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影响。在撒哈拉以南非洲(SSA)，过热已经构成了令人担忧的健康危害。人类必须将核心体温保持在37摄氏度左右才能保持健康。当暴露在高温下时，有效的反应可以被激活，以促进身体的热量损失，例如通过增加皮肤灌注量和/或增加出汗率。然而，这些反应可能会对身体造成沉重的压力--特别是当与高强度的体力工作结合在一起时，这通常发生在户外耕作活动中。这种长期暴露在高温下的压力会导致精疲力竭，在严重的情况下，会导致热损伤或死亡。当工作必须在炎热潮湿的环境条件下进行时，更有可能出现这种情况。由于SSA的大部分日常工作是自给自足的农业，任何生产力的降低都会导致额外的严重的经济、社会和健康后果，因此在第一阶段，我们调查了SSA年轻的健康农民经历的热应激及其对健康和生产力的影响。湿球温度(WBGT，°C)是导致热应激的主要环境因素，而生理应激指数使用生理数据，即心率和核心体温，来确定身体上的热应激。然而，对热变化的脆弱性很大程度上取决于个体特征，因此先前存在的健康状况起着关键作用。由于非传染性疾病在南非是一个新出现的问题，其患病率可能被低估，在第二阶段，我们将重点关注受慢性呼吸道疾病影响的农民，如慢性阻塞性肺疾病(COPD)和哮喘。我们的目标是确定气候变化对SSA这一脆弱人群劳动能力的具体生理影响：考虑季节和地理差异，量化先前存在的疾病的额外不利影响，评估与性别相关的差异，并确定作为行为干预措施的成本效益适应策略是否可行。为了更深入地了解生产率，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：收获的热量(H2H)。氢化氢研究将利用RU方法，将已在各个项目中使用的方法结合起来，将高温胁迫、住房降温干预措施、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，广泛的研究从总体上描述了气候变化对农业生产的不利影响，并提出了各种农业技术变化，但据我们所知，SSA从未研究过对农民工作能力的影响。

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.