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Training Tips

Training and Racing Safely in the Heat

Use the Same Heat Training Techniques Team USA is Relying on for the Tokyo Olympics

The Olympic Games in Tokyo are expected to be one of the hottest Games ever, and coaches and sports physiologists have spent years preparing protocols to help athletes perform at their best as temperatures soar. The great news is that you can utilize the same tools and methods used by the world’s best to improve your performance in the heat.

Heat Acclimation

Heat acclimation is the process of stimulating physiological adaptations that allow athletes to perform better in hot environments. The key responses to chronic heat exposure include: an earlier onset of sweating, an increase in sweat rate, decrease in sweat sodium concentration, blood plasma expansion leading to lower skin and core temperature, and a return to normal exercise heart rates (after being elevated before acclimation). (Périard, Racinais and Sawka 2015)

Time course of adaptations from heat acclimation
Time course of adaptations from heat acclimation. Adapted from Périard, Racinais, and Sawka 2015

In order to acclimate to heat you need to raise body temperature for prolonged periods, which can be accomplished by exercising in a naturally hot environment or a heated room, controlled hyperthermia (overdressing), and passive heating (sauna or hot water immersion).

All of the methods above work, but exercising in a hot environment or overdressing will have a negative impact on workout quality. Post-exercise passive heating is the preferred method for this reason. Working up to about 30 minutes in a dry or wet sauna or hot tub after exercise (2-3 hours endurance pace or 90-minute intense interval workout) for 7-10 consecutive days is a good starting point for an effective protocol for heat acclimation. If you are not exercising prior to the passive heating session, increase the duration to 45-60 minutes.

How long do the advantages from heat acclimation last?

The degradation of heat acclimation begins about 48 hours after the last heat exposure, but the loss of heart rate, sweat rate, and core temperature control are gradual. Even better, you can maintain nearly all your heat acclimation adaptations with a heat exposure once every three days after the initial protocol is complete.

Note: Heat acclimation interventions should not take priority over fundamental aerobic and event-specific training. Fitness is your best weapon because it makes your natural cooling mechanisms more effective and increases your capacity to adapt to and cope with adversity.

Even athletes who are acclimated to high temperatures experience a drop in performance when training or competing in hot environments, so it is important to take steps to lower skin and body temperature before, during, and after exercise.


The goal of a pre-cooling strategy is to lower core and/or skin temperature before exercise in order to give the athlete more time before body temperature rises to the point thermal strain hinders performance. Many methods have been researched, and most of them are simply impractical. The most practical and effective methods for pre-cooling are ingesting ice slurry drinks (to lower internal temperature and thereby increase heat storage capacity) and applying ice packs, cold towels, or ice vests to the skin to lower skin temperature and create a bigger temperature gradient between the body and the environment.


The effects of pre-cooling don’t last very long once the starting gun goes off, particularly for endurance cycling events that last from one to several hours. Staying cool during prolonged activities in hot weather comes down to dousing yourself with cool water, wetting your clothing, and wrapping ice socks around the back of your neck or carrying them in your jersey.

Hydration status is also critical to staying cool during exercise in high temperatures.. Your blood plasma volume is your reservoir of potential sweat. Heat acclimation increases plasma volume and if you are expecting extreme temperatures you may want to consider hyperhydration drinks that are designed to further increase fluid retention. Consuming water and sports drinks during exercise replenishes a significant portion of the fluid you’re losing through sweat, allowing your primary cooling mechanism to continue working. You want to consume cool to cold drinks, but not the ice slurry beverages you may have used during pre-cooling


Core temperature is typically elevated at the conclusion of an exercise session or competition in a hot environment because of both exertion and mild dehydration. Taking proactive steps to reduce core and skin temperature immediately after exercise is important because you still have a lot of internal heat storage but stopping immediately eliminates most of the airflow that had been facilitating evaporative cooling and the skin-to-environment temperature gradient.

Dousing yourself with cool water, applying wet towels and ice packs, and drinking cold beverages are all effective for cooling down after a workout or competition. Pedaling lightly is also helpful because it maintains mildly elevated blood flow, which helps to transport heat from the core and muscles to the skin. If you are spinning around the venue or side streets you also have some airflow to help with evaporative cooling. If you are riding a stationary trainer, incorporate one or more fans to create airflow.

What you might see at the Olympic Games

When you watch Team USA at the Tokyo Olympics you are likely to see cyclists wearing ice vests prior to the start of events and/or between heats. During the road race and cross-country mountain bike race you may see riders using ice socks on their necks or in their jerseys, as well as dousing themselves with water throughout the event. These are relatively low-tech, inexpensive techniques that can be conveniently and reliably executed in a wide range of circumstances, which makes them perfect for both everyday use and the world’s most important events.


Kakamu, T., Wada, K., Smith, D. R., Endo, S., & Fukushima, T. (2017). Preventing heat illness in the anticipated hot climate of the Tokyo 2020 Summer Olympic Games. Environmental Health and Preventive Medicine,22(1). doi:10.1186/s12199-017-0675-y

Périard, J. D., S. Racinais, and M. N. Sawka. 2015. “Adaptations and Mechanisms of Human Heat Acclimation: Applications for Competitive Athletes and Sports.” Scandinavian Journal of Medicine & Science in Sports 25: 20–38. doi:10.1111/sms.12408.

Racinais, S., Alonso, J. M., Coutts, A. J., Flouris, A. D., Girard, O., González-Alonso, J., . . . Périard, J. D. (2015). Consensus recommendations on training and competing in the heat. Scandinavian Journal of Medicine & Science in Sports,25, 6-19. doi:10.1111/sms.12467