Postexercise hypotension causes a prolonged perturbation in esophageal and active muscle temperature recovery

We examined the effect of two levels of exercise-induced hypotension on esophageal (T_es) and active and nonactive muscle temperatures during and following exercise. Seven males performed an incremental isotonic test on a Kin-Com isokinetic apparatus to determine their peak oxygen consumption during bilateral knee extensions (V̇O_2sp). This was followed on separate days by 15-min of isolated bilateral knee extensions at moderate (60% V̇O_2sp) (MEI) and high (80% V̇O_2sp) (HEI) exercise intensities, followed by 90 min of recovery. Muscle temperature was measured with an intramuscular probe inserted in the left vastus medialis (T _vm) and triceps brachii (T_tb) muscles under ultrasound guidance. The deepest sensor (tip) was located ̃10 mm from the femur and deep femoral artery and from the superior ulnar collateral artery and humerus for the T_vm and T_tb, respectively. Additional sensors were located 15 and 30 mm from the tip with an additional sensor located at 45 mm for the T_vm measurements only. Following exercise, mean arterial pressure (MAP) remained significantly below preexercise rest for the initial 60 min of recovery after MEI and for the duration of the postexercise recovery period after HEI (P ≤ 0.05). After HEI, significantly greater elevations from preexercise rest were recorded for T_es and all muscle temperatures paralleled a greater decrease in MAP compared with MEI (all P ≤ 0.05). By the end of 90-min postexercise recovery, MAP, T_es, and all muscle temperatures remained significantly greater after HEI than MEI. Furthermore, a significantly shallower muscle temperature profile across T_vm, relative to preexercise rest, was observed at the end of exercise for both HEI and MEI (P ≤ 0.05), and for 30 min of recovery for MEI and throughout 90 min of recovery for HEI. No significant differences in muscle temperature profile were observed for T_tb. Thus we conclude that the increase in the postexercise hypotensive response, induced by exercise of increasing intensity, was paralleled by an increase in the magnitude and recovery time of the postexercise esophageal and active muscle temperatures.