On January 27, 2026, as temperatures soar, the question of how to safely exercise in the heat becomes increasingly relevant. Sixty-one-year-old Ballarat runner David Fraser exemplifies resilience, maintaining his rigorous training schedule of four morning gym sessions and five trail runs weekly, even as summer temperatures rise. “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, from very cold to extremely hot,” Fraser explains. However, he acknowledges that extreme weather conditions like lightning or dangerous winds might prompt changes.
While Fraser enjoys exercising in the heat and reports only minor issues like muscle cramps from sodium loss, the broader question remains: how safe is it to maintain a regular exercise routine in high temperatures?
Understanding the Risks of Exercising in the 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 sweating and increased blood flow to the skin. However, “stressful sport and exercise in hot and humid conditions may mean that the body is unable to defend against substantial rises in core temperature,” he notes. This can lead to symptoms ranging from headaches and faintness to severe issues like central nervous system dysfunction and organ damage.
The Royal Australian College of General Practitioners President, Dr. Michael Wright, warns of the risks 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. With more severe symptoms, such as confusion, collapse, or cessation of sweating, those are signs of heat stroke, and they need emergency care,” he advises.
Who is More at Risk?
While anyone can be affected by hot weather, certain groups are more vulnerable, including adults over 65, pregnant women, children, and those with chronic health conditions like heart, lung, and kidney diseases, or diabetes. These individuals may become unwell at lower temperatures, making it crucial to take precautions.
Exercising During a Heatwave
Heatwaves, defined as periods of three or more days with unusually high temperatures, exacerbate the effects of heat. In such scenarios, Dr. Wright recommends avoiding outdoor exercise altogether. Sydney-based runner and exercise physiologist Veronika Larisova opts for early morning or late evening sessions to avoid peak heat, adjusting her routine to ensure safety.
“I do alter my routine because I love being outdoors, but I don’t enjoy running in extreme heat in the middle of the day or early afternoon,” Larisova shares. She also reduces workout intensity and changes exercises when temperatures rise. “Consistency over time matters more than any single session,” she emphasizes.
Benefits of Exercising in the Heat
Despite the risks, there can be benefits to exercising in warmer weather if done safely. Chalmers explains, “Regular exercise in the heat will result in heat acclimation, a set of physiological adaptations that increase tolerance to the heat.” These adaptations include increased sweat rate, enhanced skin blood flow, greater body fluid volume, and a lower heart rate for the same exercise intensity.
Fraser has experienced these benefits firsthand, noting improvements in cardiovascular efficiency and mental strength. “Running in the heat was the equivalent of doing altitude training,” he says, highlighting the increased blood volume and efficient heart function.
Tips for Safe Exercise in Hot Conditions
For those choosing to exercise in the heat, planning and preparation are essential. Jamie Crain, CEO of Sports Medicine Australia, advises, “Drinking lots of water prior to exercising is important, ensuring access to water during exercise, taking breaks as needed, and adjusting clothing to lightweight, breathable fabrics.”
Crain recommends using the Sports Heat Tool, developed by SMA and the University of Sydney’s Heat and Health Research Centre, to assess heat-related risks. Professor Ollie Jay, Academic Director at the Centre, explains, “Our tool integrates factors like internal heat production, clothing levels, and local weather to estimate heat stress risk for over 40 sports.”
Chalmers concurs, noting that different sports have varying risk profiles based on intensity and environment. “The heat risk tool can inform decisions on exercise intensity and when additional cooling strategies are needed,” he says.
As temperatures continue to rise, understanding how to exercise safely in the heat becomes crucial. By taking appropriate precautions and leveraging expert tools, individuals can maintain their fitness routines without compromising their health.
