Influence of lowered muscle temperature upon postexercise hemodynamics

Our aim was to test the hypothesis that independently lowering muscle tissue temperature would attenuate postexercise increases in leg vascular conductance and decreases in arterial blood pressure. Eleven participants (4 females; age, 27 ± 6 yr; height, 176 ± 10 cm; weight, 72.8 ± 11.3 kg; and V̇o_2max 39.34 ± 7.69 mLO₂·kg·min) completed three trials wherein they donned a water-perfused suit and exercised for 60-min at 60% V̇o_2max followed by 60-min supine recovery. Different water-circulation protocols were used to either maintain normal skin and muscle temperatures throughout recovery (normothermic), lower skin and muscle temperatures during recovery (cold), or lower muscle temperature but rewarm the skin temperature back to normal during recovery (rewarming). Internal (Tcore), skin (Tskin), and muscle temperatures (Tmuscle), mean arterial pressure, leg and cutaneous vascular conductance's were measured. Tcore was not different between trials (P > 0.05). Throughout the final 15 min of recovery, Tmuscle was lower (60 min: 35.94 ± 0.83°C vs. 36.74 ± 0.27°C, P < 0.05), but Tskin was not different (60 min: 33.8 ± 0.5°C vs. 33.9 ± 0.5°C, P > 0.05) in the rewarming relative to the normothermic trial. However, mean arterial pressure, leg vascular conductance, and cutaneous vascular conductance were not different between normothermic and rewarming trials (all P > 0.05). The findings suggest that independently lowering muscle tissue temperature after exercise does not alter whole leg vascular conductance or decreases in arterial blood pressure.NEW & NOTEWORTHY Our aim was to independently examine the influence of lowered muscle temperature upon leg vascular conductance and arterial blood pressure following exercise in cold or thermoneutral environments when skin and core temperatures and cutaneous vascular conductance were similar. These findings indicate that independent reductions in muscle temperature following exercise do not alter whole leg vascular conductance or postexercise arterial blood pressure when skin temperature and cutaneous vascular conductance are normal.