Abstract
Over the last few decades, females have significantly increased their participation in athletic competitions and occupations (e.g. military, firefighters) in hot and thermally challenging environments. Heat acclimation, which involves repeated passive or active heat exposures that lead to physiological adaptations, is a tool commonly used to optimize performance in the heat. However, the scientific community’s understanding of adaptations to heat acclimation are largely based on male data, complicating the generalizability to female populations. Though limited, current evidence suggests that females may require a greater number of heat acclimation sessions or greater thermal stress to achieve the same magnitude of physiological adaptations as males. The underlying mechanisms explaining the temporal sex differences in the physiological adaptations to heat acclimation are currently unclear. Therefore, the aims of this state-of-the-art review are to: (i) present a brief yet comprehensive synthesis of the current female and sex difference literature, (ii) highlight sex-dependent (e.g. anthropometric, menstrual cycle) and sex-independent factors (e.g. environmental conditions, fitness) influencing the physiological and performance adaptations to heat acclimation, and (iii) address key avenues for future research.
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Abbreviations
- E max :
-
Maximum evaporative capacity of the environment
- E req :
-
Evaporative heat-loss requirement
- HA:
-
Heat acclimation
- HR:
-
Heart rate
- HSP:
-
Heat shock proteins
- HSP72:
-
Heat shock protein 72
- MTHA:
-
Medium-term heat acclimation
- LTHA:
-
Long-term heat acclimation
- RH:
-
Relative humidity
- SR:
-
Sweat rate
- STHA:
-
Short-term heat acclimation
- T core :
-
Core temperature
- T skin :
-
Skin temperature
- \(\dot{V}{\text{O}}_{{2{\text{max}}}}\) :
-
Maximal oxygen uptake
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Funding
This research was supported by the Natural Science and Engineering Research Council of Canada (NSERC) through a Canada Graduate Scholarship—Doctoral (KAW), Postgraduate Scholarship—Doctoral (PJW), and Discovery Grant (SSC, 2018-04077). KAW and PJW were also supported by Brock University Research Training Awards.
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KAW conceived the review topic. KAW, PJW and SSC designed the review, drafted and revised the manuscript. All authors approved the final version of the manuscript.
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Wickham, K.A., Wallace, P.J. & Cheung, S.S. Sex differences in the physiological adaptations to heat acclimation: a state-of-the-art review. Eur J Appl Physiol 121, 353–367 (2021). https://doi.org/10.1007/s00421-020-04550-y
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DOI: https://doi.org/10.1007/s00421-020-04550-y