Exercising on Those Warm Summer Days

It’s summertime! The days are longer, the sun is warmer, and we are feeling the heat! Every time I open my front door I get a blast of hot air that makes me want to turn around and go back inside my air conditioned house!

Even though the temperatures have been rising, I’ve still been wanting to get outside to exercise, as I’m sure many of you do too. As you head out in the blazing sun, there are a few things you need to keep in mind1.


Our bodies lose heat either through the evaporation of sweat or through the transfer of heat from our blood to the surrounding environment. In order for us to lose heat from our blood, the temperature of our environment needs to be less than the temperature of our skin.

More often than not, if you’re exercising on a warm summer day, your skin temperature is actually less than that of the environment around you. This makes it so your only avenue of heat loss is through the evaporation of your sweat. To maintain a safe temperature, your body will increase its sweat rate, which increases your risk of dehydration.


For those of us who get to enjoy high humidity in addition to rising temperatures, we have one more thing to worry about. High humidity decreases the ability of our body to cool down through sweating. There is already so much moisture in the air that our sweat can’t evaporate.

If you’ve ever been outside on a really hot, humid day you’ll remember that your sweat just pooled on your skin, making you feel clammy all over. Without any way for your body to cool itself down, you’re taking a big risk to exercise outside on a hot, humid day.


So what can we do? Well, you can always head inside to get your workout in. With the lovely invention of air conditioning we can exercise indoors on those really warm summer days and still stay cool. If you’re bound and determined to head outside, here are a few precautions you can take:


Head outside early in the morning, when the temperatures are lowest. Make sure you check the humidity levels before you leave and take a peek at the heat index chart below2. Avoid exercising outside when the heat index gets into the extreme caution levels and above. And be extra careful if you decide to head outside during the caution temperatures as well.


Dress appropriately. Clothing decreases the amount of heat you can lose. It insulates you and makes it harder for your sweat to evaporate. Tighter clothes in the heat will create less resistance to heat loss and won’t trap the warm air around your body. You can invest in clothes specially designed to wick the sweat away from your body, but it’s not necessary if you’re comfortable with what you already have. Avoid wearing dark colors that would absorb the sunlight and make you warmer.


Stay hydrated. Because you will be sweating more with an increase in outside temperatures, you will need to drink water more often than you normally do. Take water with you and drink when you’re thirsty. If you will be out for a while, take a few salty snacks to replenish the salts you’ll be sweating out and help stimulate your thirst. Make sure you start your exercise routine hydrated and continue to drink water throughout the day after your workout.


Acclimatize. The human body is amazing and can acclimatize to many different conditions. Individuals who have lived in very hot, humid environments their whole lives can function better outside in such an environment than individuals who are not used to it. Perform lighter intensity exercises outside for increasing amounts of time over a period of days to help your body get used to the high temperatures. Pay attention to your sweat rates, as they will increase as you become more used to the heat, and increase your water intake accordingly.


Most importantly – pay attention to what your body is telling you. If you are really dragging on a workout, if you start getting a headache, or if you feel sick in any way, stop exercising, move to a cool place, and get some water and food. Exercise with a partner so you can monitor each other and help if one individual becomes sick.


Don’t let the summer heat slow you down. You can still exercise outside as long as you pay attention to the weather, dress appropriately, stay hydrated, gradually work into exercising in the heat, and carefully watch for signs of heat illness. So get out and stay active this summer!




1. Cheung, S. (2010).Advanced environmental exercise physiology. Human Kinetics.

2. http://www.nws.noaa.gov/om/heat/heat_index.shtml