Abstract
Aim. The purpose of this study was to determine the response of circulating markers of lipid and protein oxidation following an incremental test to exhaustion before and after 4 weeks of high-intensity interval training performed in the heat. Methods. To address this question, 16 physically active men (age = 23 ± 2 years; body mass = 73 ± 12 kg; height = 173 ± 6 cm; % body fat = 12.5 ± 6 %; body mass index = 24 ± 4 kg/m(2)) were allocated into 2 groups: control group (n = 8) performing high-intensity interval training at 22°C, 55% relative humidity and heat group (n = 8) training under 35°C, 55% relative humidity. Both groups performed high-intensity interval training 3 times per week for 4 consecutive weeks, accumulating a total of 12 training sessions. Before and after the completion of 4 weeks of high-intensity interval training, participants performed an incremental cycling test until exhaustion under temperate environment (22°C, 55% relative humidity) where blood samples were collected after the test for determination of exercise-induced changes in oxidative damage biomarkers (thiobarbituric acid reactive species and protein carbonyls). Results. When high-intensity interval training was performed under control conditions, there was an increase in protein carbonyls (p < 0.05) following the incremental test to exhaustion with no changes in thiobarbituric acid reactive species. Conversely, high-intensity interval training performed in high environmental temperature enhanced the incremental exercise-induced increases in thiobarbituric acid reactive species (p < 0.05) with no changes in protein carbonyls. Conclusion. In conclusion, 4 weeks of high-intensity interval training performed in the heat enhances exercise-induced lipid peroxidation, but prevents protein oxidation following a maximal incremental exercise in healthy active men.