If you have been watching the 2016 Olympics in Brazil you may have seen events such as: swimming, gymnastics, golf, diving, gymnastics, tennis, court and beach volleyball, and now track and field.  For some of these events, it has been all indoors. For others there have been the elements of the weather.  In fact, the temperature in Rio, Brazil has been ranging from 70-90’s degrees fahrenheit with around 70% humidity.

In those type of elements it can dramatically affect ones performance.  To show how much heat and humidity can impact ones body while being physical active, specifically running, here’s some info from Jeff Galloway’s Book on Running (1984):


Air Temp

Per Mile Adjustment for Heat

Per Mile Adjustment for 60% Humidity

Slower than your Goal Pace

50° F




55° F

add 5 secs

add 10 secs


60° F

add 15 secs

add 25 secs


65° F

add 30 secs

add 45 secs


70° F

add 40 secs

1:05 min


75° F

add 1:10 min

add 1:45 min


80° F

add 2:00 min

add 3:00 min


What does this chart actually mean? Anything over 85 degrees will impact your pace by as much as 20%. For instance, if the heat index is in the upper 80’s and the humidity is 65% giving it “your all” actually equates to 80% of total max when the environmental elements are not ideal. For a runner, this means if you typically run a 10 minute mile you were running more like a 13 minute mile in these conditions.

So what is one suppose to do in the summer heat when training and/or competing, you ask?


Heat–> When the temperature rises the body loses more water through sweat. It also demand more oxygen to the muscles.

  • Wear light weight and loose fitting clothes
  • Do not wear a hat to allow heat to escape
  • Hydrate, hydrate, hydrate with water and products that provide carbohydrates and sodium such as Nuun.

Humidity–> Relative humidity is the amount of water in the air and when those levels are high the body has a hard time staying cool. Meaning: sweat stays on your body and doesn’t evaporate making it hard for your body to stay cool.

  • Train in shade and/or indoors
  • Train in the mornings
  • Hydrate, hydrate, hydrates with 4-8 oz of fluid every 15-20 minutes.

The best things to do is prepare yourself for the heat when training.  Think things through from the outfit that is best for your outdoor activity, to the time of day, to even the food that you will be consuming both the night before and the day of.  Just make sure that fluids are a high priority to avoid heat exhaustion.

Happy Training.