Oxidative stress does not influence local sweat rate during high-intensity exercise

Area of Science:

• Exercise Physiology
• Human Physiology
• Thermoregulation

Background:

• Nitric oxide (NO) plays a role in regulating sweat production.
• Exercise-induced oxidative stress may impair NO-dependent sweating, particularly during high-intensity exercise.
• Previous research suggested a link between oxidative stress and reduced NO-dependent cutaneous vasodilation during intense exercise.

Purpose of the Study:

• To investigate whether oxidative stress attenuates the contribution of nitric oxide (NO) to sweating during high-intensity exercise.
• To determine if antioxidant administration influences NO-dependent sweating during moderate and high-intensity exercise.
• To elucidate the mechanistic insights into how exercise-induced oxidative stress impacts sudomotor activity.

Main Methods:

• 11 young men performed cycling exercise in heat (35°C) at moderate (∼51% peak oxygen uptake) and high (∼72% peak oxygen uptake) intensities.
• Local sweat rate was measured at forearm sites perfused with lactated Ringer solution, ascorbate (antioxidant), N-nitro-l-arginine methyl ester (NO synthase inhibitor), or ascorbate + l-NAME.
• Comparisons were made between treatment sites and control during different exercise intensities.

Main Results:

• During moderate exercise, sweat rate was attenuated by l-NAME, indicating NO dependence.
• During high-intensity exercise, no differences in sweat rate were observed between control, ascorbate, l-NAME, or ascorbate + l-NAME treated sites.
• Ascorbate administration did not alter sweat rates at either moderate or high-intensity exercise, suggesting oxidative stress does not impair NO-dependent sweating.

Conclusions:

• Diminished NO-dependent sweating during intense exercise occurs independently of oxidative stress.
• The findings challenge previous assumptions about the role of oxidative stress in modulating NO-dependent sweating during high-intensity exercise.
• Further research is needed to identify the specific mechanisms responsible for reduced NO-dependent sweating during strenuous physical activity.