Running in high humidity: 7 important tips

Running in hot weather in conditions of high humidity has its own specifics, so athletes should prepare for such loads with special care.

To find out how to run safely in this climate, we spoke with Vladislav Demyanov, an experienced marathon runner living in Thailand, coach and author of Lifetime Running.

what happens to the body

During any physical activity, the body temperature increases. To prevent the body from overheating, excess heat is excreted from the body in the form of sweat. At normal humidity levels, moisture evaporates quickly from the skin. But when the percentage of humidity is high enough, evaporation becomes more difficult, the body overheats, and the load is more difficult to bear.

It turns out that humidity is a powerful catalyst for all the processes that already occur in the body when running. A high percentage of humidity enhances the effect of air temperature, which leads to an increase in heart rate and increased sweating.

How to run in high humidity 7 important recommendations
Humidity increases the sensation of temperature. Source:

In addition, excessive sweating leads not only to fluid loss, but also to a decrease in electrolytes in the athlete’s blood. The blood thickens, dizziness occurs, the heart rhythm is disturbed, and blood pressure decreases. This condition can lead to fainting.

What is a Heat Index?

By itself, a high temperature is not so terrible for an athlete, it is the humidity that exacerbates its effect. If it is +30 degrees outside and the humidity is 90%, then the temperature will feel like +40°. At 30-40% humidity, the temperature feeling will almost coincide with the actual situation.

The heat index is used to relate air temperature and humidity percentage. The Heat Index formula helps athletes relate to weather conditions and use this information to plan their training process. The easiest way to calculate the heat index is to use online calculators.

How to assess your form before a race

It is quite difficult to do this in advance, since a lot depends on the distance. During a 5 km race, dehydration will not have time to set in. On the “top ten” you can roughly assess your form by doing tempo workouts. And for a half marathon or a marathon, it is simply impossible to draw conclusions before the start.

Here it is important to take into account how well the athlete is ready to eat, how competently he distributes his forces over the distance itself, how he maintains water balance during the race and how he recovers after training.

How to reduce stress on the body

Acclimatization plays a big role. To reduce the load, it is recommended to arrive in advance at the place of the race. In 2-3 weeks, the body adapts to new conditions and will more easily perceive a climate with high humidity.

During long rides, it is better to drink not plain water, but an electrolyte or isotonic/rehydron drink. This is necessary to maintain the balance of electrolytes in the body.

After training with a large loss of fluid, it is better to drink isotonic and consume citrus fruits for a more effective recovery of the organism.

How to run in high humidity: 7 important recommendations
Favor short-tempo workouts, they dehydrate the body less. Source:

How to prepare for a race

what to eat

Nutrition is one of the key factors for running in high humidity. If you eat foods with a small amount of electrolytes before a certain distance, useful elements (potassium and sodium) will quickly leave the body with sweat.

Choose electrolyte-rich foods, such as watermelon and citrus fruits. Potassium, responsible for maintaining water in cells, is found in dried apricots, raisins and bananas.

Ditch the flour. Such food requires a lot of resources for assimilation, removes water from the body and removes useful substances. It is better to give preference to fruits and vegetables, which provide the body with fluids and electrolytes.

How and what to drink

Just like when running in familiar weather, when running in high humidity you need to drink little and often. It is very important to maintain not only the water balance, but also the concentration of electrolytes. If the blood becomes less saturated with electrolytes, dizziness and seizures begin. This can lead to serious consequences for the body, up to death.

The day before the race

It is necessary to properly saturate the body with electrolytes, that is, to drink rehydron or isotonic. The main difference between these two drinks is that isotonic contains electrolytes and carbohydrates while rehydron only contains electrolytes.

In an hour to escape

Unlike running at normal humidity, you don’t have to do a long warm-up here so you don’t lose a lot of fluid before the start. Stretch, warm up in a cool place, if there is one. Reduce monotonous jogging time.

How to behave remotely

You don’t need to splash too much water, even if you want to. The pleasant sensation will last for the next 500 meters, after which water will penetrate the shoes, adding weight to them and causing friction.

Instead of watering, it is better to use damp sponges. You can also apply a piece of ice to the forehead and temples. This will give a positive effect, albeit in the short term.

How to run in high humidity: 7 important recommendations
To relieve the condition, wipe the forehead, neck, temples with sponges. Source:

When you run in high humidity, you have to be very proficient at distributing the forces. At the start of the race, there may be an illusion that the race is easy. In fact, the humidity makes itself felt only after 3-5 km. Therefore, avoid jolts and accelerations.

At food stations, it is better to slow down a bit. During running, breathing is lost, and when a person also drinks, oxygen begins to run out. Therefore, slow down while drinking so that there is no oxygen debt.

Finally, a factor such as experience plays the most important role. The more often you start in uncomfortable conditions, the better the body adapts to it.


To successfully cover the selected distance in high humidity, the following items are required:

  • Acclimatization. It’s best to arrive in the race area a few days early and let the body adjust.
  • Appropriate food. This point must be started well before the race itself. Introduce foods rich in electrolytes into the menu: watermelons, citrus fruits, bananas, raisins, dried apricots. And limit flour, which takes water from the body.
  • Way of consuming. Drink little and often. For running, take not only water, but also isotonic or rehydron.
  • Short workouts. Do not expose the body to long exhausting workouts that lead to dehydration. It is better to switch to short tempos.
  • Competent distribution of forces. Do not accelerate at the start of the race. The feeling that running is easy is misleading.
  • Short workout. Opt for stretching in the shade rather than running before you begin.
  • Remote sponges and ice. After watering, the water will begin to evaporate strongly and add discomfort when running. Use sponges or rub ice on your temples, neck, and forehead.

Read more: 7 important rules for exercising in hot weather

We thank Ksenia Zorina for preparing the article.