How much water do you really need to drink a day?
"Eight glasses a day" — myth or rule? What your water needs depend on and how to tell you are drinking enough.
Water is involved in almost every process in the body: it regulates body temperature, carries nutrients and helps the kidneys and joints work. Even slight dehydration — a loss of 1–2% of body weight — can show up as fatigue, headache and poorer concentration.
How much water should you drink a day?
The UK's NHS advises aiming for 6–8 glasses (about 1.5–2 litres) of fluid a day. That is not only water: tea, coffee, milk and soups count too. Part of our fluid comes from food — especially vegetables and fruit.
When does your body need more water?
- In hot weather and on planes — the air is dry and losses increase.
- During exercise — drink before, during and after.
- In the mountains and on active trips (see "Active holidays").
- When you have a cold or a fever.
How can you tell you are drinking enough water?
The simplest guide is urine colour: pale straw means all is well, dark means it is time to drink. Thirst is a signal too, but it weakens in older people, so they are better off drinking on a schedule: a glass in the morning, with every meal and in between.
Which drinks are best avoided?
Sugary fizzy drinks and juices give lots of sugar without making you feel full. Energy drinks and lots of coffee throughout the day can interfere with sleep. The best choice is plain water, with lemon, mint or berries if you like.
By the way, drinking enough water is part of LifeWave's recommendations for anyone using X39 patches (more in "What X39 is and how to wear it"). And for the home the company offers the LifeWave X₂O system: it filters tap water, enriches it with hydrogen and infuses it with light. The filters are replaced about every six months — as a bundle or separately: primary and secondary.