What is the right way to run in hot weather. Answered by an ultramarathoner

ultramarathoner, founder and coach of the ERA running club

What are the dangers of jogging in the heat? What time of day can you run in the summer?

Every summer Moscow is covered with heat for two or three weeks, and this time becomes a serious test for everyone who does sports outdoors. Physical exertion in hot weather is not pleasant to many people, the results of training are lower, and hard work in the heat can pose a health risk.

Is it safe to run in the heat

For a novice runner, the first, even short (no more than half an hour) jogs in the middle of the day under the scorching sun are not the best way to enter the world of running. It’s unpleasant and unsafe. On the other hand, the abundance of running activities in the summer makes running in the heat a necessary skill, and you can’t do without training altogether.

As a rule, it is most comfortable for a person in open clothes to run when the air temperature stays around +15°C in windless weather. It is often difficult to run for a long time at +25°C and above. And when the temperature exceeds +30°C, few people will risk to go out for training with a long or intensive load. And they will be right.

What is the danger of running in hot weather

Muscle work is inevitably associated with the release of heat. Only about 20% of the energy that is expended during muscle contraction is converted into movement. The rest is mostly released in the form of heat, this heat is absorbed by the tissues surrounding the muscle fibers and increases the temperature of the blood flowing away from the muscles. The body gets rid of excess heat through several thermoregulatory mechanisms. The most powerful of these is sweating. Sweat, evaporating from the surface of the skin, reduces its temperature. In addition, if the air is cooler than the skin, there is a direct transfer of heat from its surface. A small amount of heat also escapes with exhaled air.

Overheating

If for one reason or another the thermoregulatory mechanisms fail, overheating occurs. Locally – at the level of muscles – excessive temperature increase reduces their performance. General overheating of the body (especially the brain) can be dangerous to health and even life.

Heat cramps

Heat cramps, involuntary contractions of muscles (most often calf, posterior thigh and anterior thigh), are a fairly common problem during prolonged intense exercise in the heat. Although they can be very painful, heat cramps are not very harmful to health. Resting in the shade and drinking enough water can help relieve them, although some muscle soreness may persist the next day.

Heatstroke

Heat stroke is a much more serious condition, often requiring medical attention. So if you experience balance problems, dizziness, changes in consciousness (drowsiness, confusion, loss of consciousness) while running, you should move into the shade as soon as possible and take measures to cool your body. Cool drinks, dousing with water, wetting clothes with water, etc. may help. If the condition does not improve, you should call an ambulance.

Dehydration

There are two other conditions associated with prolonged exercise in the heat. One of them is dehydration. It is believed that loss of more than 2% of body weight with sweat (for example, for an athlete weighing 70 km this corresponds to 1.4 liters, most people sweat during exertion ranges from 1 to 2 liters per hour) causes a significant decrease in physical performance. At the same time, trained athletes can lose more than 5% of their body weight in sweat and still win competitions. As a rule, the symptoms of dehydration (thirst, dry mouth, scanty urination and dark color of urine) indicate a large loss of water, which can not be compensated for in the course of exercise – you can only slow down the rate of loss.

What is the best thing to drink in the heat, read in this article.

Hyponatremia

The second condition is hyponatremia, that is, a decrease in the concentration of sodium in the blood. This condition is associated with excessive fluid intake. It usually occurs in slow runners in marathons, Ironman triathlons and other events who take a long time – more than five hours – to cover the distance. They drink a lot of fluids, not realizing the amount of fluid they have consumed and the amount they have lost. Hyponatremia is manifested by nausea, vomiting, weakness, dizziness and impaired consciousness. This condition requires medical attention.

What is the best thing to run in

From obvious considerations, the more skin surface open to heat transfer the better, so it’s best to run in short form in the heat, but with one important caveat. Direct sunlight will cause your skin to burn, so it’s worth using sunscreen. If you have to run for a long time in the heat under the bright sun, light-colored clothes with long sleeves may be useful.

It is worth recalling once again that maximum heat transfer and sweat removal are provided by synthetic fabrics, no clothing made of natural fibers in the heat (and in general for running) should not be worn.

Another important rule about running in the heat is that your head should be covered. A light-colored cap protects the head from overheating, and if it is regularly moistened with water, the cooling effect increases.

When is the best time to run in summer to avoid overheating?

The maximum air temperature in summer days, as a rule, is observed in the daytime hours, and in the morning, before dawn and the first 1.5-2 hours after sunrise, it is not so hot. Evening coolness comes when the sun slopes closer to the horizon. Until your body has adapted to the heat, it is better to shift your jogging to the early morning or late evening hours.

Whether running in hot weather is effective for weight loss

In short – no, it is not effective. Loss of 2 kg after an hour and a half of running in the heat is a loss of 2 liters of water. It will be replenished in the next few hours, and the weight will return to the original value. Trying to limit water intake after physical activity does not help either – chronic dehydration is bad for health and appearance, but it does not help to reduce body weight.