Exposure to moderate and extreme temperatures may significantly increase the risk of injuries at the workplace, according to a study.
The study, published in the journal Environmental Health Perspectives, is the first to analyse data from an entire country and evaluate the economic impact.
Researchers from the Barcelona Institute for Global Health (ISGlobal) analysed data related to nearly 16 million occupational injuries in Spain between 1994 and 2013 that resulted in at least one day of sick leave.
The information was analysed in relation to the daily temperatures in the province where each injury occurred.
"Exposure to moderate to extreme temperatures may have played a role in over half a million of the workplace injuries that occurred during the study period," said Erica Martinez, a researcher at ISGlobal.
The analysis found that, on average, some 60 temperature-related injuries leading to at least one lost workday occurred each day, accounting for 2.7 per cent of all work-related injuries in Spain.
Extremes of cold and heat increased the risk of injury by four per cent and nine per cent, respectively.
The biological mechanisms that link exposure to extreme ambient temperatures with the risk of occupational injury "are not yet fully understood," said Martinez.
The most common types of injuries analysed in the study were bone fractures and superficial injuries.
"This suggests that the underlying mechanism could be related to impaired concentration or judgement, which would affect occupational safety," Martinez said.
Temperature-related effects were not limited to the day of exposure; a "pattern of delayed impact," possibly caused by cumulative fatigue and dehydration, was observed in the days following exposure.
The study also concluded that women appear to be more vulnerable to cold and men more vulnerable to heat.
This difference could be explained by the fact that women have lower sweat rates than men in hot climates, researchers said.
The youngest workers were the most vulnerable to heat, possibly because they tend to do more physically demanding work, they said.
As for the economic impact of non-optimal temperatures, the study found that temperature-related loss of working days had an annual cost of more than 360 million euros, representing 0.03 per cent of Spain's gross domestic product in 2015.
Moderately high temperatures contributed the most to the economic losses, researchers said.