Comparison of a Novel Condensed Heat Acclimation Programme With a Traditional Longer-term Heat Acclimation Programme
Condition: Heat Stress
MeSH terms: Heat Stress Disorders
Study type: Interventional

Summary: 
      Repeated exposure to heat in a laboratory setting (acclimation) elicits a range of
      adaptations, which reduce heat illness risk and increase work capacity in the heat.
      Traditional approaches to heat acclimation require daily heat exposures of 1 to 2 hours over
      ~7 to 10 consecutive days. Heat acclimation approaches which reduce the number of days to
      achieve acclimation may have utility. The primary purpose of the proposed research is to
      determine whether it is possible to achieve a similar degree of heat acclimation to that seen
      with a traditional longer-term heat acclimation approach by increasing the frequency of heat
      exposure, utilising multiple daily heat exposures over a smaller number of days. Secondary
      aims of the research are to examine whether heat acclimation provides cross-adaptation to a
      hypoxic stressor and whether heat acclimation improves aerobic fitness.
    

Detailed description: 
      Individuals are often required to operate in adverse conditions and may be exposed to
      prolonged periods of high ambient heat and humidity. High environmental temperatures impair
      work capacity and increase heat-illness risk. Repeated exposure to heat in a laboratory
      setting (acclimation) elicits a range of adaptations, which reduce heat illness risk and
      increase work capacity in the heat. However, traditional approaches to heat acclimation are
      time consuming, typically requiring daily heat exposures of 1 to 2 hours over ~7 to 10
      consecutive days. This can be logistically difficult to implement and impractical,
      particularly in situations where an individual must be rapidly deployed. Therefore, heat
      acclimation approaches which reduce the number of days to achieve acclimation may have
      utility. In addition, recent research studies have suggested that adaptation to heat may
      improve tolerance to hypoxia (cross-adaptation) and improve aerobic fitness; these effects
      may also be beneficial in a military context. Therefore, the primary purpose of the proposed
      research is to determine whether it is possible to achieve a similar degree of heat
      acclimation to that seen with a traditional longer-term heat acclimation approach by
      increasing the frequency of heat exposure, utilising multiple daily heat exposures over a
      smaller number of days. Secondary aims of the research are to examine whether heat
      acclimation provides cross-adaptation to a hypoxic stressor and whether heat acclimation
      improves aerobic fitness. Heat acclimation will be evaluated using a range of whole-body
      (cardiovascular, thermoregulatory, psychophysiological) and biochemical markers.
    

Intervention name(s): Heat acclimation
Intervention type(s): Other
Intervention description(s): Repeated heat exposures with light exercise sufficient to elevate deep body temperature to ~ 38.5C
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Parallel groups design
Masking: None (Open Label)
Primary purpose: Prevention