Bakers are among the professions at risk from heat-related health problems, a study has revealed.

The study, Workers’ health and productivity under occupational heat strain: a systematic review and meta-analysis, found that one in three individuals working in hot conditions experienced hyperthermia or more serious symptoms of heat illness.

Researchers analysed data from more than 447 million workers from over 40 different occupations –including bakers, miners, kitchen staff, fruit and crop pickers and firefighters – across the globe.

They found that individuals working under heat stress had an average body temperature of 37.6°C, much higher than the 36.9°C for those working in normal conditions.

The at-risk group was four times more likely to experience heat strain, a condition with important effects for the body’s physiological function that includes symptoms such as elevated hyperthermia, dehydration, kidney injury, nausea, fainting, and muscle cramps.

It also showed that hot conditions affected productivity. Of those who worked under heat stress, 30% reported productivity losses.

“Our study demonstrates the important impacts of occupational heat strain on health and productivity and should be recognised globally as a public health problem,” said Professor George Havenith, director of Loughborough’s Environmental Ergonomics Research Centre, who was part of the research team.

“Together with other organisations, we are working towards implementing actions to mitigate its effects, especially in light of the occurring climate change and the anticipated rise in heat stress.”

He added their aim was to establish a global surveillance system that would guide public health policy, as well as health and safety planning.