In the height of summer, when temperatures soar, many athletes and fitness enthusiasts face the challenge of maintaining their exercise routines. Sixty-one-year-old Ballarat runner David Fraser is no exception. His weekly training regime 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.
However, the question arises: how safe is it to continue your normal exercise routine when it’s hot? While Fraser enjoys exercising in the heat and has only experienced minor issues like muscle cramps from sodium loss, experts warn of potential risks.
Understanding the Risks of Exercising in Heat
Sam Chalmers, a senior lecturer in human movement at Adelaide University, highlights the body’s natural mechanisms to manage heat during exercise. “The body increases sweat rate and skin blood flow to lose heat,” he says. However, in hot and humid conditions, these strategies may not suffice, leading to dangerous rises in core temperature.
“This can mean comparatively minor symptoms such as headaches and feelings of faintness, through to more severe issues such as central nervous system dysfunction, loss of consciousness, and organ damage,” Chalmers notes.
The Royal Australian College of General Practitioners President, Dr. Michael Wright, adds that exertional heat illness can range from mild heat stress to potentially deadly heat stroke. “Symptoms of heat stress or heat exhaustion include dizziness, nausea, and fatigue. Severe symptoms like confusion, collapsing, or stopping sweating despite the heat indicate heat stroke and require emergency care,” he warns.
Who is More Vulnerable?
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 diseases, and diabetes. “These groups may become unwell at lower temperatures,” Wright explains.
Exercising During a Heatwave
A heatwave, typically defined as three or more days of unusually high temperatures, exacerbates the risks. In such scenarios, Wright advises avoiding outdoor exercise altogether. “Sometimes skipping or postponing exercise is the safest option,” he states.
Sydney-based runner and exercise physiologist Veronika Larisova opts for early morning or late evening sessions to avoid peak heat. “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,” she shares.
“Extreme heat places additional stress on the cardiovascular system and thermoregulation, so maintaining the exact same intensity, duration, or timing year-round isn’t always appropriate or safe,” Larisova emphasizes.
The Benefits of Exercising in the Heat
Despite the risks, there can be benefits to exercising in warmer weather if done safely. Chalmers notes that regular exercise in the heat can lead to heat acclimation, a set of physiological adaptations that increase heat tolerance. “These include increased sweat rate, enhanced skin blood flow, greater body fluid volume, and a lower heart rate for the same exercise intensity,” he explains.
Fraser has experienced these benefits firsthand. “My wife, who is a running coach, always told me that running in the heat was the equivalent of doing altitude training,” he says. “Your mental strength improves, and after finishing a run in the heat, you get a huge endorphin fix.”
Exercising Safely in the Heat
To exercise safely in the heat, preparation is crucial. Jamie Crain, CEO of Sports Medicine Australia (SMA), advises drinking plenty of water before and during exercise, taking breaks, and wearing lightweight, breathable clothing. “Ensure you have access to shelter or shade and adjust your clothing as appropriate,” he suggests.
The Sports Heat Tool, developed by SMA and the University of Sydney’s Heat and Health Research Centre, can help assess heat-related risks for different sports. “Our tool integrates factors like internal heat production and clothing levels with local weather information to estimate heat stress risk for over 40 sports,” explains Professor Ollie Jay, Academic Director of the Heat and Health Research Centre.
Chalmers also recommends the tool, noting that different sports have varying risk profiles based on intensity and environment. “More intense exercise and activities with fewer breaks are typically riskier,” he says. “The heat risk tool can inform decisions about exercise intensity and cooling strategies.”
As temperatures continue to rise globally, understanding how to safely exercise in the heat becomes increasingly important. By taking appropriate precautions, athletes can continue to enjoy their routines while minimizing risks.
