Why drinking water could stop you being tired

Staying hydrated should be very simple, really. The advice has been bandied around for years: drink eight glasses of water a day.

That’s not even one glass an hour. Again, not really that hard, is it? Or maybe, it is.

According to a recent survey by the Natural Hydration Council, a measly four per cent of doctors believe their patients knew how much water they should be consuming on a daily basis, and one in five patients are going to their GP with symptoms of dehydration.

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Of course, these symptoms – mainly tiredness and headaches – may sometimes be the result of a number of medical conditions. However, “a surprisingly common cause” is failing to drink enough water.

Mind you, in defence of the water-shy, perhaps meeting your H2O-guzzling needs is not quite as easy as it sounds; although NHS guidelines state “you should drink 1.2 litres [6-8] glasses of fluid every day”, they also accept amounts needed “can vary”.

Confused? Hopefully this guide will help.

Drink at least 2 litres a day

“There is currently no agreement on the amount of fluid you need on a daily basis,” explains GP Dr Sarah Brewer (DrSarahBrewer.com). But the guide of six to eight glasses is about right.

“The amount of water an adult loses, during an averagely active day, is around 2.5-3 litres,” Dr Brewer continues.

“This is mainly lost through the lungs as water vapour, through the skin as sweat, and through the kidneys as urine. To replace this amount, you ideally need to drink at least two litres of water per day, and that’s in addition to other fluids such as alcohol, tea, coffee and soft drinks.”

Drink more when you exercise

“When taking vigorous exercise, or visiting a hot country, however, you may need to drink twice this amount or more. Athletes in hot climates may lose as much as ten litres of fluid per day!”

Dr Brewer adds that the simple tip “for every 20 minutes of exercise you take during the day, your fluid intake should increase by a further 250ml” is a useful guide to 

Drink before you’re thirsty

Grabbing some liquid when you’re already gasping could be too little too late.

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“Although the body has mechanisms to help control fluid loss through the kidneys, by the time you feel thirsty, you are already significantly dehydrated,” says Dr Brewer.

“Drink fluids regularly throughout the day, rather than just drinking when you feel thirsty. Carry a bottle of water and sip regularly.”

Check your urine

“An early warning sign of dehydration is passing less urine than normal, which is darker in colour,” she adds. “Aim to drink sufficient fluid to maintain a normal volume of urine which is pale coloured.”

Know the benefits

Apart from staving off dehydration, keeping your fluid levels topped up has added 
bonuses too.

“Dehydration can affect exercise performance, even when you’re only moderately short of fluids [less than two per cent dehydrated], and this level of dehydration can occur during exercise itself as a result of sweating, even if you were sufficiently hydrated before.

“Good hydration is also important for healthy, glowing skin with good elasticity [known as turgor]. Dehydration promotes dryness and wrinkling, which has an ageing effect on your looks.”

Other sources

Hydration isn’t all about the water, of course. “Some foods are good sources of fluid, such as low-fat milk, soups, melons, cucumbers and other juicy fruit and vegetables.

“Herbal [non-caffeinated] teas are both refreshing and an excellent source of fluid that counts towards your total water intake. Iced mint, lemon and other herbal teas make a great summer drink.”

Warning signs

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Dehydration affects the way your cells work, upsetting the body’s balance of minerals (salts and sugar) and “leading to lack of energy, tiredness, poor concentration, reduced alertness, recurrent headaches and mood changes”.

Symptoms of mild dehydration include:

Mild dehydration may impact how you feel and function but is easy to remedy.

• Passing small amounts of urine, infrequently (less than three or four times a day)

• Dizziness or feeling light-headed

• Dry mouth, lips and eyes

Symptoms of severe dehydration include:

If dehydration is not addressed at the early symptoms, it can become a medical emergency. Seek treatment and advice if you notice any of the following symptoms.

• Feeling unusually tired or confused

• Very dry mouth and eyes that do not produce tears

• Not passing urine for eight hours

• Dry skin that sags slowly into position when pinched up

• Rapid heartbeat

• Blood in your stools or vomit

• Low blood pressure

• Irritability

• Sunken eyes

• A weak pulse

• Cool hands and feet

• Fits (seizures)

• A low level of consciousness