Who on earth told us that we need to drink eight glasses of water every day in order to stay healthy?
It seems that in 1945 a paper was written that said the body uses 84 ounces of water per day and then again in 1974 a nutritionist said that we should be drinking six to eight glasses of water per day in order that the body can function optimally.
That did not mean as well as the other ways we get water into our bodies but in total! We forget just how much water is in everything we put into our mouths.
Everything from when we are babies and drinking breast milk to adults eating food contains water and our bodies are designed to extract the water from it and process it so that we remain hydrated.
We have a thirst centre in our brains – that acts to tell us when we need to drink more. Otherwise, we really do not need to head for the tap every hour we are awake and we certainly don’t need all those expensive ‘health drinks’ that keep telling us we need in order to add vitamins and other nutrients to our bodies. If the body doesn’t actually need that fluid, we will just pee it straight out again.
The perils of dehydration have been promoted over the years by companies that manufacture sports drinks. Fear that something bad is going to happen to your body if you don’t keep it hydrated by drinking their specially designed products is a powerful influencer. If you are trying to keep fit or even hoping to be an athlete then you want to keep your body in good shape – so you do what is advised – by the ‘experts’ selling those drinks!
Of course dehydration is a real problem and a serious one – but it is caused by specific events, not because you haven’t drunk those magical eight glasses of water every day:-
When it is hotter, you sweat and lose water so you need to drink more.
When you are doing a lot of physical activity you sweat more too so you need to drink more.
If you are overweight you need to drink more.
However, reality is that your kidneys do a great job of keeping our bodies adequately hydrated and in fact drinking too much water probably does more harm to the body than not drinking enough.
How Does It Work?
Interaction between sensors in our brain that detect water imbalance and the pituitary gland in our brain means that when our body needs more water the pituitary gland is immediately informed by the brain and it then secretes a hormone (anti diuretic hormone) that controls the kidney’s pores by closing them so we pee less. Therefore if we are becoming dehydrated, the hormone closes the pores that allow water to be passed out as peeing so that we retain fluid.
If we drink too much then the pores open so that we pee out more fluid so that the balance of the water in the body is maintained. Drinking too much can lead to renal failure.
So What Should We Do?
We should listen to our bodies.
We don’t do that enough these days.
We eat because we WANT to – we see adverts for food and it stimulates our taste buds and so we think we need to eat when really we hadn’t thought about it before we saw the trigger – not because we need to.
Likewise, we often drink when we think we should rather than when the very efficient feedback loop from brain to kidneys tells us that we need to. If we tell ourselves that we really NEED those eight glasses per day then we will fret that we haven’t had them and convince ourselves that we must do so when all we need to do is drink when our brains tell us we are thirsty.
So How Much Should We Drink Every Day?
What we need!
There is no evidence at all to support the idea that we should drink 8 glasses of water every day in order to maintain optimum fitness.
Drink when you are thirsty.
Listen to your body.
It is designed to let us know what we need to do – trust it!