Heat Adaption for a Hot Race

For some athletes, heat training is a season-long strategy meant to reap the performance gains that come from increased blood volume. Other athletes prefer to do heat training for a limited time, usually in preparation for a specific event that will occur in a hot climate. For these athletes, we offer a simple protocol for heat adaption for a specific event.

While the protocol itself is simple, it can be challenging to blend it into an athlete's regular training program. And, remember that doing too much heat training does not provide additional benefit. Instead, too much heat training can leave you exhausted and be a setback for your training. “Too much” can occur either when your core temperature goes higher than your heat training zone, or when you exceed the recommended amount of time per day of heat training. For safety and effectiveness, we recommend working with an experienced coach.

Two to four weeks in advance

The number of days required for heat adaption varies amongst individuals, but fourteen days works well for most athletes. Depending on travel plans and how heat training meshes with other workouts, you'll want to begin your heat training two to four weeks before your event. If you complete the heat training block more than a couple of days before competition, you'll want to do maintenance heat training until the start of the event.

Step 1. Heat ramp test

Your first step is to complete a heat ramp test (instructions here). If your last heat ramp test was more than 8 weeks ago, or if you've made a significant change in the amount of heat training you’ve done since the test – you'll want to do another. Completing the heat ramp test will identify your heat training zone.

Step 2. Heat block training

The second step is to complete two weeks of heat block training. This involves training 45–90 minutes each day with your core body temperature within your heat training zone. For more details, see the guide for heat training.

Warm climate or extra clothes

You can do heat training either by exercising in a warm climate, by wearing extra clothes, or some combination of both. Regardless of the method, your goal is to elevate your core body temperature into your heat training zone.

A few possible strategies:

Do your heat training at the event site for two weeks preceding the competition.
If you live in a warm climate but normally train during the cool of the morning/evening, do your heat training in the hotter part of the day.
Simulate a warm climate with indoor training in a heated room, using boiling water or humidifiers to increase the humidity.
During training, wear more clothes than normal. The right amount of clothes will depend on a mix of workout intensity, ambient air temperature, and humidity,

Passive heating

Passive heating can complement active heat training. It increases your heat training time with less fatigue and impact on normal training routines. A heat workout can be extended by using a hot bath (40 °C/104 °F) or sauna (70–90 °C/158–194 °F). Please note that the CORE device is not yet recommended for use in the sauna.

Core body temp is most relevant

The most important part of heat block training is raising your core body temperature into your personalised heat training zone for 45–90 minutes per day. This is true for whichever strategy is used for heat training, and regardless of the ambient air temperature.

Step 3. Heat training maintenance

If your two-week long heat block training ends more than a couple of days before your competition, you will need to maintain your heat training. This requires elevating your core body temperature into the heat training zone for 45–90 minutes per day, 2–4 days per week. This can be done with the strategies discussed in the heat block training section.

Step 4. Pre-cooling

Pre-cooling immediately before the event can help slow the rise of core body temperature once the event begins. A simple strategy involves doing your warm up in the shade. Active strategies like ice vests and cool baths can be more effective and provide a major benefit. However, pre-cooling strategies are very individualised and should be tested and refined during training.

Step 5. Thermoregulating

During the event, your CORE sensor can remind you to take cooling strategies before your body temperature reaches a level that causes performance degradation. Strategies can include hydration, clothing adjustments, and external use of ice and water. These strategies should be practised in training to identify the most effective for your particular needs.

Additional Resources

CORE's Heat Training for Sporting Performance

Beat the Heat: Tokyo Olympic Games 2020 This pdf gives excellent suggestions for training and competing in the heat.