Climate change, heat stress and its impact on health and work capacity in vulnerable groups

气候变化加剧了极端高温事件的暴露。在撒哈拉以南非洲（SSA），过热已经对健康造成了令人担忧的危害。人类必须保持一定的核心体温约37 °C，以维持健康。当暴露于热时，例如通过增加皮肤灌注和/或增加出汗率，可以激活有效的响应以促进身体的热损失。然而，这些反应可能会对身体造成沉重的压力-特别是当与密集的体力劳动相结合时，这通常发生在户外农业活动中。这种应变与长期的热暴露可导致疲惫和严重的形式，将导致热损伤或死亡。当工作必须在炎热和潮湿的环境条件下进行时，这甚至更有可能。由于SSA的大部分日常工作量是自给农业，生产力的任何降低都会引起一些额外的严重经济，社会和健康后果，因此在第一阶段，我们调查了SSA年轻健康农民所经历的热应激及其对健康和生产力的影响。湿球地球仪温度（WBGT，°C）说明了导致热应激的主要环境因素，而生理应变指数使用生理数据，即，心率和核心体温，以确定对身体的热应变。然而，对热变化的脆弱性在很大程度上取决于个人特征，因此预先存在的健康状况起着关键作用。由于非传染性疾病是撒南非洲一个新出现的问题，其流行率可能被低估，在第二阶段，我们将重点关注患有慢性呼吸道疾病，如慢性阻塞性肺病和哮喘的农民。我们的目标是确定特定的生理影响的气候变化对劳动力的能力在这个脆弱的人口在SSA：占季节和地理差异，量化的额外的不利影响的预先存在的疾病，评估性别相关的差异，并确定是否具有成本效益的适应策略，作为行为干预措施，是可行的。为了更深入地了解生产力，我们的团队将在研究单位（RU）内协调一项新构思的集群间研究：收获热量（H2 H）。H2 H研究将利用RU方法，将各个项目中已经使用的方法结合起来，将热应激、住房降温干预、收获期间的工作模式、产量/质量和儿童营养不良联系起来。在文献中，广泛的研究描述了气候变化对农业生产的不利影响，并提出了农业技术的各种变化，然而，据我们所知，对农民工作能力的影响从未在撒南非洲进行过研究。

Climate change intensifies exposure to extreme heat events. In Sub-Saharan Africa (SSA) excessive heat already presents an alarming health hazard. Human beings have to keep to a certain core body temperature of about 37 °C to maintain health. When exposed to heat, effective responses can be activated to facilitate heat losses from the body, by increasing skin perfusion and/or increasing the sweat rate for example. However, those reactions can cause heavy strain on the body – especially when combined with intensive physical work, which typically occurs during outdoor farming activities. Such strain with prolonged heat exposure can cause exhaustion and in severe forms, will lead to heat injuries or death. This is even more likely when the work has to be performed under hot and humid environmental conditions. As most of the daily workload in SSA is subsistence agriculture, any reduction in productivity will induce several additional severe economic, social, and health consequences, thus in the first phase, we investigated the heat stress experienced by young healthy farmers in SSA and its impact on health and productivity. Whereas the Wet Bulb Globe Temperature (WBGT, °C) accounts for the major environmental factors responsible for heat stress, the Physiological Strain Index uses physiological data, i.e., heart rate and core body temperature, to determine the heat strain on the body. However, vulnerability to heat changes largely varies as a function of individual characteristics, thus pre-existing health conditions play a key role. As non-communicable diseases are an emerging issue in SSA, whose prevalence may be underestimated, during this second phase we will focus on farmers affected by chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma. We aim at determining the specific physiological impacts of climate variations on labor capacity in this vulnerable population in SSA: accounting for the seasonal and geographical differences, quantifying the additional adverse effect of the pre-existing disease, assessing sex-related differences and determining whether cost-effective adaptation strategies, as behavioral interventions, are feasible. Looking deeper at the productivity, our team will coordinate within the Research Unit (RU) a newly conceived inter-cluster study: the Heat to Harvest (H2H). The H2H study will leverage the RU approach, by integrating the methods already in use within individual projects, linking heat stress, housing cooling interventions, working pattern during harvest, yields quantity/quality and children undernutrition. In the literature a wide range of studies have described the adverse effect of climate change on agricultural production in general and propose various changes in agricultural techniques, however, the impact on the farmers’ work capacity has never been studied in SSA, to the best of our knowledge.