WE’VE all heard that drinking eight glasses of water a day is the target, but is that enough? Could it be too much? And does it have to be water or do other fluids count?
Water is the most vital component of your body and every single cell depends on it. We need water to help eliminate wastes and toxins, carry nutrients and oxygen to cells, help act as a cushion for your nervous system, keep joints lubricated, regulate our body temperature and, most importantly, keep body cells hydrated.
Yet the question still remains. How much water should you drink each day?
Not getting enough
Many of us are walking around in a constant state of dehydration, totally unaware of the health risk it poses. When you’re not getting enough water, you’ll be sluggish, lethargic, and most likely mistake thirst for hunger.
Dehydration (when water loss exceeds intake) can strike in virtually every scenario that involves physical activity. It doesn’t have to be hot and you don’t have to see visible perspiration. You can become dehydrated swimming laps or skiing on a cold day.
Other than making us feel thirsty, common signs of dehydration include dry mouth, flushed skin, headaches, dizziness, constipation, fatigue or muscle cramps. If not treated correctly, severe dehydration can lead to mental delusion or unconsciousness and will require medical attention.
Who needs more?
Circumstances that increase water requirements include dehydrating environments (air-conditioned offices and aeroplane cabins), hot and dry weather, illnesses (vomiting or diarrhoea) and pregnancy and lactation.
High protein diets tend to cause an increased water loss through urine. Likewise, increasing your fibre intake (which most Australians could benefit from) will require more fluids because fibre absorbs water.
You can drink too much water, but it’s rare. The most common effect of too much water in a short period of time is a condition called hyponatremia (a drop in sodium levels in the blood). Symptoms include headaches, blurred vision, cramps, swelling of the brain, coma and in extreme cases, death.
How much should you drink each day?
Common wisdom recommends adults drink 2.1-2.6 litres (8-10 cups) daily, but most experts agree it’s not possible to specify a quantity that is suitable for everyone.
Why? How much water you need depends on how rapidly you are losing it from your body, and this is influenced by many factors including your health status, climate, how active you are, your age and what food and beverages you consume.
In normal environmental conditions, the turnover of water (via breathing, sweating, bowel and urine movements) in most adults is approximately 4 per cent of total body weight. This is equivalent to 2.5 — 3 litres a day in a 70kg adult. The food we consume contributes approximately 20 per cent (about 700-800 ml) of total water intake. So if you drink 2 litres of water each day, along with your normal diet, you typically replace the lost fluid.
Beyond the tap
You don’t need to rely solely on what you drink to satisfy all your fluid needs. What you eat counts, too. For example, many fruits and vegetables, like watermelon and spinach, are 90 per cent or more water by weight. Just another reason to chow down the recommended 5 + 2 serves of veg and fruit every day.
Water, is by far the best thirst quencher, without getting the added sugar and kilojoules found in sweetened drinks, like fruit juices, soft drinks, sports drinks and flavoured mineral waters. Water is also cheap (or free), the fluoride added to it prevents dental problems and it’s good for the waistline.
So how do you know if you are drinking enough water? As far as avoiding dehydration, the proof is in the pee. You will be on the right track if your urine is clear or pale. If it’s darker, keep on drinking!