Some folks feel the heat, while others have really felt the heat. One of the advantages of having a running background is that it tends to condition you to the effects of heat on performance. Cycling tends to insulate you somewhat since you often have easier access to liquids (aka, bottle cages) and have an inherit cooling effect (aka, the faster you ride, the more wind you generate). However, either can be lethal under the right circumstances; but mostly likely just affect your performance.

I have too many heat related running stories to tell you, so I’ll simply show you some data (one advantage of cycling) to how heat affected my performance.

OK, let’s look at this past Sunday. I went on a 80+ mile ride with one of my teammates. Both of us had been on several 4+ hour rides since January, but nothing when heat indexes were in the 90s. Well, we weren’t ready and the data shows it.  Let’s just say I felt as if I was on the Bataan death march the last 30 miles. How, so? Here’s data from one ride segment:

Notice that I had a HR of 165 bpm and was only going 17.1 MPH and putting out 159 watts. Now, let’s compare to a ride later in the week when temperatures were in the upper-60s:

Here I had a HR of 165 bpm and was only going 21.3 MPH and putting out 250 watts. Same HR, but a big difference in speed and power on the same stretch of road. I always knew heat affected me, but it’s interesting to now see it in the numbers. The good thing about riding in the heat is it conditions you for racing in these conditions.