How our body reacts to heat during run time

Summer this year was hot, and the run is not so easily at high temperatures. If you are not used to the heat, the heart begins to race much earlier than the sweat veiled eyes, dry mouth and constantly thirsty. It is because of these unpleasant feelings, we try to run either at sunrise or after sunset, or even on the treadmill in the gym with air conditioning. However, there are ways to avoid all this and get the most use and enjoyment out jogging.

Lawrence Armstrong, heat researcher at the University of Connecticut, says that the human body is surprisingly easy to adapt to the heat, it is much easier than a cold or, for example, height.

In an article published in the January 2015 Comprehensive Physiology, Daniel Lieberman proposes that our adaptation to heat. Perhaps this is due to the fact that our ancestors were hunting on the African savannah in the afternoon, when all of the most dangerous predators were resting in the shade. Ever since people spread throughout the world, and even if we live in northern latitudes, in our genes still retained heat tolerance, and at the right moment, the body of this recall.

This does not mean that you can so simply pick up and go to the most solntsepok for a run, and the body has adjusted to himself. Despite the fact that we were born to run in the heat, some people are still not as well adapted to these conditions. It is therefore necessary to follow certain rules that will help you, even if you belong to the second type of people.

10-15 ° C

Most runners do not find it warm, and if they just walked, it would have been absolutely right. However, even such a low temperature will affect you during the long race.

In 2007, in an article in Medicine & Science in Sports & Exercise team led by physiologist Matthew Eli studied the performance of elite runners and those who are close to their level, at a temperature of 4 to 8 ° C. What they found was surprising that even at a temperature of 10-15 ° C performance somewhat decreased, that was comparable with approximately 1-2 minute deceleration to two of the ten elite athletes. For a three-hour races in men slowdown was 4-8 minutes. A recent survey of French National Institute of Sport and Physical Education of almost 2 million finishers runners showed that optimum temperature for men is professionals about 5 ° C.

There are several reasons. Firstly, in these studies, the temperature is measured only at the start. This means that the race, which began at 15 ° C, may end at 21 ° C.

Physiologically, exercise in the heat triggers a cascade of reactions that begins with the fact that not all of our muscles are working efficiently. In fact, about 80% of the energy generated by our muscles out of the body in the form of heat... In cold weather, it warms us, but when we begin to exercise, the body needs to get rid of this heat, and one such way is to sweat. This is very important because our blood makes the excess heat to the skin, through which it reaches the surface.

But our body is very large, the muscles too much, and the blood must then not only bring extra heat to the skin, but also to provide our muscles they need for oxygen. And in this battle always lose muscle. Even the weakest sweating is a sign that your muscles are already getting less oxygen, and their efficiency is reduced.

16-21 ° C

This temperature span many consider not so and the best for running. Calculator Run SMART Project calculated that at 20 ° C running at 10 km result deteriorates by 1.7% (slightly more than 6 seconds per mile). For runners it will be slowing down for 1-4 minutes.

However, some people find it much easier and better to run in hot weather than in cold weather. Your body begins to adapt to high temperature as soon as you start to run in the heat. Within a week, your blood plasma volume begins to expand. This can increase your weight by 0.5-1 kilogram, but it gives you the extra fluid and the ability to sweat without dehydration. it also allows you to continue to intensively cool the body, while not particularly reducing blood flow to the muscles.

The following adaptation: we begin to sweat during workouts much earlier and more abundant than at cool temperatures. Thus our body learns to anticipate the subsequent rise in temperature and takes proactive measures.

Sweat becomes less salty, as the body works to keep the sodium. Your heart rate gradually slowed down at each level of effort - it allows the heart to fully comply with every beat and pump a greater volume of blood. This is called a stroke volume, by which the heart is catching up more blood, not only for the muscles, but also for enhanced cooling of the body.

Moreover, even changing your perception of heat, that is, the temperature of the discharge "all I die" becomes simply "hot."

These changes occur within 14 days after the start of training in the heat. But hurry not to be, and you should start slowly, otherwise you really run the risk of overheating.

22-26 ° C

At this temperature, the elite marathon runners lose 3 minutes, and the rest - as much as 20 minutes, while women show themselves better than men. Perhaps this is due to the fact that women are usually smaller than men and their relationship "weight - surface" is more optimal, as a result of heat output into the environment more efficient.

The same goes for men. During Atlanta Olympics marathon men at 23 ° C and 90% relative humidity defeated South African runner Joshua Tugvane which weighed only 45 kg. Silver medalist of South Korea Lee Bong Ju weighed 56 kilograms.

The outcome affects not only the correlation between the heat and the size of the body marathoners. In laboratory experiments, carried out shortly before the Olympic Games in Athens in 2004, physiologist Tim Noack watched two groups of men who ran 8 kilometers on the treadmill. In one group of males weight not exceeding 50 kg, in another mean weight was 59 kg. When cool temperature conditions of these groups were almost equal, but as soon as the temperature in room raised to 35 ° C, the athletes were lighter faster by about 45 seconds per mile than their larger Colleagues. That is bigger than you, the more you will be exposed to heat. Based on this, you need to learn how to adjust your pace for the weather conditions.

27-32 ° C

At this temperature, sweating more passes from the discharge advantages discharge problems. When the sweat poured in streams, you lose more water than heat. You already start to run at full capacity, not only his body, but also physics just are the conditions under which no longer has matter how you sweat profusely, as sweat just do not have time to evaporate, to keep pace with the amount of heat that you generate. The only way out of this situation - the rate of deceleration, so if you want to get satisfactory results at high temperature, it will be necessary to make much more effort during exercise, gradually increasing pace.

32 ° C or higher

And here already begins the real heat! The key to running in such conditions - scrupulous thinking through everything that somehow can affect your performance, whether your pace or choice of clothing. You have to work hard over hydration by designing a specific plan to drink, and not to forget about isotonic. It is also worth to teach yourself to drink more fluids. Your limit will not exceed 1 liter per hour, but most people are not used to drink as much liquid for such short periods of time.

Even if you have decided to give himself an easy run 5 kilometers, which usually does not take with water, and the weather forecast shows a 27 ° C, better to take a small bottle of water.

Another interesting adaptation option - to start the sauna. Especially if you decide to take part in competitions in some tropical countries with hot and humid climate. For the preparation of elite athletes use special cameras in which simulate the weather conditions of the place in which competitions are held. But ordinary people this is not possible, so our output in this case - use of the sauna at least two weeks before the start of the race.

Instructions for running in hot weather

1. Remember: even if you think that the street is cool, your body is still warm, some of the blood volume goes to ensure that provide cooling and your muscles start to work less effectively, their portion will receive less oxygen. When the short run it can be ignored, but it is worth considering this factor during long races, as changes in tempo will become visible.

2. Try not to avoid exercise in the heat. Let your body adapts to these conditions. Your system will be more effective through a fairly short time (adaptation time to heat - 10-14 days), as will learn to anticipate an increase in temperature and will adapt to the new conditions.

3. When the temperature and humidity rise, it is better to slow down. Your productivity will remain at a high level despite the slower speeds.

4. If you have to participate in the competition in the heat, do not exercise in the last two days before the race and make sure that you're not overextended his body.

5. Properly restore their water supplies, using not only water, but also the isotonic, which will allow to resupply essential minerals, leaving your body through sweat. If you have a long race, it would be good to make a drinking schedule, set the timer and drink every time the alarm will sound.

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