It’s June. Summer time for people like me living in the Northern Hemisphere. It's getting hot out. But I love it.

Having grown up in cool, wet and cloudy, Vancouver, Canada, the draw of sunshine and heat is one of the main reasons I chose to pick up sticks and move to Australia, the sunburnt country, to do my doctoral work in 2000.

As most of us know from experience, heat changes the game when it comes to exercise and performance. Because heat is on my mind, I’ll use this topic as a springboard for a series of issues it brings out.

Today will be super simple to get us started. As we go, be sure to draw on your own past experiences in the heat to reflect on. To begin, maybe consider your viewpoint on whether you go well, or not so well in hot conditions. My observations are that this tends to be quite variable across individuals, for reasons we will get to.

So does heat affect you? Inevitably yes. You’re human.

My real learning in this area started with a story told by one of my mentors in the field, Dr David T. Martin. Dr Martin is an American who spent the majority of his career at the Australian Institute of Sport, and was specifically embedded in the Aussie cycling program.

It was 1995, and David tells the story of working with the head cycling coach, where he had a final group of eleven cyclists who were to be chosen for the Olympic cycling team to represent their country in the Atlanta 1996 Games. Only 3 get selected. The performance staff decided that one of the key selection criteria would be how athlete's performed in a hot and humid laboratory setting — similar to what they would experience in Atlanta.

David reflects on some of the athletes coming into the lab. As with many of us athletes, we often arrive at sport with a degree of ego in hand, and there was no shortage on display for these tests. The general consensus of the cyclists was that heat played no role in how well they could perform. Bravado comments a plenty — "the heat doesn’t affect me, Dave. You’ll definitely want to choose me".

Onto the test, with the data published as Tatterson et al. (2000). The cyclists arrived at the lab on two separate occasions where they performed a 30-minute all out cycling time trial in a controlled environment. One of the tests was conducted at a normal 23°C and 60% humidity, while the other was performed at 32°C and 60% humidity (expected Atlanta conditions). Now remember, this test was being conducted in some of the best cyclists on the planet at the time.

What do you think happened?

As you can see by the results, the study found that power output was 6.5% lower during the hot and humid trial compared to normal conditions. The cycling superstars were human after all.

Right, so I think we can all agree that heat will affect our exercise performance. But before we start digging into ways upon which we can lessen its effect, we should do our best to understand why this reduction occurs.

And that will be next week.

Class dismissed,

Paul

Paul Laursen, PhD

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