Drinks Guide For Effort
For a long time, it was believed that to make sport it had to drink, and still drink until more thirst. Reason: avoid dehydration and the poor performance that goes with it. But, is it really necessary to drink liters of water? And what should we drink?
Water, without bringing in any calories, is very important for our body and represents between 60 to 70% of body weight. This corresponds to about 45 liters of water for a person of 70 kg. The athlete who trains regularly has a greater volume of water in his body because he has more muscles and these contain 73.2% water versus 10% in the fat mass. Where is the water? 60% in our cells and 40% in the tissues in which the cells bathe: lymph and blood.
Water for cooling
When muscles require more energy during exercise, they release 70 to 75% of the energy mobilized as heat. This heat is mainly removed by a natural transfer of heat to the outside: convection. Water plays a secondary role in cooling the body, even if this role is real. So, if we do sport more sweat it is because of the increase in energy expenditure (the “boiler” works at full capacity) and not because of a lack of water. This is a sign that your body is working well!
What is composed of sweat? This depends on the environmental conditions, the intensity of the exercise, the level of acclimatization to the heat but also the condition of the sportsman. Sweat is composed of 99% water and sodium, potassium, calcium, magnesium, zinc, iron, manganese and vitamin C but this exact composition varies. For example, athletes trained and acclimated to heat excrete less sodium per liter of sweat (115 to 690 mg per liter) than trained and unacclimated athletes (920 to 2300 mg per liter).
Water needed to burn energy
The body of an athlete will use a lot of carbohydrates during the effort. Some athletes anticipate the increase in energy demand by their muscles and choose a diet high in carbohydrates. Now when muscle cells use carbohydrates stored in the body, some of the water that was trapped in the muscles is released. Specifically, for each gram of stored carbohydrate that the muscle uses, 2.7 g of water is lost. Water also plays a role in providing energy.
Water to evacuate waste
In a sporting event, the whole body starts to fight: the muscles need more energy, the lungs move to higher speed, the blood tries to satisfy the increased needs of all the organs. It is therefore logical that the waste is also more important. Water is essential for the body to get rid of its waste through perspiration, urine, stool and breathing. But beware: more water does not allow to eliminate better, it is simply to avoid the dehydration, situation during which our system of filtration works less well.
Thirst, a mechanism of high precision
In order to know when to drink, our bodies have a formidable mechanism: when changes in the sodium level or the amount of water in the plasma occur, receptors in the brain at the hypothalamus level will cause hormonal changes and Behavioral to avoid severe dehydration: the kidneys will better retain water and sodium and the feeling of thirst will trigger. Contrary to popular belief, the sensation of thirst is very reliable when it is not disturbed by external elements (taking certain drugs, diseases, age).
Humans have evolved as long-distance hunters. This gave us the ability to regulate our body temperature to the corus of a prolonged effort in full heat even with a lack of water. The man does not regulate his water balance instantly, it is a drinker with delay: the deficits in water and minerals are corrected to the following meals.
The need to drink “in prevention” seems therefore useless. On the other hand, it is better to drink as soon as one is thirsty, without waiting if one wishes to avoid the dehydration.
Drink enough to avoid dehydration
When you do not drink enough to compensate for water loss, you may be dehydrated. The heart has to work harder and the heat regulation mechanisms are outdated: the heart rate increases, blood pressure decreases and the body begins to “overheat”.
A mild water deficit of about 1% of body weight is enough, that is to say only 0.7 liters for a man of 70 kg, to decrease by 10% the performances: the sportsman can feel fatigue, Headaches, nausea, heaviness in the legs, shortness of breath … When moisturizing decreases by 2%, the athlete’s physical and intellectual performance is impaired. Increased dehydration increases the risk of kidney stones and coma. The risk of heart attack or heart defects also lurks when the athlete loses 6-10% of his initial weight due to dehydration.
Finally, an athlete who is repeatedly dehydrated may suffer from muscle, tendon and ligament pain. Its risks of breakdown and sprains are increased.
When the dehydration becomes too great, the blood volume decreases. The noble organs, the brain and the heart, no longer receive enough blood. To preserve them, the body seeks to increase circulation: it closes the vessels leading to less essential areas like the skin. The body temperature therefore continues to rise while the cooling mechanism, perspiration, is no longer effective. The difference between the heat produced and the heat evacuated is too great. This is the heat stroke! It can be fatal because our brain can not withstand a temperature above 41 ° C. But, generally the heat stroke occurs without being in a state of dehydration, it is simply the diffusion of the heat that did not have time to be done correctly.
The movement of the muscles is achieved by the contraction of fibers inside the muscle cells. The contraction is done by exchanges of ions, mainly potassium, sodium, magnesium and calcium ions. Dehydration can lead to an imbalance in the exchange of ions, especially via perspiration which causes us to lose a lot of sodium: cramps then manifest. It is the most frequent symptom to warn of poor hydration (in quantity or in quality – see below).
Dehydration may favor the development of tendon problems even if the exact reason is not well known.
Risk of drinking too much: dilutional hyponatremia
Hyponatremia corresponds to the decrease in the concentration of sodium in the plasma, that is to say the liquid part of the blood. It can occur when there is excess water over sodium. Excess water can reach 5% of the athlete’s initial weight. Drinking clear water or a weakly mineralized beverage throughout a single hour (water bottle) effort dilutes the blood. Your concentration of salt collapses, it is dilution hyponatremia.
How does hyponatremia come about? In endurance exercises, hyponatremia is the consequence of inappropriate behavior: either “voluntary” hyperhydration or the consumption of an inadequate drink that does not compensate for the losses of sodium caused by perspiration. The most affected are mainly the “less” performing athletes who do not monitor their intake during exercise and consume drinks that are too low in sodium. When the effort is very intense or very long, the risk of hyponatremia is greater.
Hyponatremia is not always accompanied by symptoms. If there are any, they are not specific: nausea, vomiting, dizziness, discomfort, confusion, agitation, fatigue, coordination disorders but the most frequent signal is the appearance of cramps. Then headaches and sweating of the feet and hands can become more and more important while the body temperature remains normal.
|Drink little but often|
|If the amount of water absorbed is too large, only a portion will actually be used and the rest will be sent directly (or almost!) Into the bladder. If you persevere in excessive hydration you risk hyperhydration which is more rapidly fatal than dehydration … The drink is less well accepted during physical exertion. A large volume of water, if it facilitates the gastric emptying, can indeed stomach disturb and impede the exercise. This is why it is necessary to drink an isotonic drink that digests more easily, in small quantities throughout the exercise. During exercise, it would seem that drinking 150 to 300 ml of water every 20 minutes would be a good average.|
What to drink?
They usually provide too little sodium to compensate for the losses caused by sweating. These are beverages to be reserved for short-term efforts.
They contain as much sodium as there are in the cells of our bodies. This will facilitate digestion (no concentration disorders between different media) and replace sodium losses caused by perspiration. An isotonic drink is therefore a first step towards a good drink of effort and performance. Count 500 to 700 mg of sodium per liter of drink.
They contain carbohydrates and electrolytes. During exercise, they give energy to the muscles, help maintain blood sugar levels and reduce the risk of dehydration or hyponatremia. This is a good choice for performance but not all contain the right amounts of minerals for endurance efforts.
It is best to sweeten your water if the exercise lasts more than 45 to 50 minutes or if it is intense. The optimal solution: take about 1 gram of carbohydrates per minute, ie 1 liter of a 6% carbohydrate drink per hour.
Beverages containing more than 8% of carbohydrates such as fruit juices, soft drinks, and some energy drinks (often containing 10-12%) are not recommended during exercise. In fact, they are much more concentrated than blood in substances other than water molecules. To dilute these substances, the water passes from the blood to the intestines and the very sweet drink “stays on your stomach” because of ionic imbalances. In the same way, avoid the table sugar in your drink: the large amount of fructose present will be able to swell you during the effort (to be tested however since each reacts differently). Choose dedicated powder preparations or make your own mix with glucose, maltodextrin or a similar sugar.
They are useful for great athletes to replenish the muscle stores of carbohydrates and repair the tissues. Long-lasting, high-intensity training depletes energy reserves even if you have an energy drink during exercise. It is therefore important to redo its stock of energy. These drinks are therefore useful after the efforts of ultra endurance.
Are energy drinks interesting?
Several studies have reported that taking energy drinks (Redbull type) during exercise may increase performance, but without being compared to exercise drinks (1). However, no study has reported a beneficial effect on strength and potency, since caffeine doses would not be high enough to increase neuromuscular performance. A 250 mL energy drink can contains 75 mg (and 11 g of sugar), while the optimal dose seems to be 200 mg. Moreover, they are far too acidifying, low in sodium, high in sugar, and are not composed of carbohydrate mixtures. They are therefore not recommended.
In addition, energy drinks are accused of causing (rarely) heart problems or even cardiac arrest (2).
Criteria for choosing a effort drink
Ideally, an effort drink should:
– be isotonic or hypotonic
– contain 60 to 80 g of carbohydrate per liter (6 to 8 g / 100 mL).
– contain carbohydrates in the form of sugar, glucose, fructose, possibly maltodextrin
– contain 500 to 700 mg of sodium per liter (not to exceed 1 g / L)
– have a neutral pH
Choose dedicated powder preparations or make your own mix with glucose, maltodextrin or a similar sugar. You can also prepare your stress drink with simple ingredients (fruit juice, sugar, salt).
How to Make Your Own Effort Drink
It is possible to make yourself an effort drink even without maltodextrin: a sugar-based effort drink (glucose + fructose) may be interesting even if a beverage of effort based on Mixture of maltodextrin and sugar is probably better.
As a reminder, an exercise drink should bring about 60 g of carbohydrates per hour during exercise. So, in summer if you drink one liter per hour, you will need to prepare a drink containing 60 g of carbohydrates. In winter, for example, if you drink 500 mL per hour, you will need to prepare a 120 g carbohydrate drink per liter.
To obtain a drink containing 60 g of carbohydrate with 500 to 700 mg of sodium: 30 g of glucose and 30 g of fructose per liter, you can:
– “cut” 500 mL of fruit juice (orange and apple juice contains 100 g of carbohydrate per liter) in 500 mL of water and add a pinch of salt (between ¼ and ⅓ teaspoon)
– dilute 60 g of syrup / sugar in 1 L of water with a pinch of salt
Are the effort drinks essential to being 100%?
It is possible that drinking this type of drink is not essential: eating carbohydrates in solid form and drinking water rich in sodium (St Yorre, Celitian Vichy) could be just as effective.
According to a 2010 study, the body of cyclists succeeded in oxidizing both the carbohydrates of liquid origin (effort drinks) and of solid origin (energy bar) (3).
In addition, a study published in 2012 showed that eating bananas instead of drinking exercise drinks did not seem to affect performance (4). However, no information was provided on possible digestive disorders caused by the ingestion of fibers during exercise.
In summary, each being unique, it is still best to test yourself different approaches in order to decide which one suits you best.