UC Research Institute for Sport and Exercise
Building 29
11 Kirinari Street
Bruce, 2617
Heat training
About
UCRISE is home to a purpose built environmental chamber that can generate temperatures of up to 50°C and relative humidity up to 90%. The chamber is used for athlete training and heat training research by UCRISE, the Australian Institute of Sport, and the ACT Academy of Sport. The chamber has also been used by members of the ACT Brumbies and Canberra Raiders for competition preparation and fitness maintenance during injury rehabilitation.
Heat exposure and heat acclimation have been used by athletes to prepare for competition in warm locations, such as the Hawaiian Ironman and summer Olympics, for many years. When exercising or competing in hot conditions an additional thermal strain is placed on the body which exacerbates the physiological response to exercise and subsequently hinders performance. By training in hot conditions, the body becomes heat acclimated, mitigating the negative effects of heat on exercise performance. Whilst the primary purpose of heat acclimation is to optimise performance in the heat and reduce the risk of heat illness, recent evidence suggests that heat acclimation may also improve performance during exercise in cool conditions. Many of the physiological adaptations promoted by heat training, such as body temperature regulation and an increase in VO2max in the heat, may be transferred to cooler conditions, leading to better performance in those conditions.
As the only facility of its kind in the ACT and Southern NSW, the UCRISE environmental chamber is the perfect location for those looking to complement their training with heat exposure or acclimate for an upcoming competition in a hot environment.
Group and private bookings for up to six people at a time are available by request. If you have any questions or would like to make a group booking please contact us.
At UCRISE, we use a system constructed by QRA International, a Singapore-based company that specialises in construction of athlete training facilities. To simulate hot and humid environments, a large heating system pumps hot dry air into the environmental chamber while a humidifier adds moist air to increase the relative humidity. As such, a range of environments (temperature and humidity) can be simulated.
Heat training is used by sport scientists, coaches and athletes for a number of reasons:
- to evoke additional physiological adaptation,
- to increase or maintain physiological/metabolic training load while maintaining or decreasing mechanical load,
- to pre-acclimate to hot,
- humid conditions before competing in hot/humid locations and/or to maintain fitness when injured or unable to complete normal/prescribed training.
During heat sessions at UCRISE you will train at a temperature of 30-35°C and a relative humidity of 40-60%. This range of conditions evokes beneficial adaptations and increases load during training sessions. Given that exposure to conditions above this range greatly increases the risk of heat illness, any training sessions at UCRISE with temperatures in excess of 35°C require clearance from the University of Canberra Human Research Ethics Committee.
Repeated exposure to hot and/or humid conditions promote physiological adaptations that lead to heat acclimation. The magnitude of adaptation is dependent on the intensity, frequency and duration of heat exposure and includes:
- Increased sweat rate
- Altered composition of sweat (less sodium/electrolyte)
- Earlier onset of sweating
- Increased plasma volume
- Increase blood volume
- Improve myocardial (cardiac muscle) efficiency
- Decrease carbohydrate metabolism
- Increase total body water
- Decrease core and skin temperature
- Increased skin blood flow
- Improved ventricular compliance
The physiological adaptations listed above help to improve the capacity for exercise in hot conditions and may improve exercise performance in temperate and cold conditions. The performance benefits include:
- Increased exercise intensity at lactate threshold
- Increased VO2max
- Improved time-trial performance
Optimal heat acclimation occurs when heat training sessions are performed daily for 10-14 days. However, research indicates heat acclimation and beneficial physiological adaptation can still occur if sessions are completed every three days (e.g. 2 sessions per week) for several weeks, and depending on the intended purpose of heat exposure, intermittent exposure may be more appropriate than daily exposures.
Physiological adaptation with heat acclimation can develop quite rapidly and most major changes occur within the first 4-7 days of heat training and exposure. However, to maximise physiological adaptation, most individuals, particularly those who are not highly trained, will require longer heat training periods (2-3 weeks). Once heat acclimation training ceases, any beneficial adaptations will be gradually lost, much like muscle mass and cardiovascular fitness would decline if you were to stop regular training. However, the rate of decay can be attenuated if you return to regular training in temperate or cool conditions.
Any possible adjustment to training sessions should be minimal and will depend on the intended purpose of the heat training and the overall volume and intensity of other training sessions.
If the overall aim of heat training is to induce further training load without increasing mechanical load or training duration, then no adjustments should be made to other training sessions and heat training should simply replace an equivalent session or sessions in temperate conditions. Alternatively, heat training sessions could be added to an existing training program to further increase training load.
If the overall aim of heat training is to evoke heat acclimation arising as a result of the increased thermal load, then heat training sessions should be the focal point of a 1-3 week training cycle. Heat training sessions should be completed on most days (4-7 sessions) in this period to maximise the acclimation potential. During initial heat training sessions, consider training at a steady state below lactate threshold (~65% of VO2max). To maintain a consistent thermal load, training intensity should increase to match the rate of acclimation. This can be achieved in two ways: by setting a target heart rate (or heart rate range), or by moderately increasing the exercise intensity (workload) after four, nine and 14 sessions (to match the general progression of heat acclimation).
Another important consideration when training in the heat is fluid intake. Given that sweating will be profuse, it is important to hydrate properly before, during and after training. Measuring body mass prior to and after training will identify rehydration needs, but also inform on sweat rate and fluid requirements during training in the heat.
Training in a hot and humid environment is very safe and the risk of an adverse reaction is minimal. To ensure client safety, all training sessions are monitored by UCRISE staff members who are completing post graduate studies in sport and exercise science.
