Exercising in the heat – a doctor’s guide

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Dr Samuel Menon, Lead GP at Livi, shares his tips on how to exercise safely as temperatures rise

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With longer days and warmer weather, the summer months are the perfect time to take your fitness routine out into the open air. But if you don’t take care when exercising in the heat, you may be putting your health at risk.

‘Exercise stresses the body in a beneficial way,’ says Dr Menon. ‘But aggravating this stress by exercising in the heat, or without proper hydration, puts excessive pressure on our body’s defence mechanisms and can result in heat exhaustion – or worse, heatstroke.’

What happens to our bodies when we exercise in warmer temperatures?

When you exercise, your demand for oxygen increases – you breathe faster and your heart pumps more blood around your body to aid your muscles. As a result, you produce more heat and your core temperature rises.

‘To regulate our core temperature, we dilate our blood vessels (creating a greater surface area for heat loss) and we sweat,’ explains Dr Menon. ‘As your sweat evaporates, it takes heat with it. If we’re in the sun or in a hot environment, our bodies have to do even more of this, mainly by sweating more.’

How can I exercise safely in the heat?

Here are some simple ways to stay safe while you’re exercising in hot weather:

1. Be extra diligent about drinking water

Staying hydrated is really important when exercising in the heat. As you work out, you need to drink fluids to replenish what you’ve lost in sweat. ‘If you’re exercising for prolonged periods and sweating a lot, you should also replace the salt you’ve lost by drinking a sports or electrolytes drink,’ recommends Dr Menon.

2. Protect your skin with SPF

Dr Menon says that it’s important to wear sunscreen during your outdoor workouts to protect your skin. Sunburn not only increases your skin cancer risk, but it can also affect your body’s ability to cool down. Apply a high-factor SPF sunscreen liberally 20 to 30 minutes before exercising in the heat. Make sure you choose a sunscreen that has both UVA and UVB protection.

3. Work out at the right time

When it’s really hot, try exercising in the morning or later in the evening to avoid the heat and humidity of midday. If possible, exercise in shady areas and take time to rest, hydrate and cool down.

4. Choose kit that will keep you cool and dry

Opt for clothes that are breathable, light-coloured and lightweight. ‘These will allow sweat to evaporate, so you can cool down,’ explains Dr Menon. ‘If clothes are heavy or tight-fitting, your body is unable to cool down as effectively.’

5. Let your body get acclimatised to the heat

The heat and humidity will affect your workout, so it’s important to listen to your body. It may take a few weeks for your body to acclimatise to the heat, so start slowly with shorter and less intense workouts. As you get used to the heat, you may find yourself responding better to it – your body may start sweating earlier to help you cool down, and over time, your heart rate may not rise quite as high during your workouts.

‘Take it easier in the sun so you don’t push yourself beyond your limits,’ says Dr Menon.

This article has been medically approved by Dr Samuel Menon, Lead GP at Livi.

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