EPicks: Does short‐term heat acclimation enhance whole‐body evaporative heat loss?

In this video, Naoto Fujii discusses his latest paper on the effects of short‐term heat acclimation on whole‐body heat exchange and local nitric oxide synthase‐ and cyclooxygenase‐ dependent heat loss responses in exercising older men.

Read more in Experimental Physiology
https://physoc.onlinelibrary.wiley.co...
Effects of short‐term heat acclimation on whole‐body heat exchange and local nitric oxide synthase‐ and cyclooxygenase‐dependent heat loss responses in exercising older men

Naoto Fujii Gregory W McGarr Sean R Notley Pierre Boulay Ronald J Sigal Tatsuro Amano Takeshi Nishiyasu Martin P Poirier Glen P Kenny

106(2), pp. 450-462

Transcript:

I am Naoto Fujii, Assistant Professor at University of Tsukuba, Japan.
I’ll be discussing our recent article published in Experimental Physiology. The data for this article was collected at the University of Ottawa, Canada.

Heat acclimation can improve the heat loss responses of cutaneous vasodilation and sweating in older adults. However, how this improvement is achieved is unknown.

To elucidate this, eight older men completed a calorimetry and microdialysis trial before and after 7-day exercise-heat acclimation.

For the calorimetry trials, whole-body evaporative and dry heat exchange were assessed using direct calorimetry during cycling at light, moderate and vigorous metabolic heat productions in dry-heat.

For the microdialysis trials, local cutaneous vascular conductance and sweat rate were assessed during exercise in the heat at four forearm skin sites treated with lactated Ringers serving as a control, nitric oxide synthase inhibitor, cyclooxygenase inhibitor, or combined inhibition of both enzymes.

Evaporative heat loss increased following acclimation, but dry heat gain did not differ following acclimation.

Heat acclimation did not modulate the effects of separate and combined inhibition of nitric oxide synthase and cyclooxygenase on cutaneous vascular conductance.

Similar results were also obtained for sweating responses as well.

Our results suggest that short-term exercise heat acclimation improves evaporative heat loss, but it does not modulate nitric oxide synthase or cyclooxygenase contributions to cutaneous vasodilation or sweating in older men during an exercise-heat stress.