Don’t Let The Heat Get You Down!

Summertime is here and all of us are struggling out there, even the fastest runners are slowing down, here’s why:

For every 10-degree increase in air temperature above 55 degrees, there’s a 1.5 percent to 3 percent increase in average finishing time for a marathon.  We are slowing down because heat impacts runners at a physiological level through increased dehydration and heart rate and reduced blood flow (and subsequently oxygen) to the working muscles used for running.

Some ways to minimize the negative effects that summer heat has on your run performance are:

1)  Continue to train in hot conditions because this will result in higher blood plasma volume, increased sweat rate, decreased salt in sweat, reduced heart rate at a given pace and temperature, and a quicker onset of sweating.  All of these adaptations will make it easier to run well in the heat, and adaptations will take place after only a week or two of heat exposure.  

2)  Adjust your expectations on particularly hot days.  Modify your workout to reflect the way you are feeling using perceived effort as a guide.  This will mean moving away from a time goal to the equivalent effort.  This is an important lesson for any athlete and one that can be used when conditions are adverse – not just for running in hot weather but also on very hilly terrain or windy days.

3)  Take measures to lesson the effect heat has in your preparation for a race in warm weather by consuming more electrolytes in the days leading up to and during the race.  Be careful not warm up too long especially before shorter events, and stay as cool as you can prior to the race with cooling towels for your neck or sipping on an icy drink.

Before you head out on your next run, check the dew point,  The dew point indicates the amount moisture in the air. The higher the dew point, the higher the moisture content of the air at a given temperature. Therefore, the dew point is more significant to runners than temperature and humidity as it provides a strong indicator of how they will feel while running.  





Very comfortable

PR conditions



Hard efforts likely not affected


Uncomfortable for some people

Expect race times to be slower than in optimal conditions


Uncomfortable for most people

Easy training runs might feel OK but difficult to race well or do hard efforts


Very humid and uncomfortable

Expect pace to suffer greatly

75 or greater

Extremely oppressive

Skip it or dramatically alter goal

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