RESUMO
PURPOSE: To examine the effects of a single low-dose (500 mg) acetaminophen on body temperature and running performance in the heat (30 °C). METHODS: This is a randomized, cross-over pilot study performed in a climatic chamber at the Department of Sport Science of the University of Innsbruck. Seven male sport students (age, 25.9 ± 2.3 years; VO2max, 67.3 ± 7.1 mL/min/kg) participated in the study. Each participant performed two prolonged exercise tests at a constant intensity on a treadmill at a temperature of 30 °C at an individual intensity corresponding to 70 % VO2max. Two hours before exercising participants were randomly assigned to receive acetaminophen (500 mg) or placebo and performed the same test 2 weeks later with reverse pre-treatment. RESULTS: After 20 min of running in the heat core temperature increase was less under acetaminophen (P = 0.004) and heart rates were higher (P = 0.02) compared to placebo. At the end of exercise neither running time nor body temperature nor ratings of perceived exertion differed between groups. CONCLUSION: Although the increase in core temperature was slightly reduced by acetaminophen after 20 minutes of running in the heat running performance remained unaffected after pre-treatment with a single low-dose of acetaminophen.
