Are you getting enough?
…water, I mean?

Water is the most important substance (along with air) on the planet. The sea was the birthplace of life on Earth and all known life depends on it to a greater or lesser extent. For us humans (just in case you were wondering if a thousand monkeys had written this), water makes up a large proportion of our bodies’ make-up and after the air we breathe, is the substance most vital to our survival.

But it’s not just survival we’re talking about – it’s staying healthy. The water in your body is there for a reason (several reasons actually) and it’s important that we maintain the correct levels. So what exactly does water do for us? As it turns out, even more than the Romans!

Water helps eliminate waste, especially through urine and sweat, helps regulate the body’s temperature, it carries nutrients to cells, aids in the maintenance of tissue structure, provides lubrication and is a medium for many of the chemical processes which occur in your body, including digestion of food; to the extent that some survival experts recommend eating little or nothing when lack of water is the main threat. However, as we get 20% of our fluids from food, you have to take the type of food into account. Most vegetables, for example, have a relatively high water content.

Hence, the first of many contradictions among people who profess to be experts. What follows is my attempt at answering some of the most common questions about water for health.

Contradictions about water for health

Unfortunately, as with most things, even the opinion of experts is far from unanimous and, for every person who claims evidence on one side, someone else will point to other research that contradicts it. Most sources will say you should drink 8 (x 8oz) glasses of water a day, while some experts have called that a myth. Opinions on whether tea, coffee, beer and other drinks count are split down the middle.

The best we can do is to gather the most commonly held beliefs of current scientific thinking and point out the range of difference where evidence is lacking.

De-hydration – Problems of too little water

Personally, I’m fortunate to have been mostly very healthy so far (touch wood) but I am prone to get headaches now and then and, after trying to identify the cause from the ‘usual suspects’, I have found that, in fact, the main culprit for me seems to be dehydration. And I don’t just mean from hangovers! The latter, though, are caused by a shortage of water in the body, which tries to take it from the brain, leading to a severe headache.

I suspect that many other people suffer similar problems to me and don’t even realise it. Other symptoms include a dry mouth, tiredness, lack of concentration, confusion and irritability. Excessive exposure to heat , especially in humid conditions, can lead to heat stroke because increased humidity prevents sweat evaporating from the skin to cool the body. More serious problems of severe dehydration include constipation and long term it can lead to kidney stones, blood clots, heart attack or stroke, as it can increase the viscosity of blood.

How much water should we drink?

The only correct answer is “enough, but not too much”!
What this translates to obviously depends on a number of factors, including where you live, body mass and age but varies between 1.5 and 3 litres per day in a temperate climate. The oft-quoted amount is 64 oz – or 8 glasses per day.

However, nobody seems to know where this figure emanated from, or whether it includes the 20% of fluid we get from food. Some experts think this is an exaggeration and that six glasses would be sufficient under normal circumstances. However it depends so much on other factors that it seems to me a moot point.

Children, depending on age, should drink about less than adults but slightly more in relation to their body weight.

If you’re doing heavy exercise, especially in hot weather, or if you have a dehydrating illness such as diarrhoea or vomiting, then you should drink more. Athletes under such circumstances can lose 10 litres a day.

Oh, and if you’re crossing the sahara desert, take a LOT more. Some medicines, such as diuretics and others can also increase dehydration. There is some evidence that elderly people might drink – and need – less than younger people, but whether that is down to less activity is unclear.

How can I tell if I’m getting the right amount of fluid?

It’s easy to think that the answer is simple – when you get thirsty, have a drink. And that is exactly what some people say we should do. Certainly, if you are thirsty, you should drink, but some people only notice thirst when they’re already slightly dehydrated. This can be due to lack of sensitivity to their body’s requests or just due to concentration on other things, at work, for example.

So as a way of maintaining a good water balance, rather than topping it up afterwards, it can be a bit late.
Adding to the argument for drinking water regularly rather than relying on thirst is the fact that there may be a slightly higher risk of dehydration in elderly people due to a reduced thirst response and, perhaps, a reluctance to drink in the evening in case it means a visit to the bathroom in the night.

Another way of monitoring your hydration level is by the  frequency or toilet visits and colour of your urine.
Pale straw colour = good;
Darker yellow probably indicates that you should drink more.

Mild dehydration should be remedied fairly quickly by drinking water, but anyone suffering from the the more severe symptoms should consult their doctor.

Can you drink too much water?

Excessive consumption of anything can be poisonous so it is possible, although unlikely for most people under normal circumstances.

Water intoxication can mean the kidneys are unable to cope, which can lead to swelling of the brain. Symptoms, ironically, are not unlike those for dehydration – including headaches, confusion and nausea. In extreme cases, it can lead to coma and, in rare cases, ultimately prove fatal.

Drinking excessive amounts of water can be the caused by illnesses which affect the body’s water balance, such as kidney failure or cirrhosis of the liver, and by some drugs, including illegal ones such as ecstasy.  The biggest risks, though, are probably from water drinking contests, or from athletes who drink large amounts to rehydrate but do not sufficiently replenish electrolytes (minerals such as sodium, potassium, calcium etc.)

Over-hydration can lead to Hyponatremia, a dangerously low level of Sodium, which helps amongst other things to help transport water around the body.

Aa well as older people possibly having an increased risk of dehydration (see above), it is also possible that the risk of over-hydration is greater in some elderly people due to a lessened movement of water through the system.

Is there a best time to drink water?

It is generally thought that drinking frequently throughout the day is better than trying to stock up like a car’s fuel tank, or, worse still, make up for a deficiency later on. Drinking in the morning on waking can be a good idea as you may not have drunk anything for eight hours. Likewise, drinking a little before bedtime can keep you going throughout the night, (On the other hand, if you drink too much, it could keep you going throughout the night!)

Advice on drinking water before and after meals varies greatly:

• between 30 mins and 90 mins before meals,
• at least one source says ‘2 glasses around main meal’,
• others say between 30 and 150 mins after meals,
• some reckon that drinking during meals or within 30 minutes ‘interferes’ with digestion.

Some claim specific reasons for particular times e.g.

• 30 minutes before meal: help digestion
• after waking up: helps activate internal organs
• before sleep: to avoid stroke or heart attack
• before taking a bath: helps lower blood pressure.

Exercise:
20 -30 mins before exercise, within 20 -30 mins after exercise.

I can still hear some sceptical Monty Python fans saying:
“Yes, but apart from keeping us alive, allowing chemical processes, aiding digestion, lubrication and cell growth, preventing kidney failure, headaches and hangovers, eliminating waste and preventing us from frying, just what does water do for us?”