Heat exposure and agricultural workers' health: A global systematic review with implications for Peri-urban and semi-urban Southeast Asia

Agricultural workers are among the most climate-vulnerable populations, particularly in tropical and low- to middle-income regions. Using the PRISMA framework, this systematic review analysed 97 studies from 27 countries on the health impacts of high temperatures in agricultural settings. The review also further discusses on Southeast Asia, where rapid urbanisation is increasingly shifting agricultural labour into semi-urban and peri-urban zones. The majority of reviewed studies were conducted in North America (54.6%), with the United States alone contributing 38.1%. Despite the high vulnerability of agricultural populations in regions like Africa, South America, and Asia, these areas remain significantly underrepresented in the literature on heat exposure and agricultural worker health. Common health outcomes included self-reported Heat-related illnesses (27.8%) and kidney issues (20.6%), followed by physiological strain (14.4%), occupational injuries (10.3%). However, critical health domains such as cardiovascular health (7.2%), mortality (3.1%), mental well-being and other symptoms (less than 2%) remain significantly understudied. Over one-third of studies relied on recalled exposure without direct heat measurement, while others used ambient temperature, WBGT, or composite thermal indices to quantify heat stress. In Southeast Asia, nine studies reported consistent risks of HRI, kidney strain, and physiological stress, but none focused specifically on peri-urban agricultural workers. Rapid urbanisation has created transitional peri-urban zones where agricultural workers increasingly reside. These areas often lack formal infrastructure, healthcare access, and regulatory protections, exacerbating exposure to extreme heat, particularly through the urban heat island effect. Addressing these gaps requires integrating labour protections into urban climate strategies and developing context-specific interventions for vulnerable agricultural communities. • Review of 97 studies on heat and health risks in agricultural settings globally. • 38.1% of studies came from the U.S.; Asia and Africa remain underrepresented. • Heat-related illness and kidney issues were the most common health outcomes. • Cardiovascular, mental health, and mortality impacts remain understudied. • Urbanisation in Southeast Asia increases heat risk in peri-urban farm zones.