With more sunshine hours, many of us will opt to skip the treadmill and stationary bike in the gyms and head outdoors for a jog or bike ride instead. But exercising outdoors means hotter temperatures which can become challenging with an increased risk of dehydration, heat exhaustion or, worse, heat stroke. Heat stroke is when the body can no longer regulate its temperature and it keeps rising1.
When we exercise, our body’s temperature increases, even if we’ve only done a few minutes of cardio. The heat occurs as your muscles use up stored energy while creating more energy to keep you moving. As your body gets hotter, it works to regulate its temperature and cool down through vasodilation (the dilatation of blood vessels which decreases blood pressure), sweating, and heavier breathing. A variety of factors affect how high your body temperature can get such as the type of activity, fitness level (particularly aerobic) and climate/room temperature2.
So, if you’re ditching the gym to workout in the sun, here are some tips to help you exercise safely during the warmer summer days.
1. Keep the fluids up
As a rule of thumb, staying hydrated throughout the day is important for overall health and wellbeing. But as you move more during exercise, your body will work more to regulate its temperature by sending a message to the hypothalamus in the brain to stimulate the sweat glands in your skin. This results in heat being removed as the sweat evaporates from your skin3.
But as you sweat, your body loses fluids. The longer and more intense the workout, the more fluids are lost. On warmer days, your body temperature may already be raised, leading to even more fluid loss and increasing your risk of dehydration. Dehydration occurs when the fluids lost through sweating aren’t replaced and can lead to headaches, muscle cramps, and nausea4. Even if you aren’t feeling thirsty, drink plenty of fluids before, during, and after your workout.
2. Go light on the food
If it’s already hot outside, your body will already be feeling the heat. If you add in a hearty meal before you exercise, your body will be generating even more heat as it uses blood and energy as part of digestion. If you need to fuel your workout, consider a light snack or meal5. It’s recommended to leave at least an hour between your workout and eating, particularly on hotter days.
3. Protect your skin
Your skin is the largest organ in your body and the ultimate tool to regulating your body’s temperature. Its large surface area and immense network of blood vessels allows for heat loss by expanding the size of blood vessel to increase blood flow (vasodilation). With blood flow closer to the surface, heat can be transferred when cool air or water passes over your skin6.
If your skin becomes damaged, it may not be able to properly regulate your body’s temperature. Make sure to lather the sunscreen on during summer to protect from skin damage, and consider wearing loose, light-weight clothing that blocks the sun – this includes a hat!
If you’re exercising, consider sweat-wicking clothing that allows your skin to breathe during hotter days. Exposing your skin can be helpful in allowing sweat to evaporate and cool you down but remember to apply sunscreen regularly as the UV rays will be out in force7.
4. Switch it up
Another way to keep your body temperature at a reasonable level is to head out earlier in the day or later in the evening. The cooler air will support your skin’s efforts to regulate your body’s temperature and aid in reducing fluid loss through sweat. If you are set on a lunchtime run, find a shaded route or a route with some shaded areas to cool down in. This will help to avoid heat exhaustion and heat stroke.
Also consider different ways to get active like instead of a run, try swimming. The water will help keep you cool. If you’re want to bike, find a shaded mountain bike track instead of the open road where you’re likely to spend more time in the sun.
5. Listen to your body
When you exercise, it’s important to remember that you are putting your body to work – your heart is pumping, your lungs are breathing, skin is sweating, and your muscles are working overtime. Different areas of your body are competing for blood and energy, so it’s okay to slow down and ease up on the intensity of your workout. This is important if you have heart issues, are diabetic, or if you are not regularly active.
Listen to your body and adapt your workout to avoid dehydration and heat stroke. Small light workouts split across a hot day can be much more beneficial and cooler, than overheating the body with an intense session under the summer sun.
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Footnotes:
- https://www.livestrong.com/article/361702-why-does-body-temperature-increase-during-exercise/
- https://www.livestrong.com/article/361702-why-does-body-temperature-increase-during-exercise/#:~:text=Does%20Exercise%20Increase%20Body%20Temperature%3F
- https://health.howstuffworks.com/wellness/diet-fitness/exercise/sports-physiology11.htm
- https://www.stjohn.org.nz/First-Aid/First-Aid-Library/Immediate-First-Aid1/Environmental-Conditions/#:~:text=2.%20Heat%2Drelated%20conditions
- https://www.healthline.com/nutrition/how-much-time-between-eating-and-working-out#1
- https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Anatomy_and_Physiology_(Boundless)/5%3A_Integumentary_System/5.4%3A_Functions_of_the_Integumentary_System/5.4B%3A_Thermoregulation
- https://www.npr.org/sections/health-shots/2021/07/19/1016989389/how-to-heat-proof-your-summer-workout#:~:text=Wear%20material%20that%20will%20help%20your%20body%20breathe/