On January 27, 2026, as temperatures soar across Australia, the question of whether to maintain regular exercise routines in the heat becomes a pressing concern. For 61-year-old Ballarat runner David Fraser, the answer is clear. His weekly training includes four morning gym sessions and five trail runs, ranging from 10 to 33 kilometers, regardless of the season.
“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. “The only time things would change is if there were lightning or very dangerous winds.”
The Science Behind Exercising in Heat
While Fraser enjoys exercising in the heat, experts warn of potential risks. Sam Chalmers, a senior lecturer in human movement at Adelaide University, explains that while the body has mechanisms to manage heat loss during exercise, extreme conditions can overwhelm these systems.
“Stressful sport and exercise in hot and humid conditions may mean that the body is unable to defend against substantial rises in core temperature,” Chalmers notes. “This can lead to symptoms ranging from headaches and faintness to severe issues like central nervous system dysfunction and organ damage.”
Dr. Michael Wright, President of The Royal Australian College of General Practitioners, adds that the risk of exertional heat illness increases in such conditions.
“Symptoms of heat stress or heat exhaustion include dizziness, nausea, and fatigue. Severe symptoms, such as confusion, collapse, or cessation of sweating, indicate heat stroke and require emergency care,” he warns.
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 like heart, lung, and kidney disease, or diabetes.
Exercising During a Heatwave
Heatwaves, defined as three or more consecutive days of unusually high temperatures, exacerbate these risks. Dr. Wright recommends avoiding outdoor exercise during such periods.
“Sometimes skipping or postponing exercise is the safest option,” he advises.
Sydney-based runner and exercise physiologist Veronika Larisova adjusts her routine to avoid peak heat, opting for early morning or late evening sessions.
“Extreme heat places additional stress on the cardiovascular system and thermoregulation, so maintaining the same intensity, duration, or timing year-round isn’t always appropriate or safe,” she says.
The 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 the heat can lead to heat acclimation, a set of physiological adaptations that increase heat tolerance.
“These adaptations include increased sweat rate, enhanced skin blood flow, greater body fluid volume, a lower heart rate for the same exercise intensity, and a general perception of feeling more comfortable in the heat,” he says.
Fraser has experienced these benefits firsthand.
“Running in the heat is like altitude training. It increases blood volume and heart efficiency, boosting oxygen to muscles,” he shares. “Your mental strength improves, and you get a huge endorphin fix.”
Safety Tips for Exercising in Heat
For those choosing to exercise in the heat, preparation is key. Jamie Crain, CEO of Sports Medicine Australia, emphasizes the importance of hydration and breaks.
“Drink plenty of water before and during exercise, take breaks as needed, and ensure access to shade or shelter,” he advises.
Crain also 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 for various sports.
“Our tool integrates factors like internal heat production, clothing levels, and local weather to estimate heat stress risk for over 40 sports,” explains Professor Ollie Jay, Academic Director of the Heat and Health Research Centre.
Chalmers concurs, noting that different sports have varying risk profiles based on intensity and environment.
“The heat risk tool can guide decisions on exercise intensity and when additional cooling strategies might be needed,” he says.
As the summer continues, understanding the balance between risk and benefit is crucial for those committed to maintaining their fitness routines in the heat.
