I hear it all the time: I don’t drink enough water…
The details on how much we supposedly ‘need’ to drink varies – but the core ‘wisdom’ is the same. Drink water. Lots of it. Nothing else counts, either, apparently. Every healthy living magazine, newspaper and website seems to reinforce this ‘drink water’ message and so it may come as a big surprise to learn that this is one of the biggest health myths around.
Water is certainly important. However, there is no evidence supporting any specific quantity of water healthy, regularly active people need to drink…
Where Did This Idea Come From?
The earliest ‘popular’ reference to this recommendation for water was in a newspaper obituary. A leading US nutritionist by the name of Frederick Stare died in 2002 and his obituary said that he was famous for suggesting people drink six glasses of water a day. In his book, written in 1974, he did suggest drinking 6-8 glasses of water but that water is very well regulated in the body and that fruits and vegetables were good prime sources, as were coffee, tea, etc. He wrote those two sentences about water at the very end of his long text – almost an afterthought. He was clear that healthy food sources were the key and were adequate but somehow this statement got spun into the media hype we continue to see that exhorts us all to drink 8 glasses/day. It has spawned everything from a list of experts, including physicians, repeating this…..and saying you must drink X oz….all competing with those who say Y oz and several iterations of ‘organic water’, ‘vitamin supplemented water’ and the like. There was no evidence to support his statement back then – and there is still no sound support for the idea now.
Why Drinking Water in Large Quantities is Not Needed
Our bodies are very efficient.
Water provides key chemicals that allow for metabolic reactions to occur, for food to be dissolved, and for transport throughout our bodies. Water is certainly the most vital requirement for human life. Indeed, many of these metabolic reactions also CREATE water – precisely because it is so important.
If someone is healthy, they really only need to concern themselves with increasing their water intake after they have exercised or during the times when they are in hot climates. Eating a good diet goes a long way, and the other beverages we drink are more than sufficient to meet our water needs.
The Dehydration Myth
Especially for those who are active, it is important to know the symptoms of dehydration. For mild to moderate dehydration, the symptoms are dry mouth, eyes and lips, headache, tiredness and a decreased urine output.
Severe dehydration symptoms include extreme thirst, very dry mucous membranes (eyes, lips, mouth, genitals), passing a very small amount of dark urine, and a lack of sweating.
In healthy adults thirst is triggered by an increase in the ‘concentration’ of our blood products – caused by a reduction in fluid – this thirst response happens when our blood concentrations have increased by two percent/our fluid levels have dropped by two percent. Dehydration sets in when that concentration of proteins has increased by five percent/our fluid levels have dropped by 5 percent.
So You’ll Be Thirsty Long Before You Are Dehydrated – Most People Can Drink When They Are Thirsty And Will Be Just Fine.
It is also a myth that coffee, tea etc dehydrates you. You get a tiny bit less water out of that 6 oz mug than if it were pure water – but the net balance is still that you get more water than you had before. Despite what you hear, coffee and teas won’t magically suck water out of your body (dehydrate you).
Can You Drink Too Much Water?
Yes. Drinking excessive amounts of water can cause hyponatremia, an abnormally low level of sodium in the body. Lots of water at once can also cause the kidneys to falter and cause a drop in blood sodium. The problem is that a drop in sodium can cause the brain to swell. Altered electrolytes can be harmful for muscle particularly sensitive heart muscle. Very healthy people die of hyponatremia by drinking too much water.
Bottom line? If you are an average person in the UK with no health issues requiring specific amounts of water, drinking to thirst is the water intake guideline supported by the evidence.
Written by Tracy Hannigan – Tracy Hannigan Osteopath