The effect of water dousing on heat strain after exercise in trained cyclists

Materials and procedures: -Once enrolled into the study, participants will complete one familiarisation session and two experimental trials in an environmental chamber. Every session will involve only an individual participant completing the trials. -Each experimental session will take approximately a total of 3 to 4 hours and are undertaken 3-7 days apart. Data collected for this particular study is nested within larger project sessions. -A familiarisation session will occur 3-7 days prior to the first experimental session for the broader project and take approximately 3 hours. This will include participants completing an incremental test to exhaustion and a 30km time trial on the bike. The incremental test to exhaustion will be conducted in temperate conditions (22°C and 50% relative humidity) on bicycle ergometer with a metabolic cart to measure gas exchange. The test will consist of an initial four minute submaximal steady state exercise intensity, followed by the power output increasing by 25 W every minute until volitional exhaustion. - The two experimental sessions (intervention and control) require the participant to complete recovery cooling following both a 30km self-paced time trial and a 48 min fixed-intensity (65% of maximal oxygen consumption) cycle (i.e. two separate moments in the broader trial) in an environmental chamber set to 35°C and 20 % relative humidity. Recovery 1: Douse (intervention) vs no-douse (control) Immediately after the 30 km time-trial, a 30 min recovery period will begin where dousing or control (see details below) will occur at baseline and then every six minutes whilst undertaking passive rest (i.e. sitting on a chair; 5 total douses). Each douse will involve pouring 500 ml of water on the arms, upper legs, chest and back of the neck. The water will be approximately equal to air temperature (i.e. will not be cooled [~35°C]). A fan will be set to 10.2 km/h to mimic a light breeze and the participants will drink 150 ml of water every 6 min to simulate typical post-event water consumption. The consumed water will be 38°C. A further 30 min break where no experimental data will be collected will occur prior to beginning the 48 min fixed intensity cycling (at 65 % of maximal oxygen consumption). Recovery 2: Cold douse (intervention) vs cold drink (comparator) Following the 48 min fixed intensity exercise, a mixed-methods cooling design whereby both experimental trials will include a cold ice towel (~2.5 kg) being placed on the participant’s neck with the addition of either cold water dousing or the ingestion of cold water. The participants will consume 150 ml of 38°C water immediately after completing the fixed-intensity cycle, The ingested water will be 38°C to ensure that there is no cooling effect from the water consumed. The dousing protocol will involve spreading the water over the same body locations as recovery period 1, however the total volume will be 200ml each douse and the temperature of dousing water will be equivalent to the comparator cold drinking water trial (~10°C). A total of 1000ml will be doused over the 30 min across 5 total douses. The cold ice towel will be only placed around the neck for the first 6 min of the recovery. A fan will be set to maintain an air velocity of ~0.5-2.0 km/h. Who will deliver: A sport science graduate will lead data collection, and the remainder of the team are experienced researchers with 10-20 years of academic experience. Mode: In-person testing of individual participants Location: Environmental chamber at the Mile End campus of Adelaide University. Adherence: Research team member/s will supervise the participants at all times in the environmental chamber to ensure adherence to the study protocols.