The adult body is made up of approximately 70% water. The amount decreases with age and most of it is found in lean muscle tissue. However, important organs contain even more water: our brain is made up of 75% water, our lungs are made up of 80% water, and our kidneys and blood are made up of 83% water. How essential it is to our functioning is evidenced by the fact that a person can survive up to two weeks without food, but only 2-3 days without water.
Water - the basic component of living organisms.
The importance of water in the body
The adult body is made up of approximately 70% water. The amount decreases with age and most of it is found in lean muscle tissue. However, important organs contain even more water: our brain is made up of 75% water, our lungs are made up of 80% water, and our kidneys and blood are made up of 83% water. How essential it is to our functioning is evidenced by the fact that a person can survive up to two weeks without food, but only 2-3 days without water.
Water is needed by the body because it regulates the chemical processes and reactions of every living cell. If each cell is to replenish the reactions required to function with optimum speed, movement and endurance, the body must have adequate access to fluids. Some of the functions of water include:
- transporting proteins, amino acids, carbohydrates, vitamins, minerals and oxygen into cells.
- being part of the structure of chemical compounds in the body.
- aiding digestion and absorption of nutrients.
- helping to repair and replace old tissues.
- helping to flush the system of toxic waste.
- helping to maintain a constant body temperature by providing sweat for cooling and blood circulation for heating.
- lubricating and cushioning joints and body tissues.
The importance of water in the body
The adult body is made up of approximately 70% water. The amount decreases with age and most of it is found in lean muscle tissue. However, important organs contain even more water: our brain is made up of 75% water, our lungs are made up of 80% water, and our kidneys and blood are made up of 83% water. How essential it is to our functioning is evidenced by the fact that a person can survive up to two weeks without food, but only 2-3 days without water.
Water is needed by the body because it regulates the chemical processes and reactions of every living cell. If each cell is to replenish the reactions required to function with optimum speed, movement and endurance, the body must have adequate access to fluids. Some of the functions of water include:
- transporting proteins, amino acids, carbohydrates, vitamins, minerals and oxygen into cells.
- being part of the structure of chemical compounds in the body.
- aiding digestion and absorption of nutrients.
- helping to repair and replace old tissues.
- helping to flush the system of toxic waste.
- helping to maintain a constant body temperature by providing sweat for cooling and blood circulation for heating.
- lubricating and cushioning joints and body tissues.
Water balance
Daily requirement. We usually hear that we should drink 1.5-2 litres of water per day. However, it is important to note that every body is different and factors such as gender, age, body weight, ambient temperature and physical activity are of great importance in determining daily water requirements. It is assumed that an adult doing moderate physical activity at a comfortable body temperature should on average drink about 35ml of water per kilogram of body weight per day. The minimum daily water intake for a 70kg person is then 2450ml. This requirement obviously increases as external conditions change.
Drinking water.
The water needed by the body comes from a variety of sources and is supplied by eating, drinking and metabolism. In addition to water itself, drinks such as milk, sports drinks (electrolytes) and juices contain large amounts of water. Other foods also contain rich stores of water. Fresh fruit and vegetables usually contain a lot of water (some as much as 95 per cent), while protein foods such as beef and eggs can contain up to 50 per cent water. Water is also released into the body when food is broken down and through metabolism.
Properties of water.
To ensure proper hydration, the amount of fluid lost must not exceed the amount taken in. The body can lose up to one and a half litres of water per day through the normal processes of sweating, breathing and excretion. During prolonged physical activity, water losses increase due to increased respiration and sweating. In fact, during strenuous and prolonged activity, we can lose between 2 and 4 litres of sweat in just one hour! The digestive system, on the other hand, can only absorb about 1 litre of fluid per hour, so we should consume fluids before, during and after exercise to replenish fluid loss and minimize dehydration.
Water loss on hot, humid days
High temperatures increase the rate of water loss through sweating. Exercise in hot, humid climates poses a further problem: the body's ability to sweat efficiently is reduced because the sweat on the skin evaporates less well. The air is already filled with moisture, making it more difficult for sweat to evaporate. As a result, the body cannot cool itself properly and the internal body temperature can rise to dangerous levels.
Other factors can increase the rate of fluid loss. These should be avoided or minimised to stop the onset of rapid dehydration:
- clothing that is too thick, waterproof clothing;
- exertion in environmental conditions to which the person is not accustomed;
- intensywne poziomy promieniowania słonecznego (duże nasłonecznienie).
- intense levels of sunlight (high insolation);
- increased intensity of exertion;
- not consuming fluids every 15-20 minutes during exercise (we should drink even if we do not feel thirsty).
We need to consider these factors that increase the rate of fluid loss and be particularly careful when exercising on sunny, hot and humid days. These combined factors represent the most dangerous environmental conditions. They promote rapid dehydration and rapidly raise internal body temperature.
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