Baroreceptor modulation of active cutaneous vasodilation during dynamic exercise in humans

Area of Science:

• Exercise Physiology
• Cardiovascular Regulation
• Thermoregulation

Background:

• Cutaneous vasodilation is crucial for heat dissipation during exercise.
• The baroreflex, which regulates blood pressure, may influence skin blood flow during physical activity.

Purpose of the Study:

• To test the hypothesis that baroreceptor unloading during dynamic exercise limits cutaneous vasodilation by withdrawing active vasodilator activity.
• To investigate the role of the baroreflex in modulating active cutaneous vasodilation during exercise.

Main Methods:

• Seven healthy subjects performed dynamic exercise with and without lower body negative pressure (LBNP) to induce baroreceptor unloading.
• Forearm skin blood flow and arterial blood pressure were measured to calculate cutaneous vascular conductance (CVC).
• Laser-Doppler velocimetry and noninvasive blood pressure monitoring were utilized.

Main Results:

• Baroreceptor unloading during exercise delayed the onset of cutaneous vasodilation.
• Lower body negative pressure significantly limited peak CVC at vasodilator-only skin sites.
• The increase in core body temperature required to elicit vasodilation was higher during exercise with LBNP.

Conclusions:

• Baroreceptor unloading during dynamic exercise modulates active cutaneous vasodilation.
• Withdrawal of active vasodilator activity contributes to the reduced skin blood flow observed during baroreceptor unloading in exercise.
• These findings highlight the interplay between the baroreflex and thermoregulatory control of skin circulation during exercise.