Heat-related injuries in the workplace aren’t tied exclusively to extreme weather conditions, a study from the National University of Singapore (NUS) has found, with researchers calling on employers to protect their workers all year round.

The acceptable core temperature of a person’s internal organs is 37°C, but the NUS study of 160 construction workers found that some exceeded 38°C and exhibited an elevated heart rate, even when working indoors during cooler parts of the year.