The Role of the Immune System in Sports Performance
The immune system is our body’s defence system against external elements such as viruses, bacteria, and fungi.
Footballers lose water every day, mostly in the form of sweat, urine, and respiration. They also ingest water in their food and drink. But in very hot temperatures, the amount of water in the body is not constant, which may cause alterations in cardiovascular function and to the regulation of body temperature, thus affecting performance, their skills and dexterity.
This process of losing body water is called dehydration, due to which acute or chronic dehydration, called hypohydration, occurs.
Drinks that contain carbohydrates and salts are ideal for hydrating athletes because they also provide electrolytes, which are substances that produce a positive or negative charge when dissolved in water. They are present in the blood and other bodily fluids and affect different functions, such as muscle activity.
The brain can also be affected by a lack of fluid, with lower cognitive performance and poorer reflexes and coordination, which can prove crucial in the final minutes of a match. So, when the body becomes dehydrated, body temperature rises. This information is processed by the hypothalamus, which triggers different responses such as the release of hormones.
The most common electrolytes are calcium, fluorine, magnesium, phosphorus, potassium and sodium, the latter being the most common. All these elements can be lost by sweating, so they must be replaced with liquids that contain them, which drinks like water do not.
A key aspect is the personalisation of each athlete’s hydration based on their physique, the intensity of the exercise they do and the environmental conditions. A simple method to tell you whether or not you need to drink is to look at the colour of your urine before you start a training session or a game. If it is light yellowish or transparent, hydration is adequate. If, however, the colour is darker, then you need to hydrate more.
Eating fruits and vegetables throughout the day increases hydration, while a protein-based diet causes dehydration. It is important to identify each player’s type of diet and fluid intake, because muscles have a tendency to tear when dehydrated.
In games that allow them, good use should be made of hydration breaks, especially in hot conditions. Players should drink a small amount of liquid every ten minutes or so. They should not drink much, to prevent liquid from accumulating in the stomach and causing gastrointestinal problems.
It is also a good idea to weigh yourself before and after exercising, to know how much fluid has been lost. It is advisable for fluids to be replaced within an hour or hour and a half after doing sport. The amount must be 150% of what has been lost: if an athlete has lost a kilogram of weight, then a litre and a half of liquid needs to be drunk.
Liquids can be replaced solely with water. But, as mentioned earlier, it is better to rehydrate with sports drinks because they contain glucose, carbohydrates and salts in different formulations, which means they can be personalised depending on the amount of exercise and the intensity of the heat. They can be consumed bottled or prepared at home, adding 2/3 parts of water and a little salt to natural fruit juice.
It is essential to make personalised hydration a part of team sport strategy. This is done by conducting hydration and sweat tests on the players at the start of the season to assess their required amounts of drink and salts. As well as comparing weights before and after exercise, the amount of lost salt is measured using patches on the skin that analyse sweat.
Athletes who lose more sodium after games or training are advised to take a sports drink along with a packet of salts or a piece of a food containing salt, such as Parmesan cheese.
Pre-match hydration should become an automatic part of an athlete’s routine, taking small, regulated sips for the 60-90 minutes before exercise. It is important for them to learn about their fluid needs and ways to monitor their hydration status.
Finally, it is important to be clear about the difference between sports drinks and energy (or energising) drinks. Sports drinks contain water, salts and sugars for hydration, as well as carbohydrates that provide energy.
Energy drinks have those components, but also others like taurine, which are not recommended for playing football. Alcohol is also discouraged, because it causes dehydration by slowing down the body’s water-saving hormones and lengthening muscle recovery time.
An article published in The Orthopaedic Journal of Sports Medicine —in which members of the club’s medical services participated— now suggests to consider the detailed structure of the area affected, and treating the extracellular matrix as an essential player in the prognosis of the injury.