The 2021 Tokyo Summer Olympics are predicted to be the hottest games on record and athletes will be facing unprecedented challenges for staying cool while performing at their best. To help these competitors stay safe while participating, the world’s best exercise scientists have compiled recommendations on best practices for physically exerting in hot weather. The good news is the techniques can be just as effective for everyday athletes and exercisers. Read on for the best ways to stay cool and perform at your best while exercising outdoors in the heat.

Adjust Your Workout and Expectations

Exercising in any weather causes the body to generate heat, which it then dissipates through blood circulation to the skin and sweat. Hot weather can impede this process, making it harder for the body to dissipate heat, further taxing the heart and making workouts feel much harder. An exercise routine that feels doable on a mild day can feel like an epic challenge as temperatures begin to rise. When first being active in hot temperatures, experts recommend making workouts shorter and less intense. Another option is to begin working out outside and then finish indoors, where your body will be able to cool itself more easily. 

Adjusting your expectations is just as important as adjusting your physical workout. Workouts will feel harder and slower when temperatures rise. It is never a good idea to try and set a personal record or do super challenging workouts when the temperatures are higher than normal. On hotter days, hoping to enjoy some time outside and a decent workout is a better goal.


Acclimation is the process of your body adjusting to exercising in hotter temperatures. Experts recommend doing shorter, milder versions of your regular workouts during increasingly hot temperatures to facilitate this process. Acclimation usually takes about 5 to 10 workouts, though it can take a bit longer for women, who tend to sweat less. You will know your body is acclimating when you begin to sweat sooner and more as you begin your routine.

A heart rate monitor is another way to monitor your effort level and the acclimation process. When you first begin exercising in the heat your heart rate will be higher to maintain your usual pace/effort. As you acclimate, your heart rate will begin to drop even as you accomplish the same amount of work.


At the Tokyo Olympics the marathon event is slated to begin at dawn, when the daily temperatures are still moderate and the cumulative effect of the day’s heat has not begun to build. Planning your outside activities to be during the cooler parts of the day is one of the most effective ways of navigating intense summer temperatures. In most places, early morning exercise is the ideal choice. If this isn’t possible, early evenings can also be more moderate. For the best information check hourly forecasts and plan your outdoor exercise around predicted temperatures.


There are several ways to vary your location choice to minimize the impacts of hot weather. Natural settings with more grass, greenery and unpaved surfaces will always be cooler than streets and sidewalks.  For endurance activities like running, walking and cycling, choosing shorter loops can make it easier to get to water stops and to a cool place if you begin to feel the heat’s impacts. The safest place to exercise when it is very hot outside is indoors.

Buddy up and have a plan

When exercising during hot summer months, it’s important to know the signs of overheating which include nausea, dizziness, headache and muscle cramping. If any of these symptoms are felt, experts recommend stopping the activity immediately, finding shade and taking cooling measures such as drinking cold water or placing a cooling cloth on the back of your neck.

Heat illness can also impede thinking, which is why the buddy system is also a good idea. 

A training partner can notice if you are showing signs of cognitive dysfunction—as you can do for them as well—helping to protect both of you from potential problems. Having a plan for what to do if you experience symptoms of overheating is also important. This could include knowing where to find shade, having a friend to call or storing cool water along your route.


Hydrating is even more important when exercising in hotter temperatures because the body loses more water through sweating. Signs of dehydration include dark colored urine, thirst, weakness, fatigue, dry mouth and headache. For most people, drinking 16 oz of cool liquid 20 to 30 minutes before a workout will help with topping off hydration reserves and reducing risks of overheating. Consider using a cooler or insulated container to keep your water cool during a workout and stashing multiple hydration options along your route. Splashing water on hats, hair, and not chafing gear is another way to stay cool.

How do you stay cool with the temperatures spiking?