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

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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.