Strategies to Beat the Heat

July 10, 2023 – Defence Stories

Question: I exercise outside year-round but during the summer months I find the hot and humid weather very challenging. This is becoming worse as I age. I sweat a lot when I’m physically active, and this is especially pronounced in warm environments. My best friend recently experienced heat exhaustion during a run and I was hoping you could provide some advice on how to reduce the risk of this happening to me. Sweaty Betty.

Answer: Dear Sweaty Betty, It is wonderful to hear you are an outdoor exerciser. It’s not uncommon for people to find exercising in hot weather stressful and this increases their risk of experiencing heat-related injuries. Unfortunately, with global warming, this is likely to get worse.

It is important to recognize the body is not a very efficient machine when it comes to exercising. Seventy-five per cent of the energy used by working muscle is lost to heat production and while this is handy in the winter, it can be a big problem in hot weather.  The body uses several mechanisms to dispose of heat and sweating is one of them.  Unfortunately, these mechanisms can be overwhelmed when you exert yourself in hot weather, especially if you are not acclimatized.  When this happens, your body temperature will start to rise, and you can quickly get into trouble. The following are some strategies you can use to better cope with exercising in the heat:

1. Check the weather report before you head out and don’t just focus on the temperature.  You also need to be aware of the humidity and the UV index – both can make exercising in the heat more dangerous.

2. Ensure you are acclimatized – acclimatization is the body’s way of becoming more efficient at handling heat stress and it takes several weeks of exercising in the heat to achieve, not several hours.

3. Pull back on the throttle – you are smart to reduce the intensity of your training in hot weather, especially if you are not acclimatized.

4. Avoid sunburn as this not only increases your risk of future skin cancer, but sunburned skin is less effective at sweating – one of the most important heat dissipating mechanisms the body has.

5. Don’t train in the heat of the day – training in the early morning or when the sun goes down will be much more comfortable.

6. Clothing is important – don’t overdress and try wearing light coloured clothing that is made with breathable materials.

7. Seek the shade – running, biking, or walking on forest trails often provides a significantly cooler environment than doing these activities on hot pavement.

8. Avoid exercising in the heat if you are ill.  When your body is already fighting a bug, having to also fight the heat could be overwhelming.

9. Hydration is extremely important – be sure to drink fluids before, during and after your training. What you drink is also important. Energy drinks and alcohol are dehydrators and should be avoided. If your workout lasts for less than an hour you can hydrate effectively with water. If your workouts are longer than this, then you should hydrate with one of the commercially available electrolyte products.

10. Finally, on days when the heat and humidity are extremely high – you should consider doing your workout in an air-conditioned environment, going for a swim, or taking a day of rest.

You can find more information at this website: CCOHS: Hot Environments – Health Effects and First Aid.

Bottom line: Exercising in hot and humid weather can subject the body to considerable stress, especially if you are not fully acclimatized. Your body does have mechanisms it can use to prevent your body temperatures from rising but these mechanisms have their limits. Using the above strategies to help you “Beat the Heat” will not only make your summer safer, but will also help you have more fun. Exercise truly is medicine, even in the heat!

Dr. Darrell Menard OMM MD, Dip Sport Med

Dr. Menard is the Surgeon General’s specialist advisor in sports medicine and has worked extensively with athletes from multiple sports.  As part of the Strengthening the Forces team, he works on injury prevention and promoting active living.

Strengthening the Forces is CAF/DND’s health promotion program providing expert information, skills, and tools for promoting and improving CAF members’ health and well-being.