Centr trainer Alexz Parvi pauses to rest during a workout on a hot day.
Centr Team

Training in the heat: your survival guide

Centr Team

A year of record-breaking temperatures across the globe is not ideal when you’re aiming for a personal record on the workout mat.

But as climate change causes extreme heatwaves to become more frequent, and warmer-than-usual weather seems to extend summer at both ends, are we just going to give up exercise for 6 months of the year?

Of course not – but we do need to adapt to stay safe while training in the heat.

How hot is too hot to exercise?

There’s no single rule for how hot is too hot to work out.

In January 2023, play at the Australian Open tennis was suspended when temperatures hit 97ºF (36ºC), while in October, the annual Twin Cities Marathon in Minneapolis was called off when the forecast predicted an unseasonably hot 91ºF (33ºC) day.

Most of us don’t have a big sporting organization to make the call for us, so your personal ability to stay safe in the heat will depend on many things:

  • How well you have slept

  • If you have been drinking alcohol

  • Your current fitness level and whether you’re used to exercising in the heat

  • Whether you take any prescription or over-the-counter medications that can cause heat intolerance

  • Chronic or short-term illnesses which can impact your body’s ability to regulate temperature

  • Your age (people over 65 have less tolerance for extreme temperatures)

Ultimately, determining when it’s too hot to exercise for YOU is about listening to your body. We’ll give you some of the signs to look out for below.

Centr trainers Sylvia Roberts and Tahl Rinsky perform a leg lift as part of a Pilates workout.

When the heat is on, consider a slower paced Pilates session to bring the burn with less sweat factor.

How to handle the heat

If you don’t want to put your goals on pause until winter, or stop getting your sweat on in the great outdoors, try these tips to stay cool while still smashing it.

Work your way up. If you’re heading into summer and you’re not sure how your body will endure the heat, it’s a good idea to acclimatize by building up your training intensity and duration over a couple of weeks.

Move your workout away from the hottest part of the day. When the heat is on, aim to train before 9am or after 6pm. But we know “getting up early to beat the heat” can’t always be done, so…

Try a different form of exercise. If your regular HIIT session in the park is just too darn hot, try mixing it up by swimming or hitting play on a yoga session.

Pick a different venue or route. Pull up a workout on the Centr app in the comfort of your aircon (or the gym’s). Find a spot in the shade or with a breeze. Get it done on the grass rather than concrete or asphalt (which retains heat). If you’re running, can you find a shadier route to take?

Wear the right gear. As Luke explains, “sweat is there to control your body temperature – when you start heating up, sweat cools your body as it evaporates from your skin”. So it may be time to retire your favorite old cotton workout tee, as it will just trap all that sweat. Opt for loose-fitting clothes made of synthetic materials (for example, polyester or rayon blends) that wick sweat away from your skin. And reach for a lighter color, as black absorbs the heat from the sun.

Don’t forget the sunscreen. Sunburn decreases your body’s ability to cool itself, so put that SPF lotion on before you head out (and reapply if you’re sweating through a long one).

Check the humidity. Training in humidity can be very different from training in dry heat, as the moisture in the air slows the evaporation of sweat and blocks your body’s natural cooling system. So download a weather app and keep an eye on that humidity percentage.

Listen to your body and take regular breaks. Head into the shade in your rest breaks and have a drink. During an extended period of hot weather, it may be a good idea to train every second day rather than daily – this will give your body a chance to recover.

Hydrate. Hydrate. Hydrate. Before, during and after your training. We’ll take a deep, refreshing dive on this below.

Centr trainer and chef Dan Churchill takes a big sip of water after a workout in the heat.

Follow Dan’s lead on warmer days.

Know the signs of heat stress

Our bodies are designed to run at a steady 98.6°F (37°C). This temperature rises when we’re exercising in hot weather, and if we can’t get rid of this extra heat, it can lead to heat-related illness known as heat stress or heat exhaustion.

If this stress is not treated, it can lead to heat stroke – shutting down many of the body’s basic processes.

Signs of heat stress to look out for include:

  • headache

  • dizziness

  • muscle cramps

  • nausea or vomiting

  • weakness

  • loss of coordination

  • unusually rapid heartbeat

As well as following the tips above to stay safe in the heat, work out with a friend where possible so you can look out for each other.

Hydration station

This last tip is so important, we thought we’d better take a deep dive.

When you exercise in the heat, the fluids you lose through sweat can often exceed water and electrolyte intake. As an experienced marathon runner, Centr expert Dan Churchill knows it only takes a 2 percent decrease in hydration for your performance to drop. As we talked about above, dehydration can also lead to heat stress.

So how much should you be drinking when the temperature spikes? Our resident sports dietitian Angie Asche recommends a minimum of 1/2 cup of water for every 15 minutes of training – that’s on top of your normal water intake.

“You may be falling short if you’re not also replenishing electrolytes (aka essential minerals) like potassium, magnesium, and sodium,” she adds.

Angie recommends replenishing electrolytes after training in the heat for one hour. While the most common way to do that these days is reaching for a bottled sports drink, you can also DIY it like Angie.

A glass of Watermelon Sports Drink, from the Centr meal library, sits on a table.

After a hot sweat sesh, replenish your electrolytes by whipping up Angie’s Watermelon Sports Drink in 5 minutes flat.

Next time you’re busting out your best moves as the temperature soars, take these tips with you to stay cool – and stay safe.

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