Up to 60 percent of the human adult body is water, a highly valuable substance that is used to manufacture neurotransmitters in the brain, regulate body temperature, and deliver oxygen throughout the body among countless other jobs. Water serves a number of essential functions that are vital to the life of every cell in the human body, from the initial stages of cell production through to body regulation, protection, and waste management. Each and every day, we must consume a certain amount of water in order to survive - but just how much do we need?
Water is needed by every part of the human body, from our seemingly dry bones through to our heart, lungs, and brain. According to H.H. Mitchell from the Journal of Biological Chemistry, the lungs are composed of 83 percent water, the muscles and kidneys are 79 percent water, the brain and heart are 73 percent water, the skin contains 64 percent water, and even the bones are 31 percent water. Every single system in the body is reliant on water, from digestion and respiration through to lubrication, cell building, and waste management.
Dietary guidelines around the world often don't recommend a specific measurement of water consumption, with the amount people need dependent on age, sex, weight, temperature, and physical activity. The most famous guide comes from a 1945 recommendation for the Food and Nutrition Board of the United States National Research Council, which stated "A suitable allowance of water for adults is 2.5 litres daily in most instances." While we are often told to drink ten or eight glasses of water a day in order to meet this objective, the recommendation also said that "most of this quantity is in prepared foods," including beverages such as juice and tea.
Because our body can't store water, we need fresh supplies every day to make up for natural losses from the lungs, skin, and waste systems. While it's important to listen to your body and drink when you're feeling thirsty, it's even more important to drink regularly throughout the day to avoid feeling thirsty and getting dehydrated. Common signs of dehydration include dry lips and mouth, dark coloured urine, fatigue, flushed skin, and dizziness. According to Anna Debenham, accredited practising dietitian, "Severe dehydration can result in: low blood pressure with a rapid heartbeat, fever, lack of energy, delirium, unconsciousness, severe diarrhoea and/or vomiting, and inability to keep fluids down."
Even though it doesn't makes sense to recommend an exact quantity of water for everyone, as a general rule women are advised to drink 2.1 litres per day and men advised to drink 2.6 litres. It's also important to drink more water during and after exercise and in hot weather conditions. Certain demographics of people need to drink more water than others, with babies, kids, and pregnant women often needing more water than the general population. Having a water bottle with you at all times is the best way to keep up your fluid intake, with fruits, veggies, yoghurts, and soups also a great way to keep your body wet. While coffee, tea, and alcoholic drinks can help to increase your water intake, these drinks can also lead to dehydration when consumed in excess.
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