Water, water everywhere….. but exactly how much should we be drinking?

60% of the human body is water. Stored inside your cells, organs and tissues, it helps regulate your temperature and keep bodily functions ticking over. Water is lost through breathing, sweating and digestion, which is why it’s important to replenish your supply regularly. Ditching sugary beverages for some good old water is an excellent way to improve your health, after all sugary drinks are linked to excess weight gain, poor glycaemic control and gout, and ensuring adequate fluid intake can help with constipation. But do you really need to be drinking 3L plus of water a day? Does drinking lots of water help “flush fat” from your body, as I’ve read on some Facebook pages? Does more water help you detox? Below I’ll share with you why water is so important and how much you really need to drink.

What do we use water for?

It’s a part of every single cell within our body. Water is used in many processes within our bodies, including the breakdown of the macronutrients carbohydrate, protein and fat. Water plays a role in regulation of temperature. What happens when you get hot? You sweat! Sweat is made mainly of water, as well as some electrolytes. Sweat helps cool the body when it evaporates from the skin. Water also plays a vitally important role in transportation within the body. This includes getting nutrients into our cells as well as removing waste products from cells. Our blood contains water and adequate water is necessary for optimal blood circulation. When you’re dehydrated, there is less water in your blood, making it thicker. Your heart has to pump harder to get the blood around your body to carry oxygen and nutrients to your cell. That’s why you can feel tired when you are dehydrated.

Hydration is essential for every single organ and system within the body, from the brain, to digestive system to the reproductive system. That’s why severe dehydration leads to death. While that’s the serious end of the scale, mild dehydration does affect your wellbeing. Research shows that mild dehydration can affect your concentration, alertness, short term memory and increase feelings of fatigue. It also affects sports performance.

But how much is enough??

The National Health Service (NHS) advises that we should be drinking around 1-2 litres of water. That’s roughly six to eight glasses a day. In hotter climates, the body will usually need more than this. Higher water intake doesn’t have any additional health benefits. It won’t help you ‘flush fat’, it won’t help you detox (your body does a great job of that already) all it will do is give you more frequent trips to the loo and increase your toilet paper bill! Thirst is only a roughly accurate indicator for hydration status and a late sign of dehydration. When you feel thirsty, you are likely already slightly dehydrated.

A simple way to tell if you are hydrated is to look at your wee. It should be a pale yellow colour. If it’s dark yellow, you could do with some more water. Be aware that vitamin supplements can influence the colour of your urine – so if you are taking these, this chart will not be as useful. Tea, coffee, herbal teas do count towards your fluid intake. While caffeine is a mild diuretic (meaning it makes you urinate), you don’t actually lose more water than you consume. Overdoing the caffeine isn’t a good idea though as it can affect your sleep and leave you anxious and irritable. Stick to a couple of cups of coffee a day.

What happens if I don’t drink enough water?

If you don’t drink enough water, your body will become dehydrated. It occurs when your body is losing more water than it’s gaining. The severity of the dehydration is dictated by the amount of water lost and not replaced. For those who are doing lots of high intensity, or long distance exercise, and sweating a lot, you may need to pay more attention to your fluid needs for optimal sports performance and recovery.

Symptoms of dehydration include headaches, tiredness, dry mouth, lips and eyes and small amounts of urine passing infrequently. These are signs of your body trying to conserve water. Drinking water should reverse the effects.

Water can also play a role in weight loss

Water is involved in many metabolic processes in your body and being dehydrated has the potential to slow your metabolism down which can hamper weight loss.

There’s also a theory that having a glass of water before a meal can make you feel satisfied faster, meaning you eat less calories. A 2010 study by the Department of Human Nutrition, Foods and Exercise in Virginia confirmed this connection, showing that water consumption acutely reduces meal energy intake among middle-aged and older adults.

And one more thing – poo. If you don’t have enough water in your body already, (the large intestine soaks up water from your food waste) making poo is hard, literally, your poo becomes hard and difficult to pass. Increasing fluid can relieve constipation. When we exercise we lose a lot of water through sweat. Ensuring you’re hydrated before intense activity can help you perform at your absolute best.

So while water doesn’t help flush fat, or detox your body, it is a vital component of keeping our bodies functioning optimally. In general, 8 glasses of water should be sufficient, but you’ll probably need more on hot days and when you are exercising.

One last thing, the 8 glass rule is based on American size drinking lasses which tend to be bigger than ours so aim for a couple more. Use the colour of your urine as a guide to keep yourself well hydrated and use an app such as My Water Balance if you think you need help to drink more fluids.