The study reveals predicted changes in climate might impact people’s ability to work outdoors in Australia at different times of the year.
Using an international standard heat measure, the wet bulb globe temperature (WBGT), which is used to assess physical activity limits by combining meteorological data and a military heat categorisation system, researchers assessed different climate scenarios across Australia.
“It was found that in the next 20 to 60 years, physical activity will become more restricted across a larger area of Australia,” Associate Professor Dr Andrew Hall said.
“As the climate warms, we might have to implement new ways of managing physical outdoor work across much of the continent.”
Dr Hall suggested taking longer breaks across longer periods of the day and requiring breaks during more months of the year as solutions.
Unchecked heat exposure combined with physical activity can lead to incapacitating heat illnesses and, in the most serious of cases, life-threatening heatstroke.
“At-risk groups in Australia include miners, athletes, farm workers and defence personnel,” Dr Hall said.
“The research shows there’s a need for greater understanding about human physical activity limits and the risk exposure to heat-related injury, above the current highest heat categories used to inform outdoor work practices, to prepare for a warmer climate.”
The WBGT, developed by the United States military in the 1970s, is commonly used to determine heat categories that recommends limits on physical activity.
Dr Hall said his research showed the rate of increase in WBGT over the next 50 years would move many areas of Australia into more restrictive categories.
For example, modelling indicates that moderate physical activity (such as brisk walking or gardening), which under Category 2 conditions can continue for 150 minutes in any four-hour period with minimal risk of heat injury, will, under Category 3, be reduced to 100 minutes.