European Journal of Applied Physiology | 2019
Independent or simultaneous lowering of core and skin temperature has no impact on self-paced intermittent running performance in hot conditions
Abstract
PurposeTo investigate the effects of lowering core (Tgi) and mean skin temperature (Tsk) concomitantly and independently on self-paced intermittent running in the heat.Methods10 males (30.5\u2009±\u20095.8 years, 73.2\u2009±\u200914.5\xa0kg, 176.9\u2009±\u20098.0\xa0cm, 56.2\u2009±\u20096.6\xa0ml/kg/min) completed four randomised 46-min self-paced intermittent protocols on a non-motorised treadmill in 34.4\u2009±\u20091.4\xa0°C, 36.3\u2009±\u20094.6% relative humidity. 30-min prior to exercise, participants were cooled via either ice slurry ingestion (INT); a cooling garment (EXT); mixed-cooling (ice slurry and cooling garment concurrently) (MIX); or no-cooling (CON).ResultsAt the end of pre-cooling and the start of exercise Tgi were lower during MIX (36.11\u2009±\u20091.3\xa0°C) compared to CON (37.6\u2009±\u20090.5\xa0°C) and EXT (36.9\u2009±\u20090.5\xa0°C, p\u2009<\u20090.05). Throughout pre-cooling Tsk and thermal sensation were lower in MIX compared to CON and INT, but not EXT (p\u2009<\u20090.05). The reductions in thermophysiological responses diminished within 10–20\xa0min of exercise. Despite lowering Tgi, Tsk, body temperature (Tb), and thermal sensation prior to exercise, the distances covered were similar (CON: 6.69\u2009±\u20091.08\xa0km, INT: 6.96\u2009±\u20090.81\xa0km, EXT: 6.76\u2009±\u20090.65\xa0km, MIX 6.87\u2009±\u20090.70\xa0km) (p\u2009>\u20090.05). Peak sprint speeds were also similar between conditions (CON: 25.6\u2009±\u20094.48\xa0km/h, INT: 25.4\u2009±\u20093.6\xa0km/h, EXT: 26.0\u2009±\u20094.94\xa0km/h, MIX: 25.6\u2009±\u20093.58\xa0km/h) (p\u2009>\u20090.05). Blood lactate, heart rate and RPE were similar between conditions (p\u2009>\u20090.05).ConclusionLowering Tgi and Tsk prior to self-paced intermittent exercise did not improve sprint, or submaximal running performance.