Exercising During a Heatwave: How to Stay Safe, Perform Well and Recover Better
- angetooleypt
- 3 days ago
- 4 min read
When temperatures rise across the UK, many people find their usual workouts suddenly feel much harder.
The run that normally feels comfortable becomes a struggle.
The weights that usually move easily feel unusually heavy.
Even a brisk walk can leave you feeling more fatigued than expected.
If you've experienced this during a heatwave, it's not simply in your head.
Hot weather genuinely changes how your body responds to exercise.
The good news is that you don't need to stop exercising altogether when temperatures climb. However, understanding how heat affects the body—and adjusting your training accordingly—can help you stay safe, maintain consistency and avoid heat-related illness.
Why Does Exercise Feel Harder In Hot Weather?
When we exercise, the body produces heat.
In fact, only around 20–25% of the energy we generate during exercise is converted into movement. The rest becomes heat.
Normally, the body can dissipate this heat through:
Sweating
Increased blood flow to the skin
Evaporation
However, when the environment is already hot—or humid—these cooling mechanisms become less effective.
To prevent overheating, the body redirects more blood towards the skin to help release heat.
The downside is less blood is available for working muscles.
As a result:
Heart rate rises faster
Exercise feels harder
Fatigue occurs sooner
Recovery takes longer
This is why your usual pace may suddenly feel much more demanding during a heatwave.
Why Humidity Can Be Worse Than Heat
Many people focus on temperature alone.
However, humidity is often the bigger challenge.
Sweat cools us when it evaporates from the skin.
In humid conditions, sweat doesn't evaporate as efficiently.
Instead, it sits on the skin, making you feel sticky while providing less cooling benefit.
This means your core temperature rises more quickly and the cardiovascular strain of exercise increases significantly.
If you've ever felt completely drenched yet still overheated during a workout, humidity is usually the culprit.
Heat And Menopause: An Extra Challenge
For women navigating, hot weather can feel particularly uncomfortable.
Declining oestrogen affects the body's temperature regulation system, making many women more sensitive to changes in heat.
Common challenges include:
Increased hot flushes
Night sweats
Sleep disruption
Reduced tolerance to heat
Greater perceived exertion during exercise
When poor sleep from warm nights is combined with daytime heat, recovery can suffer.
This is often why workouts feel harder during summer months, even when fitness levels haven't changed.
Should You Stop Exercising During A Heatwave?
In most cases, no. Regular movement remains important for:
Cardiovascular health
Muscle maintenance
Blood sugar regulation
Mental wellbeing
Bone health
However, a heatwave may not be the time to chase personal bests.
Think of it as a period to maintain consistency rather than maximise performance.
Elite athletes regularly adjust training loads based on environmental conditions. Recreational exercisers should do the same.
Practical Tips For Exercising Safely In Hot Weather
1. Train Earlier Or Later
The simplest and most effective strategy is to avoid the hottest part of the day.
Aim to exercise:
Before 9am
After 7pm
Temperatures can be significantly lower during these windows.
If outdoor training is unavoidable, seek shaded routes wherever possible.
2. Adjust Your Expectations
One of the biggest mistakes people make is trying to maintain the same pace, weights or intensity they use in cooler weather.
Heat places additional stress on the body. This means:
Running pace may slow
Heart rate may be higher
Workouts may feel harder
This isn't a sign you're losing fitness, simply a normal physiological response.
Sometimes the smartest thing you can do is reduce intensity and focus on effort rather than performance metrics.
3. Prioritise Hydration
By the time you feel thirsty, you're already slightly dehydrated.
Hydration becomes increasingly important during hot weather because fluid losses through sweat rise significantly.
Practical strategies include:
Starting workouts well hydrated
Drinking regularly throughout the day
Including electrolytes during prolonged exercise
Monitoring urine colour as a simple hydration indicator
Remember that alcohol can worsen dehydration and impair recovery, particularly during hot weather.
4. Consider Shorter Sessions
Research consistently shows that shorter, more focused workouts can deliver significant health benefits.
During a heatwave, a 20–30 minute workout may be more productive than pushing through a longer session in uncomfortable conditions.
5. Strength Training May Be A Better Option
While endurance performance often declines in the heat, muscle function can actually benefit from warmer temperatures.
This doesn't mean attempting maximal lifts in a sweltering gym.
However, many people find:
Strength sessions
Mobility work
Pilates
Yoga
Circuit training
more manageable than prolonged endurance workouts during hot weather.
6. Don't Forget Recovery
Recovery becomes even more important when temperatures rise.
Focus on:
Adequate protein intake
Replacing lost fluids
Cooling strategies
Quality sleep
Warm overnight temperatures can disrupt sleep, which in turn affects recovery, appetite regulation and exercise performance.
If your sleep has suffered during a heatwave, it may be worth reducing training intensity temporarily.
Know The Warning Signs
Heat-related illness can develop surprisingly quickly. Stop exercising immediately if you experience:
Dizziness
Nausea
Headache
Confusion
Excessive weakness
Fainting
Chills or clammy skin
Unusual fatigue
Move to a cool environment, rehydrate and seek medical advice if symptoms persist.
Key Takeaways
Exercise remains one of the most powerful things you can do for your health, even during a heatwave. But hot weather changes the rules.
Rather than trying to train exactly as you would in cooler conditions, focus on adapting your approach:
Train at cooler times of day
Reduce intensity when needed
Stay hydrated
Prioritise recovery
Listen to your body's signals
Most importantly, remember that fitness isn't built from a single workout.
If the heat means slowing down, shortening a session or swapping a run for a walk, that's not a setback. It's simply smart training.
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