4 1℃ What happens when you brush a PB for half a horse?

High temperature VS running: the unbearable high temperature for runners? How to run when running in hot weather?

When facing 30℃ or even 40℃ in summer, many friends cried and said, "The same heart rate, the pace dropped directly for a minute, and I couldn't bear to look straight!" Many runners change their morning running into fun running and choose to hide in the hot sun.

How to run when running in hot weather? What effect does ambient temperature have on human body? How to avoid danger?

Those misfortunes warned of the danger of high-temperature exercise.

Let's look at several related cases first:

A unit long-distance running sports meeting made 25-year-old Mr. Hong (a pseudonym) run out of heatstroke shock and almost entered the "ghost gate". 15 On the morning of May 9, 2005, Mr. Hong, 25, participated in a 10 km long-distance running sports meeting. Near the finish line, Mr. Hong suddenly fell into a coma and even suffered from acute liver and kidney failure. He was sent to the emergency department of the Fourth Hospital of Changsha by ambulance for rescue. At present, Mr. Hong is receiving further rehabilitation treatment in the emergency ICU.

20 1 8 at 9 o'clock in the evening, a 28-year-old man fainted while running near Huace Central City, Longgang River, Shenzhen, and died after being rescued on the spot on 120.

On the morning of May 26th, 20 18, a young man suddenly fell to the ground while running on the main road around Xiamen. Although passers-by helped to dial 120 in time, the man died after being taken to the hospital because he did not get effective cardiopulmonary resuscitation before the medical staff arrived.

How do you feel when you see these shocking cases? Does running in summer make you awe?

In fact, there are countless similar examples every year. All runners in the world are family members, and these bad news often cause heated discussion in major runners. While everyone is sorry, they are also thinking about how to keep this warning line of life safety when running.

Second, high-temperature exercise, most afraid of sports heatstroke.

Definition hint

Fever: It often occurs in high temperature and high humidity environment. It is a disease characterized by disorder of thermoregulation center, sweat gland failure and excessive loss of water and electrolyte.

Exercise-induced heatstroke: The heat generated by muscle exercise exceeds the heat that can be emitted by the body, which leads to overheating of athletes' physical fitness. Common in young physical exercisers, soldiers, marathon athletes, super-horse athletes, triathletes and so on.

People who have lived in the city for a long time are becoming more and more unfamiliar with heatstroke, as if heatstroke has nothing to do with us. Indeed, air conditioning, as one of the "greatest" inventions of modern civilization, brings us coolness, and with the change of social division of labor, people do not need to expect to work at high temperature for a long time. But this brings us a lack of understanding and attention to the symptoms of heatstroke. At the same time, living in an air-conditioned room for a long time weakens our body temperature regulation mechanism and makes it easier to get heatstroke when going out.

"heatstroke" belongs to severe heatstroke in the classification of heatstroke, and the mortality rate is high. Once it happens, it is big news, which can often be seen in newspapers.

In fact, in addition to heatstroke, less fatal diseases such as heat spasm, heat collapse and mild heatstroke should be popularized and attracted the attention of runners. They are warning signals when the body can't adapt to the environment and adjust itself. Only by grasping body signals sensitively and timely can we nip in the bud and keep the bottom line of health and safety.

Exercise-induced heatstroke is also heatstroke in essence. It is unique in that when we are running, we usually focus on places other than our bodies, such as roadside scenery, music in our ears, dinner tonight and so on. , and often ignore the change of ontology feeling. Coupled with the strong "willpower" unique to runners, discomfort is usually ignored.

When we are exercising, a lot of heat energy will be generated in the process of ATP energy supply in the body, which will lead to the increase of the temperature in the body and make people feel "hot", but usually we can't tell the subtle difference between the heat level and the heat dissipation.

Therefore, we need to have a clear understanding of the symptoms of heatstroke, and when running in summer, we should pay more attention to the changes of body feelings, respect body signals, and don't try to control everything with willpower.

In Wikipedia's "heatstroke" entry, it is classified like this:

Heat loss: wake up in direct sunlight for a long time. Dehydration caused by sweating, peripheral blood vessels dilate, and systemic blood circulation decreases, leading to sudden disappearance of consciousness. The body temperature is higher than usual, obviously sweating, and the pulse is slow. Transfusion and cooling therapy are recommended.

Thermal fatigue: when the supply of water and salt can't keep up with a lot of sweating, dehydration symptoms will occur. There are various symptoms, such as rectal temperature rising to 39℃, cold skin, obvious sweating and so on. Transfusion and cooling therapy are recommended.

Heat spasm: occurs when water, salt and minerals are insufficient after sweating a lot, and painful spasm and stiffness suddenly appear. Body temperature is higher than usual, obviously sweating. It is recommended to inject saline through the mouth.

Heatstroke: It occurs when the warm center of hypothalamus is disturbed and the thermoregulation function is lost. Have a high degree of consciousness disorder, the body temperature rises above 40℃, sweating is not obvious and the skin is dry. It is recommended to be admitted to the hospital urgently and have hypothermia treatment as soon as possible.

You will find that heatstroke is not only a physical discomfort, but also a neurological loss of control. Moreover, not all heatstroke will feel very hot and sweat a lot, so we should fully understand its performance.

Here, in the form of a table, the above symptoms of heatstroke are summarized for collection:

Third, prevent heatstroke. Many people will say that I just feel very hot and sweat a lot when running in summer. I have never suffered from heatstroke, so don't worry too much. But in fact, it's very likely that you have a harbinger of heatstroke, but you don't realize it yourself, which basically stems from your ignorance of the concept.

When we exercise, there are many kinds of chemical reactions in the human body, which not only produce kinetic energy, but also heat energy, the latter is mostly, accounting for about 70% of the total energy. There is no other use except to raise body temperature. In other words, a runner who runs more economically means that his heat energy ratio will be lower. )

According to the laws of nature, the human body temperature must be kept within the range of 35℃-42℃ to ensure the normal operation of the body. Therefore, our body has a set of heat dissipation and body temperature control mechanisms, such as radiation, conduction, convection and evaporation. For example, the brain usually gives instructions to stop exercise before the body temperature reaches 4 1℃.

How much the human body's regulatory mechanism can play depends on the external environment. When the temperature and humidity are too high, the heat dissipation mechanism will face greater challenges. What we can do is to help the body cool down and dissipate heat better, reduce the intensity of exercise in time, and don't insist.

1 to prevent excessive dehydration.

The most obvious feature of summer sports is sweating like rain, especially psychedelic drugs. After running, the whole person can raise fish in his shoes as if he had fished it out of the West Lake.

Running in summer is bound to lose more water. Generally speaking, when we exercise vigorously for several hours in a hot environment, a lot of sweating will lead to dehydration. Every time we excrete 1 l sweat, the exercise heart rate will increase by 8 times, and the cardiac output will decrease by 1L/min. At this time, the body temperature and heart rate will increase significantly, and the cardiac output will decrease.

Therefore, when exercising in hot summer, especially long-distance high-intensity training, we should pay attention to the feeling of the body and replenish more water. In particular, runners with cardiogenic heart disease must slow down, pay attention to hydration, and pay attention to the high heart rate during running. They should not be "willful" at their usual speed.

It should be noted here that some weight-loss runners will wear airtight clothes or wrap plastic wrap to run in pursuit of "fat burning effect", because many people think that the more they sweat, the more uncomfortable they are during training and the more they can lose weight. But in fact, this is a dangerous and meaningless thing. In doing so, the only effect is to make you lose more water (even go into dehydration). Even if you stand on the weighing scale after running and find that the figures are amazing, all you need is water, and you will soon make up for it.

According to research, if you really want to lose 1kg during exercise, you need to consume 37500KJ of heat, which is equivalent to running 160km. So, you can imagine how much "water" you lose when you run 1kg once. In running, the energy you consume is only related to the time and distance you run. If you want to lose weight, all you have to do is run as far and as long as possible under the premise of safety.

2. Be alert to the precursor of heatstroke

Severe heatstroke symptoms can't be achieved overnight, and most of them are because you ignore the early signs of discomfort. When you start to have symptoms such as headache, dizziness, general weakness, palpitation, inattention and uncoordinated movements. In addition to sweating a lot, it means that your body function is abnormal and you need to pay attention. It is a sign of heatstroke.

If you don't stop exercising immediately at this time and cool down and replenish water, you may enter mild heatstroke, which is characterized by flushing, sweating a lot and rapid pulse. Your body temperature will rise above 38℃.

If this happens when you are running, don't think it is normal. You should stop to rest immediately, cool down and replenish water, so as to stay green and not be afraid of burning without firewood.

3. Pay attention to the humidity change

I believe that many people hate humid and sultry weather, and this instinctive reaction is not unreasonable. Compared with pure high temperature weather, exercise in hot and humid weather is indeed more "terrible".

In a quiet state, the body surface temperature of the human body is about 33℃, and at this time, it mainly relies on air convection to dissipate heat. When the temperature is higher than 33℃, the human body will not be effectively cooled by air convection. At this time, we will start sweating-1kg of sweat will evaporate and take away the heat of the human body 1092-2520KJ.

However, sweating is not everything, and its heat dissipation effect is limited by air humidity. If the humidity is too high, the air can't absorb more water, sweat can't evaporate, and it can only be excreted, so naturally it can't play a role in heat dissipation.

In other words, your sweating and heat dissipation function depends on the external environment, not that the more you sweat, the better your heat dissipation. Therefore, summer running needs to pay attention to the weather forecast in advance, at the same time pay attention to the temperature and humidity indicators, and actively reduce the intensity of exercise in hot and humid climate.

Especially for heavy runners, it is more necessary to control their exercise intensity in hot and humid weather. According to research, the lighter a runner is, the less heat he generates, and the more he can maintain his speed in a hot and humid environment. The heavier a runner is, the more heat he generates. When the temperature and humidity of the external environment are too high, it will be difficult to maintain the thermal balance in the body, which will lead to an increase in heart rate.

label

For runners, walking is necessary whether it is cold winter or hot summer. Summer is there. It doesn't come or go, and it doesn't give in at all. What we can do is to establish a good relationship with the environment in order to run happily.

We love running because we hope it can bring us healthy and strong physical quality, and we also hope to get inner enrichment in challenging ourselves. All this must be based on the fact that running is a pleasant and harmless thing.

Running in hot weather, the body temperature rises, and the cooling load is heavy, which easily leads to fatigue, which in turn leads to the decline of sports performance. This is an inevitable process determined by the laws of nature and the result of the operation of the body's self-protection mechanism. We need to understand and accept its existence. If you try to resist, or ignore the existence of rules, you will go to the high-risk red line.

In the face of hot weather, we can't just surrender. The human body has a smart regulation mechanism and can adapt to the heat through 7- 14 days of training.