Excessive heat while working, generally at temperatures above 35° Celsius, creates occupational health risks and reduces work capacity and labour productivity (Parsons, 2014). Maintaining a core body temperature close to 37°C is essential for health and human performance, and large amounts of sweating as a result of high heat exposure while working creates a risk of dehydration. Excessive body temperature and/or dehydration causes “heat exhaustion”, slower work, more mistakes while working, clinical heat effects (heat exhaustion, heat stroke, and even death; Bouchama and Knochel, 2002) and increased risk of accidental injuries (Schulte and Chun, 2009). These health effects lessen labour productivity, whether the worker is in paid work in a range of industries, in traditional subsistence agriculture or farming, or in other daily life activitie. Daily family activities, such as caring for children or the elderly, are equally affected.