Summer 2011/12 True Natural Health Magazine – Your Questions Answered
By Roger French
QUESTION: The standard recommendation is to drink two litres of water a day, but I strongly dispute this. Why should someone living in a cold climate need the same amount of water as someone in a hot climate? Why should a small or slim person have the same water intake as a large or obese person? And why should a person eating a lot of fruits and vegetables drink the same quantity of water as someone eating a lot of concentrated foods? The standard advice seems quite illogical to me.
During colder weather, I can go a whole day without raising a thirst. I would have to force myself to drink even half the recommendation.
Can you please enlighten me re these questions?
ANSWER:
Your points are spot on! It has always seemed ridiculous to have a flat recommendation for drinking water, regardless of climate, temperature, body size, diet and other factors.
Like you, on a cold day, I hardly think of drinking, whereas on a hot summer day when working hard physically, I want litres of water. Further, a big person must need much more than a small person.
You are right about diet. People eating a lot of junk foods and drinks need more water to flush toxins out of their systems. You and I eating natural foods take in a lot of pure water in our veggies and fruits. In fact, eating one-and-a-quarter kilos of fruits and veges in a typical day provides me with just over one litre of pure water. I sure don’t need to drink two more litres. Fact is, I couldn’t fit it in.
An excellent answer to the question of how much water is given by the Osteopath, Chiropractor and Naturopath, Dr Greg Fitzgerald. His abridged explanation is as follows.
Greg reflects that the entire human organism acts intelligently. Sensations such as hunger, thirst, tiredness, sleepiness, etc., all have survival value, are intelligently directed, and have been guiding humans for millions of years. Only recently were we told by supposed experts that these signs are wrong. Fortunately, a more enlightened approach is taking hold.
Drs Tim Noakes and David Martin, from South Africa and the USA respectively, have stated: “It has been difficult to find any studies in which dehydration has been identified as the causative factor in even a single case of exercise-related heatstroke.” Indeed, drinking too much water, or water gorging, has been shown to cause hyponatraemia, or low blood sodium, with serious consequences.
Their studies led to USA Track and Field, the governing body of track and field in the US, making major revisions to drinking guidelines for athletes. Instead of drinking as much as they can, the guidelines now say they should drink when they are thirsty. Following this, the International Marathon Medical Directors Association has also reversed its stance. Drink when thirsty!
Greg draws attention to a document, written by the Glycaemic Index Association Dietitian, Nicole Senior.
Nicole says that it is a myth that everyone should drink 8 glasses of water a day. Most adults need around 2 – 2½ litres of fluid daily, but needs vary greatly according to climatic conditions, physical activity, body size, diet and health status. Eight glasses of water is eight metric cups (or eight 8-ounce glasses) or 2 litres. Some experts say there is absolutely no scientific foundation for this advice.
Nicole continues that it is well known that we can’t survive long without water. Survival time could be as long as a week or as little as a few hours for a marathon runner experiencing catastrophic heatstroke. About half the water needed each day goes to sweat and water vapour in our breath. Replacement of lost water is vital to maintain normal functioning.
The 8-glass rule fails to recognise that we don’t have to drink all our fluid requirements. There is a lot of water in food, especially fruits and vegetables as well as liquids and semi-solid foods like soups and yoghurt . According to Australia’s last national nutrition survey, the intrinsic water in food contributes 700 – 800 ml per day. In addition, around 250 ml (1 metric cup) per day is produced by our metabolism. So more accurately, the rule should be more like 4 – 6 glasses a day.
What about thirst? We have been told that the thirst mechanism is a poor indicator of our fluid needs and we should drink even though we aren’t thirsty. But perusal of the scientific literature suggests this is only true in elite athletes because their fluid needs are higher. For the rest of us, our thirst serves us well.
So, concludes Nicole, drink when you feel thirsty and don’t feel you have to gulp down 8 glasses of water a day.
Finally, if there is genuine dehydration, what are the signs. Jeff Novick of the USA lists them as:
Early signs: headache, fatigue, loss of appetite, flushed skin, heat intolerance, light-headedness, dry mouth and eyes, burning sensation in the stomach and dark urine with a strong odour.
More advanced dehydration: difficulty swallowing, clumsiness, shrivelled skin, sunken eyes, dim vision, painful urination, numb skin, muscle spasms, delirium and (possibly) muscle cramps.
We certainly want to make sure we don’t ignore genuine thirst and get into this state.
