Exercising in the heat – a physician's perspective

With longer days and warmer weather, the summer months are the ideal time to take your fitness routine outside and enjoy it in fresh air and sunshine. While exercising in the heat, it is essential to remember that your health is at risk if you don't exercise with caution.

Physical activity beneficially stresses the body... However, increasing this stress by exercising in the heat or without adequate hydration places excessive pressure on our bodies' defence mechanisms, resulting in heat exhaustion or heatstroke in the worst-case scenario.

How do our bodies react when we exercise in warmer temperatures?

When you exercise, your body's demand for oxygen increases, causing you to breathe more quickly and your heart to pump more blood around your body to help your muscles work more efficiently. As a result, you generate more heat, which causes your core temperature to increase.

We dilate our blood vessels (thereby increasing the surface area for heat loss) and sweat to regulate our core temperature. The heat that is removed from your body by your sweat is lost. When we are out in the sun or a hot environment, our bodies are forced to do even more of this, primarily through increased sweating.

How can I safely exercise in the heat?

When exercising in hot weather, there are some simple precautions you can take to keep yourself safe:

Consume water with extra vigilance.

When exercising in the heat, it's critical always to stay hydrated. When you exercise, you should drink plenty of fluids to replace the fluids you lose through sweat. If you're exercising for an extended period and sweating heavily, you should also drink sports or electrolyte drinks to replenish the salt you've lost through sweating.

Use sunscreen to protect your skin.

It is critical to wear sunscreen during your outdoor workouts to keep your skin protected. Sunburn not only increases your risk of developing skin cancer, but it can also impair your body's ability to cool itself. Apply a generous amount of high-factor SPF sunscreen 20 to 30 minutes before engaging in strenuous physical activity in the heat. Make sure to choose a sunscreen that offers UVA and UVB protection when purchasing.

Exercise at the appropriate time.

Try to exercise first thing in the morning or later in the evening if it's scorching outside to avoid the heat and humidity of the midday sun. If possible, exercise in shady areas and allow adequate rest, hydration, and cooling afterwards.

Choose an appropriate kit to keep you cool and dry.

Choose breathable clothes, light in colour and easy to move around in. These will allow sweat to evaporate and cool down more quickly. If your clothes are too heavy or tight, your body cannot cool itself down as effectively.

Allow your body to adjust to the heat.

Heat and humidity will impact your workout, so paying attention to your body's signals is essential. It may take several weeks for your body to acclimate to the heat, so begin with shorter, less intense workouts. As you become more accustomed to the heat, you may notice that your body responds more positively to it. For example, your body may begin sweating earlier to help you cool down, and your heart rate may not rise as high during your workouts as it did initially.

It's essential to take it easy in the sun and not push yourself beyond your capabilities.

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