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StillnessHydration fact

Water makes up about 60% of an adult's body weight. The body needs it to control its temperature, keep blood flowing, digest food and keep organs working. When lost fluid is not replaced, thirst can come with tiredness, headache, dizziness and poorer concentration.

Harvard T.H. Chan School of Public Health

Health

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Every day we lose water in urine, in sweat and even in our breath, and more in hot weather or during exercise. About a fifth of what we take in comes from food, especially fruit and vegetables, and the rest from drinks. The NHS suggests 6 to 8 glasses of fluid a day, and water, lower-fat milk, tea and coffee all count. Thirst is the body's alarm: when the blood becomes slightly too concentrated, sensors in the hypothalamus, a small region at the base of the brain, trigger the urge to drink. This alarm weakens with age, which is one reason older people become dehydrated more easily. A simple check is the colour of urine: the NHS advises drinking enough to keep it a clear pale yellow, and darker urine is a sign to drink more.

Türkçe oku
Yetişkin bir insanın vücut ağırlığının yaklaşık %60'ı sudur. Vücudun ısısını dengelemek, kan dolaşımını sürdürmek, besinleri sindirmek ve organlarını çalıştırmak için suya ihtiyacı vardır. Kaybedilen sıvı yerine konmazsa susamanın yanı sıra yorgunluk, baş ağrısı, baş dönmesi ve dikkat dağınıklığı da görülebilir.

Her gün idrarla, terle, hatta nefesle su kaybederiz; sıcak havada ya da egzersiz sırasında bu kayıp artar. Aldığımız suyun yaklaşık beşte biri besinlerden, özellikle meyve ve sebzeden, geri kalanı içeceklerden gelir. Birleşik Krallık'ın ulusal sağlık hizmeti NHS günde 6–8 bardak sıvı içmeyi önerir; su, yağı azaltılmış süt, çay ve kahve de buna dâhildir. Susamak, vücudun alarm zilidir: Kan biraz fazla yoğunlaştığında, beynin tabanındaki küçük bir bölge olan hipotalamustaki algılayıcılar su içme isteğini tetikler. Susama hissi yaşla birlikte zayıflar; yaşlıların daha kolay susuz kalmasının bir nedeni de budur. Basit bir ölçü idrarın rengidir: NHS, idrarın berrak ve açık sarı kalmasına yetecek kadar sıvı içmeyi önerir; renk koyulaşıyorsa daha fazla içmek gerekir.

Sources and further reading

Background reading: Dehydration
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He who has health has hope, and he who has hope has everything.

English quotation books have called this an “Arabian proverb” since at least the 1860s; Tryon Edwards's A Dictionary of Thoughts (1891) is one, but these books give no Arabic original, so the label is best taken loosely. The idea is widely shared: good health gives people the strength to plan and to recover from setbacks. Turkish says “Her şeyin başı sağlık”, health comes first, and when a glass breaks people say “Sağlık olsun”: never mind, as long as everyone is well.

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In studies that compare meals with the same number of calories, the higher-protein version usually keeps people satisfied for longer, although the effect is modest. One reason is that protein prompts the gut to release more of the hormone PYY, which tells the brain that food has arrived; a 2006 study led by Rachel Batterham at University College London found the strongest PYY response after high-protein meals. Another is that the body works harder to process protein: a 2004 review by the Maastricht University physiologist Klaas Westerterp reports that digesting and using it burns 20 to 30% of its calories, against 5 to 10% for carbohydrate and up to 3% for fat. UK guidance puts adults' needs at about 0.75 g of protein per kilogram of body weight a day, around 45 g for women and 56 g for men, and average intakes are well above that.

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