Caution urged over exercising outdoors as temperatures soar

Being well prepared and drinking plenty of fluids is important when running, cycling or playing sports

Some runners continue to hit the streets in late morning of afternoon even as temperatures hit 40C or more. Pawan Singh / The National

A man exercises outdoors at Sunset Beach in Dubai. Pawan Singh / The National

Doctors urge runners to drink 400-600 ml of water 30 minutes before exercise, and 100-200 ml of water every 10-15 minutes. Leslie Pableo for The National

Exercising at sunset is much safer - though it can be humid in the evenings. Satish Kumar / The National

A late night running club pictured at Zabeel Park. Jeffrey E Biteng / The National

The UAE’s warm weather is perfect for sun worshippers, but for residents keen to keep fit by exercising outdoors, it is not always ideal, especially during the summer.

In very hot weather, there can be risks associated with being too active, including of heat exhaustion, which can cause nausea, dizziness, increased sweating and a raised body temperature.

Even more serious is heat stroke, a potentially fatal condition in which the body becomes unable to control its own temperature. Often involving slurred speech, confusion and loss of consciousness, it requires emergency medical treatment.

But with a few precautions, it should be possible for most people to safely run, cycle or play sports outside, even during the hottest months of the year.

Exercising for several hours in a 40ºC environment without drinking can push the body to limits and the person has a high risk of heat exhaustion or heat stroke

Prof Gonzalez-Alonso

Here we speak to experts and outline strategies to ensure that outdoor summertime exercise remains low risk and enjoyable.

Prepare carefully

Before pulling on a pair of running shoes or setting off on a racing bike, it is worth checking with a medical practitioner, said Prof Stefan Schneider, a professor of neuroexercise at the German Sport University Cologne.

“The first thing to do, whether in a hot or cold country, is go to see your doctor,” he said.

“Everyone who wants to start exercising should see his or her doctor for a medical check-up, especially to check on the cardiovascular system if you’re exercising in the heat.

“Heat is an additional stress, probably especially on the cardiovascular system. Very often people underestimate the heat.”

People with medical conditions such as diabetes or heart disease should be particularly careful, as should children and older people, as their bodies may find it harder to regulate temperature. Anyone who has been ill should be cautious about getting back into exercise.

Experts say it is also a good idea to carry out a larger number of short exercise sessions, rather than a few long ones. Photo: Supplied

The right clothing is important. Lighter coloured garments reflect heat, as does a hat, while cotton may be less suitable than fabrics that wick sweat away from the body. Sunscreen is recommended if exercising in direct sunlight.

Some forms of exercise are better suited to hot environments. While running and cycling can be carried out safely in hot weather, swimming and yoga are sometimes seen as more heat-friendly.

Another issue is time of day: the late morning and the afternoon have the hottest weather, so are best avoided.

“It’s probably advisable to go for exercise in the [early] morning or evening,” said Prof Schneider. “Probably the morning is cooler than the evening. Everyone should avoid the heat peaks that come in the middle of the day.”

Drink plenty of water

It is important to gradually build up the amount of time that you spend exercising, said Prof Jose Gonzalez-Alonso, a professor of exercise and cardiovascular physiology at Brunel University in the UK.

So on your first day, it might be advisable to stop after about 30 minutes, but the day after five minutes can be added, and so on.

It is also a good idea to carry out a larger number of short exercise sessions, rather than a few long ones.

As water loss is a probable result of exercising in the heat, Prof Gonzalez-Alonso says that ensuring the body is well hydrated before starting is important.

“If you start already dehydrated, you will be more likely to stress the body. You want to prevent that,” he said.

Drinking about 250 to 300ml of fluid before a vigorous exercise session is sometimes advised, although it is not recommended to eat immediately before — or after — exercising.

During 30 minutes of exercise, a person may lose between half a litre and a litre of water and so it is recommended to drink this much afterwards to make up for what has been lost.

For an hour-long exercise session, a person should ensure they drink at least 200 to 300ml of water during the exercise itself, as this can ensure that weight loss is kept to within 1 per cent of their body weight.

Anything beyond this and it is advisable to drink a sports drink to help replenish electrolytes, the charged particles in cells and blood.

Don’t be put off

While exercising in hot weather does require precautions, Prof Schneider said that living in a hot climate should not put people off physical activity.

“I think the biggest risk is not to exercise at all; that really stresses the cardiovascular system. If you need to exercise and the climate is hot, take several precautions and go for it,” he said.

Prof Gonzalez-Alonso said that exercise in a hot environment may be particularly beneficial for the body, as long as precautions are taken to ensure it is safe.

“Exercising for several hours in a 40ºC environment without drinking can push the body to limits and the person has a high risk of heat exhaustion or heat stroke. But if you are well acclimatised and well hydrated, you can still maintain physiological function,” he said.

He said the fact that ultramarathons are held in extreme environments — a notable one is the Marathon des Sables, which covers 251km of the Sahara in southern Morocco — show that the human body can, with adequate precautions, deal with hot weather.

“When people prepare properly through heat acclimatisation and carry fluids and eat properly, they can do very well in hot environments,” he said.

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