Dr Hannah surveyed more than 500 people who worked outdoors and recorded onsite temperatures to find out when people started exhibiting signs of heat stress, including cramping, headaches and vomiting.
"Queensland tradies exhibit signs of heat stress during periods of high humidity," she said.
She said high humidity at 26C could cause tradies heat stress, and if the humidity hit above 60 per cent, tradies should start restricting their activities.
"At high-level humidity [70 per cent and above] all activities should be cancelled," Dr Hannah said.
