Improving females' health and performance by mitigating heat strain

气候变化指的是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的危险高温中，这损害了人类的健康。在2022年气温超过40摄氏度的五个炎热期，英国报告了3271人多死，预计到2050年将增加到7000人以上。此外，审计显示，职业环境中每10万人中有6例中暑，军事人员每1000人中有2例中暑，运动员每100人中有9例中暑。通过实施适当的、有效的、可获得的和可持续的消暑策略，结合对更易感人群的适当教育，中暑疾病基本上是可以避免的。为了为中暑压力做准备，共识建议个人应该在高温下锻炼，最多锻炼14次，时间为60分钟，此时核心和皮肤温度会升高，并开始出汗(racinais等人，2015)。这需要搬迁到炎热的气候或进入环境室，这可能是昂贵和不切实际的。空调的广泛使用是另一种被广泛使用的方法，以帮助缓解热压力。然而，在贫困地区和涉及外部活动的职业中，一些最脆弱的人无法使用空调。总体而言，这些降温战略增加了温室气体排放，加剧了全球变暖，并增加了未来极端高温事件的风险(莱恩2021)。更好地理解和使用更可持续、更容易获得、更省时、更易于管理的缓解热应变的技术，如采用热水浸泡、使用电风扇冷却、湿润皮肤和冷水浸泡，已成为一项紧迫的研究重点。男性和女性对热应激(即外部热负荷)的反应不同，这主要是因为女性的出汗能力降低，特别是在高热量损失要求的时期(即，在高强度运动期间)。因此，女性体温可能比男性更快达到危险的高温，因此，更多地被诊断为热耐受。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(即在下一次月经前排卵后)，黄体酮浓度升高会增加静息体温、出汗的开始阈值以及血液转移到皮肤表面以散热。此外，围绝经期和更年期女性会经历额外的热敏感，出现潮热和盗汗会加剧她们的热不适。尽管已知性别差异，但审计显示，女性作为研究参与者的代表性不足，因此，降温指南几乎完全基于男性进行的研究，而没有考虑与生物和表型性别差异相关的问题。这项建议的主要目的是支持女性应对极端高温。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高温和冷却皮肤以管理高温。然后，我们将制作定制的女性降温指南，并通过现有平台分发给公众，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.