Influence of Lowered Muscle Temperatures upon Post Exercise Hemodynamics

Our aim was to test the hypothesis that independently lowering muscle tissue temperature would attenuate post exercise increases in leg vascular conductance and decreases in arterial blood pressure. Eleven participants (4 females; age, 27 ± 6 years; height, 176 ± 10 cm; weight, 72.8 ± 11.3 kg; and VO 2max 39.34 ± 7.69 mlO 2 .kg.min) completed three trials wherein they donned a water-perfused suit and exercised for 60-minutes at 60% VO 2max followed by 60-minutes supine recovery. Different water-circulation protocols were employed to either maintain normal skin and muscle temperatures throughout recovery (Normothermic), lower skin and muscle temperatures during recovery (Cold) or lower muscle temperatures 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 minutes of recovery, Tmuscle was lower (60 minutes: 35.94 ± 0.83°C vs. 36.74 ± 0.27°C, P < 0.05), but Tskin was not different (60 minutes: 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.