Heatwaves and mortality in Africa
South Africa | Infants, the elderly, persons living with disabilities, pregnant women, outdoor workers, and those who are on chronic medications were identified as the people most vulnerable to deaths as a result of exposure to extreme heat.
This is according to research conducted by the South African Medical Research Council (SAMRC) and its partners. The research draws a correlation between the way in which the biological, environmental, medical, socio-behavioural and geographical effects of extreme heat exposure have had an adverse impact on morbidity and mortality in the most vulnerable communities in Africa.
Drawn from evidence from 1992 to 2019, and published in 2022, the research aimed to provide a synthesis of Africa-informed evidence on the effects of extreme heat on morbidity and mortality on the continent.
The majority of studies on the relationship between extreme heat exposure, and morbidity and mortality have been carried out in high-income countries,” says Dr Caradee Wright who is a Chief Specialist Scientist at the SAMRC’s Environment and Health Research Unit (EHRU). Wright, also a Principal Investigator on the review, adds that there are major gaps in knowledge about the effects of heatwaves on health outcomes among different sub-groups in low and middle-income countries and the few existing studies that address this topic for Africa largely focus on other continents and include selected African countries only as an add-on.
Complementing her research on the impact of extreme heat on mortality and morbidity in Africa, the SAMRC’s EHRU conducted a study specific to heat resilience and coping mechanisms related to indoor and outdoor temperatures among 406 households in the Limpopo province in South Africa where temperatures rose to above 40°C outdoors and 36°C indoors. According to the study, published in the South African Journal of Psychology, most people perceived their homes to be too hot when temperatures were high outdoors and relied on recommended heat-health actions such as sitting outdoors in the shade or opening windows to try and keep cool.
“Resilience to heatwaves as a result of climate change requires more than personal action,” says Dr Wright. “In light of climate threats and climate-related disaster risks facing South Africa, an all-encompassing approach, including education campaigns, climate-proofed housing, access to basic services, and financial considerations that will help support resilient coping among South Africans is urgently required.”
According to the study, preparedness and resilience are key as South African temperatures are expected to become warmer than the projected global average temperature. Some parts of the country will experience drying and other parts will become wetter, and there aren’t any certainties as to how much exactly and where temperatures will reach extremes such as heatwaves.
Although there is no universally accepted definition of a heatwave, they are typically described as a consecutive period of hot days with temperatures above a given threshold. They are not based on a health outcome, specifically to avoid morbidity or mortality from heat extreme. There is also evidence showing that global warming will lead to more frequent and more extreme weather events such as heatwaves.
"The current extreme heat and heatwaves being experienced in January 2023 in South Africa pose a serious and concerning health threat to South Africans. We should take precautions such as drinking water regularly, if possible cooling arms and feet in a basin of water, using shade when outdoors and wearing a hat”, Wright says. Where possible, avoiding being outdoors during the hottest time of the day in the afternoon is advised, however, this might not be possible for outdoor workers. Outdoor workers should wear cool clothing and hats, and drink plenty of water to keep hydrated.
Heat affects the human body by reducing its ability to regulate its temperature and keep cool by sweating. As the body becomes too hot, a person may experience heat cramps, heat exhaustion, heat stroke and even hyperthermia. Irritability, lack of concentration, headaches and loss of ability to do skilled tasks or heavy work. People vulnerable to heat such as infants, the elderly, persons living with disabilities, pregnant women, outdoor workers, and those who are on chronic medications – either lack the ability to self-regulate their internal ‘thermostat’, or are faced with excess heat exposure as is the case for people working outdoors. It is essential that outdoor workers and their employers are trained to recognise the symptoms of heat illnesses and impacts.
Tips to keep children and the elderly safe in hot weather
Tendani Tsedu
Head of Corporate & Marketing Communication
Email: tendani.tsedu@mrc.ac.za