What Athletes Need to Know About Heat Illness

UK Fitness Pro
UK Fitness Pro
· 3 min read
An athlete experiencing heat illness

When you work out in climbing temperatures, you may be more likely to suffer from conditions like dehydration, heat stroke, and heat exhaustion. 

Fortunately, most heat-related illnesses can be prevented with proper planning and preparation. 


Dehydration occurs when your body loses more water than it takes in. This is more likely to occur during warm days when you lose water through sweat. According to the NHS, early signs of dehydration include: 

  • Feeling thirsty
  • Dark yellow, strong-smelling pee
  • Dizziness
  • Feeling tired during the day

If you suspect that you have become dehydrated, stop exercising and move to a cool, relaxing space. Slowly drink fluids to increase your hydration steadily. It’s easy to become over-hydrated in response to dehydration. Instead, focus on finishing your current cup and monitor your body closely until you become adequately hydrated. 

Heat Stroke and Exhaustion

Heat stroke happens when your body is unable to cool itself and regulate temperature effectively due to heat. Usually, heat stroke happens during the warmest part of the day when you are exposed to the sun and are exercising vigorously. Common signs of heatstroke include: 

  • Tiredness
  • Confusion
  • Feeling sick
  • Cramps
  • Excessive sweating

You’re more likely to suffer from heatstroke if you are dehydrated or are drinking alcohol. Even if you’re well hydrated, you may need to modify your workout to avoid warm temperatures and minimise your risk of heat illness. 

Modifying Your Workout

Even if you’re in peak physical condition, heat illness can be a serious issue. 

Start by rescheduling your exercise regime. For example, if you’re a runner, try to plan your runs during the early hours or around dusk. This will keep you out of the warmest temperatures and reduce your risk of heat illness. 

If you can’t change the timing of your workout, consider training at home. There are plenty of Pilates or HIIT workouts available online. Light dumbbells and resistance bands are usually relatively cheap, too, so you won’t have to drop a bomb on a complete home gym

If you want to work out from home, make sure you know how to regulate the temperature in your house. Most houses in the UK don’t have AC, so you should get creative with shady landscaping that can prevent harsh sunlight from entering your home. You may even want to work out with the curtains drawn, as your living room can quickly become a sauna when you start to sweat. 

If you’re playing a sport, take a leaf out of the Premier League’s book and include more frequent water breaks. Increasing the amount of fluid you take onboard can prevent dehydration and act as a shield against conditions like heat stroke. 

If You Become Unwell

Stop your workout immediately if you start to feel ill. 

There’s no point pushing through a workout when you are suffering from heatstroke, as falling ill will just set your fitness goals back. 

Most heat-related conditions don’t require emergency medical attention. Googling your symptoms and sticking to reputable sources like the NHS website can help you start to get heat illness under control. Dr. Google isn’t a replacement for real medical attention, but it can help you get heat illness under control. 

If you’re still suffering from your illness after Googling your symptoms, getting out of the heat, and rehydrating, you may need to call your doctor to seek further medical attention. 

Once you’ve recovered, consider what went wrong and how you can better modify your workout to prevent future heat illnesses. Even small changes, like packing an extra water bottle, can make a big difference to your performance and help prevent heat-related illnesses. 


Heat illness can be a serious condition that you shouldn’t ignore. Learn to read the early signs of dehydration and ensure you always have enough water before you start working out. 

Consider switching up your workout routine to dawn or dusk if you are worried about high temperatures. If there’s no way around exercising during the day, try to work out in shaded areas and add as many water breaks as needed to maintain adequate hydration. 

If you do start to suffer from heat-related illness, stop exercising and find a cool place to drink water and relax. Always speak to a doctor if your symptoms don’t get better after rest and rehydration.