperature has not been elucidated in humans, but it is likely that elevated body temperatures can lead to even fatal outcomes (Green et al 2004).…”

The influence of hydration status on heart rate variability after exercise heat stress

“…Inactive recovery from exercise is associated with the cessation of the primary feedforward exercise stimulus from the brain (central command), which is responsible for the initial rapid deceleration in HR (Carter et al, 1999). Other factors influencing autonomic control of cardiac deceleration may include changes in afferent stimuli from muscle metabo-and mechanoreceptors (Wilson et al, 2004), baroreceptors, and thermoreceptors (Fisher et al, 1999). Nevertheless, the robust return of parasympathetic activity is considered to be the main mechanism underlying cardio-deceleration after exercise (Carter et al, 1999;Nishime et al, 2000).…”