Improving females' health and performance by mitigating heat strain

气候变化是指全球气温的长期变化，这可能是自然发生的，但与燃烧化石燃料有关的人类活动被认为是主要驱动因素。因此，热浪的频率和强度正在增加，使人类暴露在不合时宜和危险的高温下，危害人类健康。在英国，在2022年的五个高温时期，气温超过40摄氏度，报告了3271例额外死亡，估计到2050年将增加到7000多人。此外，审计显示，职业环境中每10万人中有6例中暑，军事人员中每1 000人中有2例，运动员中每100人中有9例。通过实施适当的、有效的、可获得的和可持续的热缓解策略，并结合对易感人群的适当教育，热疾病在很大程度上是可以避免的。为了应对热应激，一致建议个人应该在高温下锻炼14次，每次60分钟，此时核心和皮肤温度升高，开始出汗（Racinais et al., 2015）。这需要搬迁到一个炎热的气候或进入环境室，这可能是昂贵的和不切实际的。空调的广泛使用是另一种被广泛用于帮助缓解热紧张的方法。然而，在贫困地区和从事户外活动的职业中，一些最脆弱的人无法使用空调。总的来说，这些减热战略增加了温室气体排放，导致全球变暖，并增加了未来极端高温事件的风险（Lane 2021）。如何更好地理解和利用更可持续、更方便、更省时、更易于管理的减轻热应变的技术，如适应使用热水浸泡、使用电风扇冷却、润湿皮肤和冷水浸泡，已成为一个迫切的研究重点。男性和女性对热应激（即外部热负荷）的反应不同，主要是由于女性的排汗能力较低，特别是在需要高热量损失的时期（即高强度运动期间）。因此，女性可能比男性更快达到危险的高体温，因此，更经常被诊断为热不耐受。与月经周期相关的荷尔蒙波动改变了对热应激的反应。例如，在月经周期的黄体期（即排卵后的下一个月经期之前），黄体酮浓度升高会增加静息体温、出汗的开始阈值和血液向皮肤表面转移以散热。此外，围绝经期和绝经期女性会经历额外的热敏反应，出现潮热和盗汗，这加剧了她们的热不适。尽管存在已知的性别差异，但审计显示，女性作为研究参与者的代表性不足，因此，减热指南几乎完全是基于对男性进行的研究，而没有考虑与生物学和表型性别差异相关的问题。这项提议的首要目的是帮助雌性度过极端炎热的时期。与目前的共识相比，我们将评估更可持续和更容易获得的方法，例如，热水浸泡以适应热量并冷却皮肤以控制热量。然后，我们将生成定制的女性散热指南，并通过现有平台向公众分发这些指南，以改善女性的健康和表现。

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.To prepare for heat stress, consensus recommendations suggest individuals should exercise in the heat, for up to 14 occasions for >60-min, where core and skin temperatures are elevated and sweating is initiated (Racinais et al., 2015). This requires relocation to a hot climate or access to an environmental chamber, which can be costly and impractical. The widespread use of air conditioning is another approach widely used to help mitigate heat strain. However, the use of air conditioning is not accessible to some of the most vulnerable, in areas of poverty, and in occupations involving outside activity. Collectively, these heat mitigation strategies increase greenhouse gas emissions contributing to global warming and increasing the risk of future extreme heat events (Lane 2021). An improved understanding and utility of techniques for mitigating heat strain that are more sustainable, accessible, time efficient, and simple to administer such as adapting using hot water immersion, and cooling using electric fans, wetting the skin and cold-water immersion, has become an urgent research priority. 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 proposal is to support females to navigate extreme heat episodes. We will assess more sustainable and accessible methods compared to current consensus, e.g., hot water immersion to adapt to the heat and cooling the skin to manage the heat. We will then generate bespoke female heat mitigation guidelines and distribute these to the public through available platforms to improve females' health and performance.