As heatwaves become more frequent, many people are finding it increasingly difficult to maintain their usual fitness routines. Researchers have even warned that rising temperatures could contribute to lower physical activity levels worldwide, potentially increasing long-term health risks.
The good news is that with a few simple adjustments, you can continue exercising safely even when temperatures climb.
Why exercise feels harder in the heat
Whenever you exercise, your muscles generate heat. To prevent overheating, your body redirects blood towards the skin and produces sweat.
That cooling process comes at a cost.
According to Professor Ollie Jay, director of the Heat and Health Research Centre at the University of Sydney, the same blood needed to cool the body is also needed to deliver oxygen to working muscles.
As a result, muscles receive less oxygen, fatigue sets in earlier and the heart must work harder to meet the body's demands.
The combination can make even routine exercise feel significantly more strenuous than usual.
Exercise at cooler times of day
One of the most effective strategies is simply to avoid exercising during peak heat.
Experts recommend scheduling workouts in the early morning or later in the evening, when temperatures are lower.
Shade can also make a significant difference. According to Jay, temperatures in direct sunlight can be 12-15°C higher than the surrounding shaded air.
If possible, choose tree-lined routes, covered areas or parks with plenty of shade.
Don't ignore humidity
Temperature is only part of the story.
High humidity makes it harder for sweat to evaporate, reducing the body's natural cooling mechanism.
When the air is already saturated with moisture, sweat remains on the skin instead of evaporating efficiently, meaning body temperature rises more quickly.
Poor airflow can make matters worse, which is why exercising indoors without ventilation can sometimes feel hotter than being outdoors.
Reduce intensity and duration
When conditions are particularly hot, sticking rigidly to your normal training plan may not be the smartest option.
Instead, consider:
- Shorter workouts
- More frequent breaks
- Slower running or cycling speeds
- Lower-intensity activities such as walking
Environmental lifestyle epidemiologist Christian García-Witulski says that adapting routines to the conditions is often safer than trying to maintain normal performance levels.
A shorter workout completed safely is preferable to pushing through dangerous heat stress.
Take cooling breaks
Rest periods are most effective when they allow the body to genuinely cool down.
Whenever possible, move into:
- Air-conditioned spaces
- Shade
- Areas with fans or airflow
Cold drinks, water sprays and shaded recovery periods can help reduce thermal strain before resuming activity.
Cool your body efficiently
Reaching for an ice pack may feel instinctive, but experts say there are often more effective cooling methods.
One of the best approaches is cold-water immersion, particularly of the hands and forearms.
Pouring water over the skin can also be highly effective.
As the water evaporates, it removes heat from the body in much the same way sweat does, helping lower body temperature while reducing the need for excessive sweating.
A cold, wet towel applied repeatedly to the arms, legs and torso can provide similar benefits.
Pre-cool before you start
Research suggests it may help to cool your body before exercise even begins.
This can include:
- Taking a cool shower
- Spending time in an air-conditioned environment
- Drinking icy water or ice slurries
Lowering body temperature beforehand gives you a larger safety margin before heat stress becomes dangerous.
Allow your body to adapt
Regular exposure to hot conditions can trigger a process known as heat acclimatisation.
After around one to two weeks of gradually exercising in the heat, the body typically becomes more efficient at managing high temperatures.
Adaptations may include:
- Lower resting body temperature
- Increased sweating efficiency
- Expanded blood plasma volume
- Improved cardiovascular performance
These changes can improve both comfort and safety.
However, the adaptations are temporary and fade if heat exposure stops.
Know when to stop
Even experienced athletes are not immune to heat illness.
In fact, elite competitors can sometimes be at greater risk because they are accustomed to pushing themselves beyond normal limits.
Warning signs that exercise should stop immediately include:
- Dizziness
- Nausea
- Extreme fatigue
- Headache
- Heart palpitations
- Confusion
- Loss of coordination
If any of these symptoms occur, stop exercising, move to a cool location and begin cooling down straight away.
The bottom line
The safest heatwave exercise strategy is straightforward:
- Train early or late in the day
- Seek shade whenever possible
- Consider humidity, not just temperature
- Lower your intensity
- Take more breaks
- Use water to cool your body
- Gradually adapt to hot conditions
- Stop immediately if symptoms of heat illness appear
As heatwaves become more common, experts say exercise routines will increasingly need to adapt to the climate. The key is not to stop moving altogether, but to exercise smarter when temperatures soar.
Source: BBC
