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by Danielle Clark-Fox, DPT


running high temperatureWelcome to mid-summer in New England! When the temperature is up, humidity is off the charts and I’m trying to keep my running schedule going, I won’t feel bad about the ice cream in my freezer disappearing after dinner! Turns out, I’m not the only one trying to find the best way to enjoy the weather- quite a few patients are asking for advice as well. So, here are some tips I have researched to help us all enjoy our short summer and keep our training schedules in check.

Rule number one (not a tip, but a rule) please check the heat index before you exercise! This number factors in the humidity to tell us what the heat really feels like to our bodies. When the humidity increases our bodies don’t evaporate sweat off our skin as well- and this is your body’s number one cooling mechanism. Check the National Weather Service website for the daily heat index near you.

Based on what the heat index is, here are some exercise recommendations:

  • 79 degrees or lower: a great day for a long run or hill workout, high intensity
  • 80-90 degrees: keep workout shorter and moderate intensity only
  • 91-103 degrees: try to exercise early in the morning and light intensity only
  • Greater than 104: move your workout indoors or take a rest day

Tip number 1: please try to exercise morning or evening (except for a day when heat index is 91-103 and you want morning) when your shadow is taller than you. Basically this means you don’t want to be running in direct sunlight hours which can increase how hot your body thinks it is by 15 degrees!

Tip number 2: please mind the 90 degree line, even if the heat index isn’t that high. When it’s 90 degrees outside, or hotter, you will actually gain heat from the environment and the heat you generate exercising won’t have anywhere to go. This raises your body temperature and increases the risk of heat related issues (heatstroke, headache, dizziness, and blood pressure issues).

Tip number 3: please apply your sunscreen at least 15 minutes before heading out for your workout. This will give it time to absorb and start to give you sun protection as well as decrease the chance you will wipe it off the first time you mop your brow with your shirt.

Tip number 4: please hydrate before you exercise as well as during and after. Hydrate means water!! Coffee, tea, soda and milk all dehydrate you and don’t count towards your daily intake of fluid. Try to drink 8 ounces of water within an hour of your workout, 8 ounces for every 30-60 minutes of exercise and at least 8 ounces immediately following your workout. This is not a hard and fast recommendation so please listen to your body and consult with your MD if needed based on your individual hydration needs.

Tip number 5: please consult with your MD regarding exercise in hot conditions if you have any significant medical issues, for example cardiac issues. Someone who knows your specific medical status will have the best advice to modify workouts in hot weather.

Last piece of advice; have fun, stay safe and let’s enjoy our short and humid New England summers to the fullest!

Dr. Clark-Fox is a Physical Therapist at Boston Sports Medicine