None listed
Conditions
Brief summary
The primary purpose of this study is to compare the adaptations induced between heat acclimation protocols where heat is generated endogenously by exercising wearing extra clothing, or exogenously in a hot environment, but with a matched overall stimulus. A secondary purpose is to evaluate the role of a possible training effect when the cardiovascular strain is matched in an exercising control condition. It is hypothesised that exercising wearing extra clothing will be as effective at inducing heat adaptations as the traditional approach of exercising in a hot environment.
Interventions
This study will be a within-subjects semi-randomised crossover comparing two 5-day isothermal heat acclimation training protocols: Exercising in a hot environment (40°C, 50% relative humidity) whilst wearing regular clothing (HEAT) or exercising in a temperate environment (20°C, 50% relative humidity) whilst wearing extra clothing (ExEC), All protocols will be separated by at least 5 weeks. Participants will undergo all conditions in a random order (except that CON will have to be after HEAT, no
This study will be a within-subjects semi-randomised crossover comparing two 5-day isothermal heat acclimation training protocols: Exercising in a hot environment (40°C, 50% relative humidity) whilst wearing regular clothing (HEAT) or exercising in a temperate environment (20°C, 50% relative humidity) whilst wearing extra clothing (ExEC), All protocols will be separated by at least 5 weeks. Participants will undergo all conditions in a random order (except that CON will have to be after HEAT, not necessarily directly). Regular clothing will be a breathable short sleeve top and shorts, socks and shoes. Extra clothing will be socks, thermal pants, shorts, trackpants, a long sleeve thermal top, t-shirt, a hoodie, a rain jacket, gloves and a buff. In each, participants will complete heat stress tests comprised of cycling for 45 min in a hot environment (40°C, 50% relative humidity) two days prior and post completing a 5 consecutive day heat acclimation protocol. The heat acclimation protocols involve cycling for 75 min each day in the respective environments. Sessions will be supervised directly by an experienced exercise physiologist. Participants will cycle initially at ~2.1 W/kg or 2.3 W/kg in HEAT or ExEC, respectively, until their core temperature has increased by 1.5°C, at which point the exercise intensity will be reduced and adjusted to maintain this temperature. These sessions will be conducted in the environmental chamber at the School of Physical Education, Sport and Exercise Sciences and supervised by the researchers.
Sponsors
University of Otago
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
• Being between 18 and 65 years old, • be of either sex or any gender, • not have any pre-existing conditions (e.g. injuries, any known cardiovascular/metabolic/respiratory disease) that increase risk during the tests, including meeting the requirements for the current Physical Activity Readiness Questionnaire (PAR-Q+) and Physical Fitness Questionnaire, • be unacclimatised to the heat, • be regularly physically active and fit to be able to sustain the relatively high workloads required for the given duration of the protocols.
Exclusion criteria
• any acute or chronic illnesses (e.g., diabetes, severe asthma, cardiovascular disease), • any injuries or consume medications that may impair ability to exercise in a hot environment (esp. diuretics or other cardiovascular-related medications), • any respiratory illness or recent (< 3 weeks) febrile illness, • having recently experienced moderate heat exposure (e.g. 30°C air temperature holiday in the last 5 weeks) or regular heat exposure (e.g. 2 hours per week sauna/spa bathing within the previous 5 weeks). If so, the individual would be asked to forgo use and or wait until they have been home for at least 5 weeks before participating.
Outcome results
None listed