How much water to drink?
We all know we need to drink plenty of clean water but how much? And since we all come in different shapes and sizes, how much do I need!
Our body comprises approx 60% water – if it didn’t, we’d be dry as a dead stick but we have blood, mucous, hydrated tissue etc etc so we need to retain this percentage or we certainly will start becoming a dried stick! We flex and bend, have soft tissue – we don’t crack when we move.
We lose water every minute of the day via sweat and urination and naturally this fluid loss varies with weather, coffee consumption possibly (a diuretic – creates a need to urinate, but more later on this) so our fluid replacement intake needs to compensate. Then one wonders whether the size and weight of a person impacts because “the rule” is 8 x glasses water daily (about 2 litres) is what is suggested across the board.
Let’s look at some details to get a better understanding …
By the time we feel thirsty (a loss of fluid equalling 2-3% bodyweight) we are already suffering effects of dehydration. Our mental performance and coordination are impaired when fluid loss reaches approx 1% so we are adversely effected even before we feel thirsty.
Mild dehydration is considered at 1-3% fluid loss and easily comes about with exercise, or heat. Brain function is affected. Headaches can be brought on by a fluid reduction of just 1.36% ! I often wonder if the headache tablet we reach for is what dulls/removes the headache; or is it the glass of water that we drink with the tablets!
As babies, we are approx 78% water and this reduces to about 65% by our first birthday. As adults we comprise 57% – 60% water and this reduces a little as we age. Obese men and women have less water content (as a percentage to their size) than lean adults. Women are comprised of less water than men.
A 1% loss comes about quite easily if one sweats and as we see above, we should help ourselves before this loss is reached … so a 60kg person should be looking to replace 600ml water.
I read somewhere that we can sweat a lot at night and might lose up to 1.5 litres in a night. No wonder we are encouraged to drink half a litre to a litre on rising.
Experts suggest we should be sipping water regularly as opposed to a massive intake just a couple times a day. This seems sensible and it might be easier for most of us to do. The habit that many of us now have of carrying about a water bottle may in fact be a very good one! Plus it’s good if we have a system whereby we know how much water we are drinking each day.
A naturopath told me once that if one hydrates correctly during the day, one can finish up at about 5pm’sh so one’s sleep is not disturbed by bathroom visits.
Water consumption has been seen to increase metabolism for approx 90 minutes.
Cold water uses more calories as the body has to heat the water to body temperature – whilst this makes sense, there are arguments in favour of drinking room temperature water.
Drinking water before a meal has been seen to cause people to eat less, especially older adults. The time between drinking and eating must be long enough for the water to be absorbed so it is not sloshing around in the tummy diluting digestive acids which are needed to beak down food. Leave at least half an hour, even longer.
And for the dieters, a 500ml drink of water (30 minutes or so) before a meal caused a much higher weight loss than the trial group who did not drink the water then. The study was run over a 12 week period and the “water drinkers” lost 44% more weight than the non-drinking group. The researchers put this down to the water-drinking participants eating less.
(Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults. Dennis EA, Dengo AL, Comber DL, Flack KD, Savla J, Davy KP, Davy BM.)
So how much should I drink?
2 litres a day is a good ballpark figure but ADD more if it’s very hot and you’re sweating; or exerting yourself; or ingesting a diuretic (some medications). Don’t wait to feel thirsty and drink smaller quantities throughout the day as opposed to 2 x 1 litre drinks! In cold weather, one may need less as one isn’t perspiring but don’t make it too much less!
Doctors may suggest an amount but often say that our liquid waste should be pale yellow, not deep yellow or dark (insufficient water intake) but not continually totally clear either (too much water intake).
From my own experience, I can handle outside heat and work infinitely better when constantly sipping water (as well as hat and sunnies). Remove the water and I wilt quickly!
And as per below, depending on our food type intake, we may be significantly adding fluid for our body.
Does water help prevent any health problems?
Most definitely …
Constipation is very common but it might surprise you to learn that some folk do not drink any water ever !
This info might create an incentive to drink enough: as our body produces its waste (faeces), if it does not have enough water for its needs, it will draw off what water it can via our colon from our waste! Whilst it is not an ideal way of the body getting it’s much-needed water, it does its best with what we make available. Resultantly, instead of passing approx 12” (30cm) of nice soft waste daily, we pop out hard little pellets – or grenades! Or nothing for days as a time! Nice thought, hey?
Kidney stones can appear incredibly quickly if we become dehydrated. This happened to someone I know when he was overseas, and he was drinking water but in hindsight said it mustn’t have been enough. His doctor diagnosed his acute pain as a kidney stone caused from insufficient fluid. Turns out he was right when my friend passed a small stone the following day that disintegrated on being passed. The kidney gathers waste chemicals such as calcium oxalate or uric acid which are continuously excreted unnoticed until we dehydrate. Then, they build up into an increasingly solid mass and move into and wedge in the urinary tract causing excruciating pain. An acidic body can increase the risk. My friend may have had an uric acid stone as they are softer than other stones such as struvite stones caused by urine infection, and the hereditary but rare cystine stones. The common stone is calcium combined with oxalate or phosphate.
Visit www.kidney.org.au for more information.
Can I drink coffee, tea, soft drinks as part of my two litres?
Plain (pure) water is what is pushed at us to contribute to fluid balance but other sources are good too. Even coffee – which is labelled as a diuretic that reduces fluid levels so much we have to add a couple more glasses of water to compensate – may not as bad as we are lead to believe according to this study:
J Am Coll Nutr. 2000 Oct;19(5):591-600. The effect of caffeinated, non-caffeinated, caloric and non-caloric beverages on hydration. Grandjean AC1, Reimers KJ, Bannick KE, Haven MC.
Their conclusion was that “advice to people to disregard caffeinated beverages as part of the daily fluid intake is not substantiated by the results of this study”. The drinks used in the study included carbonated, caffeinated caloric and non-caloric colas and coffee, water and carbonated, non-caffeinated, citrus soft drink. One study alone, however, should perhaps not be grounds for disregarding the benefits of clean, filtered water as the mainstay of healthy fluid levels.
Many foods contain a significant amount of water so meat, fish, eggs, vegetables, salads all help. This is probably the reason why people who never drink water actually seem to get away with it. But there may be an unseen cost so why risk it when water is so freely available to us.
And what about beer?
An interesting article by Dr Karl: http://www.abc.net.au/science/articles/2012/02/28/3441707.htm
The bottom line is that alcohol reduces our anti-diuretic hormone (ADH – aka vasopressin). ADH is there to slow our body from making urine so our body retains precious fluid. When we consume alcohol, ADH production is reduced so we urinate more… in fact, according to Dr Karl, we urinate more than we drink and even drinking water as well as beer is not going to be the total answer because the alcohol intake interferes with the ADH levels.
And as an aside, the article says the average person produces urine at a rate of a ml an hour per kg of body weight … a 60kg person will generate 60ml urine per hour etc etc.
….. all rather interesting, isn’t it?
We are not healthcare or medical professionals and the information contained here is not to be taken as medical advice. It is recommended that you consult you healthcare professional prior to taking any supplements and always read the label, use only as directed, and if symptoms persist, see your healthcare professional