Oral ingestion of acetylsalicylic acid on skin blood flow and local sweat rate during heat stress

Abstract

Acetylsalicylic acid (ASA) is an over-the-counter drug used for pain relief and fever suppression. As a nonselective cyclooxygenase-inhibitor, ASA has systemic effects that may influence hypothalamic-mediated temperature regulation. Three studies were performed to evaluate the effects of oral ASA ingestion on skin blood flow (SkBF) and sweating during passive and exercise-induced heat stress. Passive whole-body heating was achieved with the use of a water-perfused suit to raise body temperature. In a separate study, submaximal cycling was performed. Study one examined SkBF and local sweating responses during passive heating following acute ASA ingestion of different concentrations (325-mg and 81-mg). Study two examined the influence of four consecutive days of low-dose (81-mg) ASA ingestion on SkBF and local sweating responses during passive heating. Study three examined acute ASA administration of different concentrations (325-mg and 81-mg) on SkBF and local sweating during submaximal cycling at 50% heart rate reserve for 45 min and followed with 15 min of passive recovery (35 °C, 30-40% rH). Young, healthy male participants maintaining moderately active lifestyles volunteered for these studies. In a repeated measures, counter-balanced design, participants completed passive heating and submaximal cycling while SkBF and local sweat responses were continuously measured. As indicated by group mean data, results from study one suggested that acute ASA ingestion of a modest dose did not negatively influence thermoregulatory responses during whole-body passive heating. Results from study two suggested that low-dose ASA ingestion over four consecutive days did not alter thermoregulatory responses during whole-body passive heating. Results from study three suggest that acute ASA ingestion of a modest dose did not alter thermoregulatory responses during exercise or passive recovery in the heat. The collective results from these investigations support the assertion that ASA use does not negatively affect temperature regulation in a cohort of young healthy male participants under conditions similar to those described.