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The thermoregulatory response to aerobic exercise has been extensively studied. By comparison, little attention has focused on the temperature changes observed during exercise of an anaerobic nature. This study was therefore designed to investigate whether thermoregulatory responses are different during and in recovery from intermittent and steady state exercise of the same cumulative workload. Eight males aged 21.5 ± 1.6 years acted as subjects for the study which had been approved by the local Human Ethics Committee. Subjects completed two experimental exercise sessions on an electrically braked cycle ergometer in a laboratory maintained at 21 ± 0.5°C. One exercise test required subjects to complete 30 min of continuous cycling at 60% VO2max, whilst the second was of an intermittent nature with subjects exercising at 90% VO2max for 20 repeated 1 min bouts separated by 2 min of recovery. This procedure allowed for the same total work to be performed in both protocols. The order of tests was randomised and preceeded by 15 min of supine rest and followed by 30 min of supine recovery. Core temperature (Tc) (10cm beyond the external anal sphincter), mean skin temperature (Tsk) and heart rate (HR) were measured before, during and in recovery from each protocol. Sweat production rate (SPR) was estimated from nude body mass measurement before and after exercise, and post-exercise blood lactate (La) was measured in an arterialised capillary sample. Tc, Tsk and SPR were significantly greater during exercise of an anaerobic/intermittent nature (P < 0.025). Tc and La were significantly elevated (P < 0.05) following anaerobic exercise, with Tc displaying a sustained end-recovery elevation of 0.54 ± 0.21. These results suggest the following; 1) that intermittent anaerobic exercise results in greater thermal stress than continuos exercise; and 2) that individuals participating in this form of exercise may be at greater risk of heat illness, particularly if performed in hotter climates.

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