With the hot weather and humidity settling in, some runners find it very challenging to train in that type of weather. Running in hot weather has many benefits for increasing our performance and fitness level. Training in the heat adds extra settings to your blood flow (hypervolemia). Blood volume is the sum of red blood cells and plasma volume. Red blood cells transport oxygen, while more plasma allows your heart to pump more volume per beat per minute (greater cardiac output). Blood volume is a big determinant in performance, and it can change with proper heat training.
Training in the heat can increase the rate of perspiration, increase a runner’s blood plasma volume (which leads to better cardiovascular fitness), reduce overall core temperature, reduce blood lactate and even increase skeletal muscle force. Heat acclimation can be as efficient or even more than altitude training. Heat acclimation provides more substantial environment specific improvements in aerobic performance than altitude training. Heat training not only does a better job at increasing VO2 max, but it also makes runners better at withstanding a wide range of temperatures.
Training in the heat properly can have extraordinary effects. Studies have shown that heat training not only can expand blood plasma volume, but there seem to be some changes in the heart’s left ventricle, which helps to increase oxygen delivery to the muscles. Runners who train in hot weather, tend to get better at regulating heat by sweating earlier and developing a colder resting body temperature. Training in hot weather, runners have to compromise training quality for the heat acclimation. When starting to run in hot weather, the heat is additional stress to the body just like more intense training sessions (intervals) or running longer distances. One important factor is that not everyone responds to running in hot weather at the same rate or physiological gains. Some runners suffer more from the heat than others, some need more hydration. To focus on consistent and quality training is very important even as a safety issue.
How to train in the heat?
- Train consistently
The most efficient way to increase blood volume is training consistently. After 10 days to 2 weeks, the level of red blood cells increases. The body adapts to the heat, the blood volume increases, the fitness level increases, and the VO2 max increases as well. When running in the heat, runners need to focus on consistency rather than epicness. A great consistent training plan is to run 5 days/week. After 10 days, once the body starts adapting to the hot weather, mixing a day or two of higher intensity efforts, interval training or cross-training is even more productive.
When running in hot weather, and especially high humidity, our body gets depleted quickly of basic minerals and electrolytes. In any training session over one hour, runners need to include some electrolytes in their drink. In more intense or interval training sessions, when you push hard, including electrolytes even for under one hour is important.
- Focus on quality runs
Once the heat settles in, runners have to remember that their performance and time will drop. That is part of the body’s acclimation. If you train in the heat for at least a few weeks, and then travel somewhere with cooler weather, you will see a huge difference in your performance and stamina, your run will feel so much easier. At first, make sure you focus on consistency and endurance, not speed and sprints. Running in the heat can be extremely difficult for some runners. It might feel like an intense training session, which actually it is very similar to doing a hard run. Running in hot and humid weather has to be a balanced training session, done very reasonably to get all the benefits after a while.