There’s no real science behind the age-old advice to drink eight cups of water a day. We all have heard this but the challenge for many is how but how! And ‘eight glasses’, what does that mean? How much should you be drinking?
It seems like a straightforward question, but unfortunately, there’s no clear-cut answer. We actually know very little about the relationship between hydration and long-term health. But, we do know that water is the one nutrient we can’t survive without for more than a few days. Also, we can live significantly longer without calories, carbs, or essential vitamins.
This gap in information may come from the fact that there is no consensus about the definition of “optimal hydration”.
Because there is no one perfect method for assessing fluid status.
There’s also a shortage of reliable data on how much water and total fluids people drink on average. Relatively few studies have methodically assessed this.
The Institute of Medicine updated its recommendations regarding water intake in 2004. They set the adequate intake for adults aged 19 and older at 2.7 litres daily for women (about 11 cups) and 3.7 litres for men (about 16 cups). These guidelines show average intake rather than a requirement based on actual health outcomes. The recommendations don’t refer to just pure water. They encompass total fluid intake from all beverages (including coffee and tea) as well as foods. About 20% of our daily water needs come from fruits, vegetables, meats, and other foods. This means you don’t actually need to drink 11 to 16 cups of liquid daily to stay hydrated.
The European guidelines, published in 2010, are more conservative. They advise an average intake of 2 litres of total fluid in women (about 8 cups) and 2.5 litres (about 11 cups) in men, again from beverages and food combined. The discrepancy between the U.S. and European recommendations gives you an idea of how difficult it is to set population-wide hydration goals.
Both sets of guidelines are intended for people who do moderate amounts of physical activity in temperate climates. Athletes will have much higher needs. This will increase further if exercising outdoors in hot, humid weather.
Heavy exercisers can lose up to 6 litres of water per day through sweat in extreme conditions. They need to drink an equivalent amount to replace their losses.
For most people, urine colour and volume are a good measure to use. Our bodies adapt to variable fluid intakes by altering the amount and concentration of urine our kidneys produce. If your urine is a pale yellow or straw colour it suggests that you’re drinking enough.
If your urine is dark-coloured or you’re only urinating small volumes, you are likely to be dehydrated. These methods aren’t 100 percent reliable though. If you’re dehydrated but drink a large volume of water quickly, your body will produce pale, diluted urine. This would suggest you are hydrated even though you may still need more. Some supplements and medications can also cause you to produce darker urine for several hours after taking them.
Severe dehydration has serious health consequences. Mild dehydration can be damaging. Research shows that losing just 2 percent of your normal, well-hydrated body weight can contribute to fatigue. It can produce difficulty concentrating, confusion, and impaired mood. Dehydration can also cause headaches. Drinking plenty of water may help to relieve these types of headaches in a relatively short period of time.
One study of migraine sufferers found that drinking an extra 1.5 litres of water a day reduced the intensity and duration of headaches. It did not reduce the total number of headaches they experienced. Dehydration is also a major risk factor for kidney stones, which now affect 1 in 11 adults. Drinking plenty of water is key to preventing a recurrence, especially in hot summer months.
Many people are so busy that they feel they barely have time to eat, let alone pause for a water break. You may find you often go hours and hours without quenching your thirst. Staying hydrated has real advantages. It can help you maintain your energy and focus. This will mean you can operate more efficiently. It is important to give your drinking habits the attention they deserve. Here are some simple ways to make topping up with fluid throughout the day a little easier:
Carry a water bottle with you. If you have desk job, always keep one at your desk. If you have a bottle within arms reach, it’s very likely that you’ll use it throughout the day, without any effort required!
When you’re feeling frazzled or hazy, grab a glass of cold water. Studies show that people feel more alert after drinking water. It’s a simple, healthy way to snap out of a midday slump.
Drink a cup of herbal tea every evening. Make this a habit and you’ll instantly add an extra cup of fluid to your tally every single day. This relaxing ritual is a great way to de-stress at the end of the day.
Eat whole foods. By eating water-rich foods like vegetables, fruits, and yoghurt, you’ll up your fluid intake. Processed snack foods like chips, crackers, and baked goods have minimal water content.
If you’re an elderly adult or a caretaker for one, it’s especially important to pay attention to hydration. Ageing impairs the body’s natural thirst mechanisms, which makes it easier to become dehydrated. It may be helpful to fill up a big water bottle (at least 1 litre) at the beginning of the day, with the goal of emptying it by the end of the day. The water bottle is a physical reminder to drink even if you’re not thirsty.
We hope this helps but if you have any questions ask your GP, they will be happy to help you stay hydrated!