Heat Training 101

As the peak of Summer nears and the year's highest temperatures in the Northern Hemisphere approaches, I thought it would be fitting to discuss the benefits of training in the heat. Not surprisingly, there is now compelling evidence that suggests that training in the heat (> 90F / 32C) is just as effective as training at altitude. Some benefits include increased red blood cell production, increased plasma volume and thermoregulation, and better cardiovascular efficiency. I, therefore, encourage all cyclists to try to not avoid training on hot summer days, but rather to embrace the heat and all the benefits involved.

In the past, heat training was primarily used as an acclimation approach to hot race days. However, recent research suggests that there are even more benefits to heat training than we thought. As a result, many ambitious cyclists have been recently targeting heat training not only for better thermoregulation, but also for increased performance on the bike. A study done by the Journal of Applied Physiology, concluded that after just 10 days of heat acclimation, subjects experienced a 6 - 7 % increase in red blood cell production and plasma volume. [1] A 6 - 7% increase in plasma volume also directly improves lactate threshold, V02 max, and overall performance on the bike.

With that being said, some important heat training guidelines are the following:

1. Target training at temperatures above 90F / 32C.
2. Target 90 - 120 minutes in the heat for best results.
3. Best adaptations occur around 10 - 14 days after riding everyday in the heat.
4. Recommended to ride in Zone 2.

Mistakes to avoid:

1. Heat is good for the body, but the sun is not. Use lots of sunscreen!
2. Dehydration. Fluid and electrolytes are lost quicker in the heat.
3. Under fueling. Glycogen levels in the body are burned much quicker in the heat. Bring sugar and gels.
4. Do not approach heat training as intensity training. (Make an effort to ride just in Zone 2)

Heat training guidelines for the winter months:

1. Ride on an indoor trainer in a closed room.
2. Overdress with base-layers and jackets to increase core body temperature as much as possible.
3. Target same time and intensity as mentioned above.

Signs that your body is adapting well to heat training:

1. Lower heart rate at same power in the heat.
2. Better hydration tolerance.
3. You are producing more sweat and sweating earlier during training.

In summary, the key heat training variables are duration, intensity, consistency, and environmental heat load. It is also important to note that heat training is most effective when maintaining an elevated core body temperature for a sustained period.

Enjoy the Summer and enjoy the heat!

Sources:

[1] Lorenzo, Santiago, John R. Halliwill, Michael N. Sawka, and Christopher T. Minson. "Heat Acclimation Improves Exercise Performance." Journal of Applied Physiology 109.