Heat Acclimatization Can help Exercise Performance

Other than the heavy rain the last two days, it's been very hot recently. I used to love training and racing in the heat. Living in sunny and super humid Singapore meant that we're used to such conditions.

I'll often train in the hottest part of the day so that when race day came, whatever sweltering conditions encountered (on race morning) will seem like a breeze. There was a year (2001) when the Osim Singapore Triathlon was held in Sentosa and it was 38 degrees Celsius on race day and I used that advantage to finish 3rd overall behind Dimitry Gagg (former World Triathlon Champion in 1999).

On the podium with Dimitry Gagg in 2001

Turns out I may have been right in getting an edge over my competitors. And you can use that to your advantage too.

Heat is now hot! This shift towards heat training has been trending for the past few years. From running marathons to even climbing mountains, athletes around the world have been trying to get potential performance benefits of heat training.

Many of these heat studies started because of the 2008 Beijing Olympics. Many runners were preparing for the sweltering conditions and that lead to a whole lot more research done on heat acclimatization.

There are even studies of using heat therapy to fight heart disease and repair muscles.

Most heat acclimatization protocols help athletes perform better in the heat. This includes lowering core body temperatures, increasing perspiration rates and increasing volume of blood.

And what if after all that training in the heat race day wasn't hot? What if race day turns out to be as cold as the 2018 Boston marathon?

Fret not, results of a study (Lorenzo et al, 2010) on whether being well adapted to heat might affect your performance in cool conditions put that worry to rest. Scientists had cyclists train for ten days in 41 degrees Celsius (105.8 degrees Fahrenheit). Their VO2 max improved by 5 percent while their one-hour time trialing performance improved by 6 percent! This was when they were tested at 12.8 degrees Celsius (55 degrees Fahrenheit). Just in case you were wondering, they improved by 8 percent in hot conditions for both VO2 max and the one hour time-trial.

Control group cyclists had no improvements in V02 max, one-hour time trial performance, lactate threshold and other physiological parameters.

Suddenly, hot rooms, saunas and even non breathable training suits were the latest must haves and even suggested to be a cheaper and more convenient alternative to altitude training.

When it is too hot, it is a shock to our system. This is similar to what happens to our system when we exercise or train in altitude.

When we exercise in altitude, the decrease in oxygen triggers the body to produce more red blood cells. Heat training increases the volume of blood plasma in our bodies and this help send more oxygen to our muscles.

However, it is not totally certain that increasing blood plasma volume may lead to improved athletic performance. What may happen from the resulting dilution of blood is that it may trigger a natural response for the body to produce new red blood cells - just like altitude training.

Training in hot conditions does not only change blood plasma. Other benefits include psychological resilience (or the ability to endure) and altered perception of high temperature. Just like what I intended for by training in the hottest part of the day.

Before you head out and train yourself silly in the heat, make sure you gradually increase your intensity and heat exposure. Drink enough but do not overdrink.

Reference

Lorenzo S, Halliwill JR et al (2010). Heat Acclimation Improves Exercise Performance. J App Physiology. 109(4): 1140-1147. DOI: 10.1152/japplphysiol.00495.2010.