Effects of Heat on Conditioning

With many teams getting back outside to prepare for the upcoming fall season, it’s time again to talk about safety. Over the weekend, I wanted to look at what effect the heat has on heart rate and recovery heart rate. I pushed one of our Cybex Arc Trainers out into a covered garage area where it was shaded, but the temperature was still 96 degrees (no breeze and very humid). I performed a 4 minute on 1 minute off interval conditioning program for 30 minutes (blue line in the graphic below). Then 48 hours later, I performed the same interval indoors where the temperature was 75 degrees (red line in the graphic below).

Here are a few things to take notice of:

  1. HR is almost 10% higher in the 96 degree temperature vs. the 75 degree temperature
  2. HR recovery is much worse in the warmer temperature
  3. Focus was was compromised once HR hit 90% of max (resulting in going to long on 3rd interval in blue)

As you get your teams out on the field this fall, please take note of this. We are all concerned with the heat this time of year, but sometimes we don’t realize the effect it has on heart rate. We sometimes think that the players need to “tough it out” and sometimes we might even assume that they haven’t been training in the preseason and they are a bit “out of shape.” And while this might be the case sometimes, we still have to take into account the effect heat has on HR and therefore fitness and recovery. Players that might be very fit can sometimes appear to have a reduced level of fitness simply due to the heat.

This can be very dangerous, and I would caution all coaches to be aware of this as you hit the field this fall.



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