Managing and mitigating heat to improve health and performance in females

Climate change refers to the long-term shift in global temperatures, which may occur naturally, but human activities relating to burning fossil fuels is considered a main driver.

As a result, the frequency and intensity of heat waves is increasing, exposing humans to unseasonable and dangerously high temperatures which harms human health. In the UK during the five heat-periods in 2022, where temperatures exceeded 40 degree Celsius, 3,271 excess deaths were reported which is estimated to increase to over 7,000 by 2050. Furthermore, audits reveal six cases of heat illness per 100,000 in an occupational setting, two cases per 1,000 in military personnel, and nine cases per 100 in athletes.

Heat illnesses are largely avoidable with the implementation of appropriate, effective, accessible, and sustainable heat mitigation strategies combined with appropriate education for more susceptible individuals.

Males and females differ in their responses to heat stress (i.e., external heat load) largely due to females having a reduced sweating capacity, especially during periods of high heat loss requirements (i.e., during high intensity exercise). As such, females may reach dangerously high body temperatures quicker than males and consequently, have been more frequently diagnosed as heat intolerant. Hormonal fluctuations associated with the menstrual cycle modify responses to heat strain. For example, elevated progesterone concentrations during the luteal phase of the menstrual cycle (i.e., after ovulation before next period) increases resting body temperature, the onset threshold for sweating and the shift of blood to the skin surface for heat dissipation.

Furthermore, perimenopausal and menopausal females experience additional heat sensitives, with the occurrence of hot flushes and night sweats which elevate their thermal discomfort. Despite known sex differences, audits reveal an under-representation of females as study participants, as such, heat mitigation guidelines, are underpinned almost exclusively by research conducted in men, without consideration of issues associated with the biological and phenotypical sex differences.

The overarching aim of this project is to support females to navigate extreme heat episodes. We will assess more sustainable and accessible methods compared to current consensus. We will then generate bespoke female heat mitigation guidelines and distribute these to the public through available platforms to improve females' health and performance. This programme of work will aim to advance our current knowledge on how to best prepare females who are exposed to unseasonably high temperatures during a heat wave or are relocated to hot and hot/humid climates for occupational and sporting activities.