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

Abstract

We examined the effect of two levels of exercise-induced hypotension on esophageal (Tes) 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 (VO2sp). This was followed on separate days by 15-min of isolated bilateral knee extensions at moderate (60% VO2sp) (MEI) and high (80% VO2sp) (HEI) exercise intensities, followed by 90 min of recovery. Muscle temperature was measured with an intramuscular probe inserted in the left vastus medialis (Tvm) and triceps brachii (Ttb) muscles under ultrasound guidance. The deepest sensor (tip) was located approximately 10 mm from the femur and deep femoral artery and from the superior ulnar collateral artery and humerus for the Tvm and Ttb, respectively. Additional sensors were located 15 and 30 mm from the tip with an additional sensor located at 45 mm for the Tvm 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< or =0.05). After HEI, significantly greater elevations from preexercise rest were recorded for Tes and all muscle temperatures paralleled a greater decrease in MAP compared with MEI (P< or =0.05). By the end of 90-min postexercise recovery, MAP, Tes, and all muscle temperatures remained significantly greater after HEI than MEI. Furthermore, a significantly shallower muscle temperature profile across Tvm, relative to preexercise rest, was observed at the end of exercise for both HEI and MEI (P< or=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 Ttb. 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.

A three-compartment thermometry model for the improved estimation of changes in body heat content

“…Indeed, regional muscle temperature at any point in time is the result of regional differences in metabolic rate, conductive heat loss to adjacent tissue, and deep and peripheral convective blood flow (9). Furthermore, the convective transfer of muscle heat load to cooler tissues in the body has been demonstrated to significantly prolong the elevation of core temperature and presumably body heat content after exercise, with hyperemic previously active musculature considered to have the most profound influence (23,25).…”

“…Skin temperature is strongly influenced by skin blood flow, which itself can be significantly modified independently of whole body thermal state. For example, varying levels of exercise intensity result in different skin-to-muscle perfusion ratios, with increasing blood flow shunted away from skin to working muscle groups with greater levels of exercise (23). Furthermore, factors such as hydration status (29), training status (30), level of acclimatization (10), and the administration of topically applied medications, such as corticosteroids and nicotinates (21), have been demonstrated to alter skin blood flow during exercise.…”

“…The catheter stylet was then withdrawn, and the temperature probe was inserted into the catheter shaft. The probe assembly, including the catheter shaft, was secured to the skin with sterile, waterproof dressing (23,25). The implant site for the vastus lateralis was approximately midway between, and lateral to, a line joining the anterior superior iliac spine and the superior aspect of the centre of the patella (23)(24)(25).…”

“…The probe assembly, including the catheter shaft, was secured to the skin with sterile, waterproof dressing (23,25). The implant site for the vastus lateralis was approximately midway between, and lateral to, a line joining the anterior superior iliac spine and the superior aspect of the centre of the patella (23)(24)(25). The triceps brachii muscle temperature probe was inserted approximately midway between, and lateral to, a line joining the greater Values given are means, standard deviation (in parentheses) and range (maximum-minimum).…”

“…tubercle of the humerus and the superior aspect of the olecranon of the ulna (23,25). The upper trapezius muscle temperature probe was inserted 3 cm superior to the center point between the acromion process and superior angle of the scapula.…”