Keeping Cool and Power Loss

For the last 2 years of indoor training, i only used a 12 inch desk fan and window opened for keeping me cool, but i always felt i was over heating during hard intervals. So last week i purchased an 18 inch floor fan what a difference.
On Christmas Day i completed the 20 minute FTP test. For the first 10 minutes my power transfer was slightly above my FTP which felt to easy, this is normally when i’d start to overheat. With the high powered fan keeping me cool, i pushed on and smashed the last 10 minutes, 320w - 4.8w/kg. Yesterday i completed Wilhelm+5 which consists of 7X5 min VO2 intervals, yet again smashed them.
What i was wanting to know, How does overheating effect performance?


A lot has been said on both the forums and on the podcast episodes. Try to search a little.

In short: Overheating affects your performance more than you might think. I use 3 fans in a cold room - otherwise my performance suffers.


Yes, overheating has a huge impact on your performance. The brain actually reduces the number of nerve signals to the muscles, which means fewer muscle fibers will be activated. This obviously drastically reduces performance!



Overly simplified, the body will begin to limit power output capacity when its efforts at cooling (via sweat) fail to reduce core temp.

It is a preservation response that is meant as a secondary measure to reduce heat since the sweat is not successfully doing the job.

As you found, air flow for effective evaporative cooling is very important and likely overlooked by many.

A pool of sweat under the bike is not a badge of honor. It’s a sign of inadequate cooling.

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I found this webinar helpful. I used to live in Texas and it was always super hot there so I started looking into this.


That Triathlon Show just recently had Andrew Buckrell of STACZero on their podcast to talk some particulars about this - the why and how, as well as mitigation and dealing with heat:

I found it extremely illuminating.


This is quite topical because I’ve been doing workouts in a gym this week while visiting my in-laws. The spin bike room was 74 degrees and I used a large fan that they have, but I wouldn’t really say it’s better than my lasko fans. Anyhow, for a 92% sweet spot effort my HR was upper 160s where at home in a 55-65 degree basement it’s been lower 150s lately. Of course there could be power measurement differences between the stages spin bike and my Hammer, but the environmental factors definitely made a difference I think

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I think I am going to breakdown and buy the wahoo fan. My wife and I have a smaller space and that fan would do the trick. In the FTP test, I can hold quite a bit more power for about 12 minutes and then I can feel the heat build and the sweat just boils on my skin.

I’d rather hammer outdoors in Texas in the heat than ride 30 minutes indoors with no fan. at least outside you have airflow and the sweat is doing it’s job. I just have to carry 3 liters of water as I lose about 4 -5 pounds per hour.

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You are probably aware, but you could buy 2 Lasko Performance Blower fans the less than the Wahoo Headwind. You won’t have the auto features, but 2 of those Lasko fans will likely beat the single Headwind.

Just an option if you haven’t considered it.

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What @mcneese.chad said. The Wahoo fan did not get rave reviews. Save your money and get a Lasko.

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For us riders outside the US, the lasko is not an option. However, the headwind is easily available, if only you don’t try to get one just a day before the Christmas, like me.

There must be other blower fan brands available. I’d search a bit and compare. Nothing really wrong with the Headwind other than the astronomical price.