Cyclooxygenase-1 and -2 modulate sweating but not cutaneous vasodilation during exercise in the heat in young men

Abstract

We recently reported that the nonselective cyclooxygenase (COX) inhibitor ketorolac attenuated sweating but not cutaneous vasodilation during moderate‐intensity exercise in the heat. However, the specific contributions of COX‐1 and COX‐2 to the sweating response remained to be determined. We tested the hypothesis that COX‐1 but not COX‐2 contributes to sweating with no role for either COX isoform in cutaneous vasodilation during moderate‐intensity exercise in the heat. In thirteen young males (22 ± 2 years), sweat rate and cutaneous vascular conductance were measured at three forearm skin sites that were continuously treated with (1) lactated Ringer's solution (Control), (2) 150 μmmol·L−1 celecoxib, a selective COX‐2 inhibitor, or (3) 10 mmol L−1 ketorolac, a nonselective COX inhibitor. Participants first rested in a non heat stress condition (≥85 min, 25°C) followed by a further 70‐min rest period in the heat (35°C). They then performed 50 min of moderate‐intensity cycling (~55% peak oxygen uptake) followed by a 30‐min recovery period. At the end of exercise, sweat rate was lower at the 150 μmol·L−1 celecoxib (1.51 ± 0.25 mg·min−1·cm−2) and 10 mmol·L−1 ketorolac (1.30 ± 0.30 mg·min−1·cm−2) treated skin sites relative to the Control site (1.89 ± 0.27 mg·min−1·cm−2) (both P ≤ 0.05). Additionally, sweat rate at the ketorolac site was attenuated relative to the celecoxib site (P ≤ 0.05). Neither celecoxib nor ketorolac influenced cutaneous vascular conductance throughout the experiment (both P > 0.05). We showed that both COX‐1 and COX‐2 contribute to sweating but not cutaneous vasodilation during moderate‐intensity exercise in the heat in young men.

Heat shock protein 90 modulates cutaneous vasodilation during an exercise‐heat stress, but not during passive whole‐body heating in young women

“…Finally, the disparate findings regarding the role of HSP90 in modulating cutaneous vasodilation in this study coincide with other work showing differences in the modulation of this heat loss response between the two heating modalities (Fujii et al, 2018;Holowatz et al, 2006;Kellogg et al, 2009;McCord et al, 2006;McNamara et al, 2014;Meade et al, 2019). This highlights the need to further explore the end-organ factors that modulate cutaneous vasodilation during exercise-heat stress in healthy young adults, since this response remains poorly understood relative to that of passive whole-body heating and it is becoming increasingly clear that one model cannot readily be used as a surrogate to inform the other.…”

“…However, whether the HSP90 contribution to cutaneous vasodilation during an exercise-heat stress is due to the increase in body core temperature per se or if it is also associated with exercise-induced increases in metabolic and hemodynamic strain, remains uncertain. This is important since the mechanisms regulating cutaneous vasodilation in response to body core temperature elevations during passive heating do not always coincide with those observed during an exercise-heat stress (Fujii et al, 2018;Holowatz, Thompson, & Kenney, 2006;Kellogg, Zhao, & Wu, 2009;McCord, Cracowski, & Minson, 2006;McNamara, Keen, Simmons, Alexander, & Wong, 2014;Meade et al, 2019).…”

The influence of environmental and core temperature on cyclooxygenase and PGE2 in healthy humans

“…a febrile state 33 , 34 ). However, local (forearm) COX2 inhibition (celecoxib) has attenuated sweat response during exercise under heat stress in healthy (free from pathology/febrile state) humans 53 . Further, COX2 mRNA has been present in many tissues free from pathology (e.g.…”

Non-steroidal anti-inflammatory drugs on core body temperature during exercise: A systematic review

“…NSAIDs may increase Tc by impairing sweat responses. 46 , 47 However, based on a lack of significant sweat rate or skin temperature responses during exercise between control and NSAIDs, 18 , 37 , 43 Tc differences likely occurred through other mechanisms. Bruning et al.…”