Water – the elixir of life

Did you know that our lungs are made up of 83 per cent water? To ensure we hydrate our bodies to their full potential Nutritionist Dr Emma Derbyshire explains why water is essential for our health and wellbeing…

Water is essential for life. It accounts for about 65 per cent of our body weight and performs crucial roles such as carrying nutrients and waste products between our major organs, helping regulate body temperature, lubricating our moving parts, and acting as a shock absorber.

The human body works hard to maintain optimal hydration by using hormones to control how much we urinate and giving our brains signals to tell us that we are thirsty. And because our brains are 75-85 per cent water, poor hydration can have an adverse effect on how our brains function.

On average, we take in and excrete around three litres of fluid a day but dehydration causes the following symptoms:

• Increased thirst

• Dry, sticky mouth

• Tiredness

• Reduced concentration

• Headache

• Muscle tiredness

• Decreased urine output

• Dark yellow or brown urine

• Dizziness or light-headedness In babies and young children, even mild dehydration can cause symptoms such as confusion, irritability and tiredness.

Young children are less effective at regulating their temperatures, and have a larger surface-to-weight ratio than adults so are less tolerant to fluid losses such as through vomiting or diarrhoea.

Our bodies are constantly fluctuating between different states of hydration. When our water intake matches our bodies’ requirements, this is described as optimal hydration.

Scientists, sports and health professionals sometimes measure hydration by measuring changes in body weight. Dehydration can be defined as a two to three per cent drop in body weight in a typical warm environment.

We are the greatest at risk of dehydration when we are too hot or too dry, have limited access to water, or need more water than usual. Warm or dry environments, such as centrally-heated homes or air-conditioned offices increase our need for fluid. We can lose additional fluid through sweating (due to exercise or hot climates), or by suffering vomiting and diarrhoea.

Like vitamins and minerals, our fluid requirements are individual and depend on factors such as body weight/size, physical activity and the temperature of our environment. However, a number of different expert bodies have made recommendations for fluid and these are a good starting point.

The Food Standards Agency has based its guidance on glasses of fluid a day (i.e. over and above any fluid that we may have from foods). Adults are recommended to drink six to eight glasses a day to prevent dehydration (around 1.2 litres).

Experts recognise that a regular intake of water is vital for maintaining good health. And optimal hydration can even help prevent some common conditions, such as constipation, urinary tract infections, gallstones and glaucoma.

It may also lower the risk of stroke and asthma. Emerging evidence also suggests that adequate hydration could play a role in the prevention of some cancers, including bladder and colon cancer.

Natural Hydration Council


How much water is in our body?

Brain 75 per cent

Lungs 83 per cent

Liver 71 per cent

Skin 64 per cent

Bone 31 per cent

Heart 73 per cent

Muscles 79 per cent

Kidneys 79 per cent

Average water content is 65 per cent in adults


Hangover v hydration (or partying without pain)

Ten tips for healthy hydration

1. Make sure you always have access to water, even when out and about

2. Bottled water is handy when you’re at work or on the move

3. Drink an amount of fluid that is right for you this should be adapted to your own needs

4. Drink water at regular intervals throughout the day

5. Quench your thirst with water first before going on to enjoy other beverages such as tea, coffee, squash and fruit juices

6. Remember that water-containing foods can contribute to your daily fluid intake, for example yoghurt, soups, stews, fruit and vegetables

7. Alcohol is dehydrating and should be balanced with plenty of non-alcoholic fluids, such as water.

8. Excessive amounts of caffeine can also be dehydrating

9. Remember to drink more when you exercise or spending time in hot environments

10. Young children and older people can dehydrate quickly so offer them drinks on a regular basis.


* Dr Emma Derbyshire is Consultant to the Natural Hydration Council for more information 


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