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As the recent heatwave brought widespread sunny weather, potentially beating temperatures seen in June, we sat down with The Institute of Sport, Exercise and Health's (ISEH) Professor Courtney Kipps, Consultant Physician in Sport and Exercise Medicine at UCLH and co-lead of UCL’s MSc programme in Sports Medicine, Exercise & Health. Professor Kipps shares helpful advice and tips surrounding exercising in warm weather, the effects of heat on the body and insight about water consumption.

How does heat/hot weather affect your body, both positively and negatively?

Hot weather can have both positive and negative effects on the body. Positively, exposure to heat can increase blood flow, promote sweating, and improve cardiovascular function. It may also boost mood and provide an opportunity for outdoor activities, benefiting mental health.

On the other hand, prolonged exposure to hot weather can cause issues if you don’t have access to shade or fluids.  Without adequate fluid replacement you can become dehydrated, and overexertion in hot and humid temperatures can lead to exertional heatstroke. In people with existing health conditions, high temperatures and dehydration can overload the cardiovascular system, and potentially worsen those underlying health conditions.

Prolonged exposure to heat at night may also disrupt sleep patterns, affecting overall well-being.

How to stay cool while exercising in hot weather (dry and humid)?

Exercising in hot weather, requires extra attention to ensure your safety and well-being. The following tips will help you stay cool and comfortable during your workouts:

Hydration: One of the most crucial factors is hydration. If you’re planning a long exercise session, make sure to keep hydrated by drinking water before, during, and after your exercise session.

•    Dehydration can affect your performance on skills-based tasks (although it is unlikely to present a significant problem during short exercise sessions of less than an hour or two.)
•    Listen to your body, and drink as much as your thirst tells you to drink. Contrary to old-fashioned advice, thirst is in fact an extremely effective warning mechanism.

Choosing appropriate clothing is essential: Opt for light-coloured, loose-fitting, and moisture-wicking clothes. Sweat is your body’s best form of heat loss and these clothing choices allow better air circulation enabling sweat to evaporate, and helping to keep your body cooler.

Timing your workouts is vital: Try to exercise during the cooler parts of the day, such as early mornings or late evenings to avoid the peak heat hours, typically from 10 am to 4 pm.

Hot and humid weather: Try not to push yourself too hard if it’s hot and humid. When it is humid your sweat won’t evaporate as effectively so your body will retain more heat. Take regular breaks during your workout to rest and cool down. Utilise this time to find shade and rehydrate yourself.

Cooling accessories: Using cooling accessories can provide additional relief; consider carrying cooling towels, neck wraps, or handheld fans to help cool your body during exercise. Cold drinks or ice slurries and slushies are very effective too.

Don't forget sun protection: Apply sweat-resistant sunscreen to shield your skin from harmful UV rays. Sunburn not only hurts but also hampers your body's ability to regulate temperature.

Listen to your body's signals: Pay attention to signs of dizziness, nausea, or excessive fatigue. If you experience any of these symptoms, stop exercising immediately, find a shaded area to cool down and rehydrate if necessary.

Exercise indoors: On days when the heat is too intense, consider indoor workout alternatives like using a treadmill, indoor cycling, or joining a fitness class in an air-conditioned gym.

The importance of water

Water becomes even more important when exercising in hot weather. When you exercise in high temperatures, your body temperature rises, and you sweat to cool down. Sweating is the body's natural way of regulating temperature, but it also leads to fluid loss. Therefore, staying hydrated during exercise in hot weather is crucial for regulating body temperature and maintaining performance. Listen to your body and drink when you’re thirsty. 
How to spot when you're overdoing in/ the signs of heatstroke

While exercising in the heat, be vigilant about signs of overdoing it or heatstroke. Keep an eye out for feelings of unexpected weakness, dizziness, or excessive fatigue.  Nausea, vomiting, headaches, suggest that you may be overloading yourself. In extreme cases, confusion, or fainting may occur. If you experience any of these symptoms during exercise in the heat, it's vital to stop immediately, call for help and recover in a cool shaded area.

Best exercises to do in hot weather

If you are not used to exercising in hot weather, the best exercises to do are those that are shorter duration or lower intensity, which are less likely to cause overheating. Exercises that are well-suited for hot weather are:
•    Swimming
•    Walking
•    Pilates 
•    Tai chi

Through ISEH’s partnership with UCLH, Professor Courtney Kipps sees and manages patients at The ISEH for a host of sports related injuries and complaints.
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