On January 27, 2026, as temperatures soar across Australia, the question of exercising in extreme heat has become increasingly relevant. Sixty-one-year-old Ballarat runner David Fraser maintains his rigorous training schedule year-round, including during the summer heat. “Over summer, it would be rare to alter any of the routines. By keeping them the same, the body learns to adapt in all conditions,” he explains. However, he notes that he would adjust his routine only in cases of lightning or dangerous winds.
While Fraser enjoys exercising in the heat and only occasionally experiences muscle cramps due to sodium loss, experts caution against the potential risks of maintaining a normal exercise routine in high temperatures. This article explores the implications of exercising in the heat, safety tips, and the potential benefits of heat acclimation.
Understanding the Risks of Exercising in Heat
According to Sam Chalmers, a senior lecturer in human movement at Adelaide University, the body has mechanisms to increase heat loss during exercise, such as increased sweat rate and skin blood flow. However, in hot and humid conditions, these mechanisms may not suffice. “Exercise challenges the maintenance of our normal core temperature because it generates a huge amount of internal body heat while we are also combating heat gain from the hot external environment,” Chalmers explains.
The Royal Australian College of General Practitioners President, Dr. Michael Wright, warns of the increased risk of exertional heat illness, which can range from mild heat stress to potentially deadly heat stroke. “Symptoms of heat stress or heat exhaustion include dizziness, nausea, and fatigue. More severe symptoms, such as confusion, collapse, or cessation of sweating, indicate heat stroke and require emergency care,” he advises.
Who is More at Risk?
While anyone can be affected by hot weather, certain groups are more vulnerable. These include adults over 65, pregnant women, children, and individuals with chronic health conditions such as heart, lung, and kidney diseases, as well as diabetes. “These groups may become unwell at lower temperatures,” Wright notes.
Exercising During a Heatwave
A heatwave, defined as three or more days of unusually high temperatures, can exacerbate the effects of heat. In such scenarios, Wright recommends avoiding outdoor exercise. Sydney-based runner and exercise physiologist Veronika Larisova opts for early morning or late evening sessions to avoid peak heat. “I alter my routine because I love being outdoors, but I don’t enjoy running in extreme heat in the middle of the day,” she says.
Larisova also reduces workout intensity and changes exercises during higher temperatures. “Consistency over time matters more than any single session,” she emphasizes.
Potential Benefits of Exercising in Heat
Despite the risks, there can be benefits to exercising in warmer weather if done safely. Chalmers explains that regular exercise in heat can lead to heat acclimation, resulting in physiological adaptations that increase heat tolerance. These adaptations include increased sweat rate, enhanced skin blood flow, greater body fluid volume, and a lower heart rate for the same exercise intensity.
“Regular exercise in the heat will result in the process of heat acclimation, which is a set of physiological adaptations that increase tolerance to the heat,” says Chalmers.
Fraser has experienced these benefits, noting that running in the heat is akin to altitude training. “The blood volume in your body increases, and your heart starts pumping more efficiently, which increases oxygen to your muscles,” he says.
Tips for Safe Exercise in Heat
For those choosing to exercise in the heat, preparation and planning are crucial. Jamie Crain, CEO of Sports Medicine Australia, advises drinking plenty of water before, during, and after exercise, taking breaks as needed, and wearing lightweight, breathable clothing. He also suggests using the Sports Heat Tool to assess heat-related risks for different sports.
“The heat risk tool can be used to inform decisions around when and how hard you might like to exercise and when additional cooling strategies might be required,” Chalmers adds.
As temperatures continue to rise, understanding the balance between the risks and benefits of exercising in the heat is essential. By taking appropriate precautions, individuals can safely enjoy their fitness routines while minimizing health risks.
