It cleanses, hydrates and refreshes – there’s nothing quite like a nice cool glass of water. And not only does it feel satisfying, drinking water is vital for our bodies to function.
But exactly how much should we be drinking? Linda Antwi-Ahima, a pharmacist at Care UK’s Peninsula NHS Treatment Centre, looks at the issue of water and hydration.
Linda said: “Water is essential for life. It accounts for about 60 per cent of our body weight and performs crucial roles such as carrying nutrients and waste products between our major organs, helping to regulate body temperature, lubricating our joints and acting as a shock absorber.
“Every system in our body needs water to function. We lose some of this water every day in various ways, through our breath, sweat, urine, and bowel movements. If you live in a hot climate, you lose even more fluid. By drinking water, we replenish the water loss. Without enough water, our body cannot function properly.”
Signs you might not be drinking enough water
If you experience one or more of these symptoms, it may simply be the result of dehydration:
- Dizziness or light-headedness
- Dry mouth, lips and eyes, loss of skin elasticity
- Passing less urine than normal
- Dark urine
The colour of your urine can be a useful indicator. Here’s a colour chart that can help you decide.
So how much water should we drink daily?
Linda added: “The question of how much water we should drink in a day is one that has many different opinions. You may have heard of the ‘8x8’ rule, which promotes drinking at least eight 8-oz glasses of water a day (1.9 litres).
“NHS experts advise that, in climates such as the UK, we should be drinking around 1.2 litres of water. That’s roughly six to eight glasses a day. Even so, the answer to exactly how much water we should drink isn’t a simple number.
“How much we should actually drink varies between individuals more than we might think. No single formula fits everyone and knowing more about our body's need for fluids will help us estimate how much water to drink each day.
“Fluid requirements vary among individuals based on age, sex, activity level, whether you are pregnant or breastfeeding and even where you live. Your personal fluid requirements also vary each day depending on the other things you are doing, eating, and drinking.
Is it also possible to drink too much water?
“It is possible to overhydrate. Dilutional hyponatraemia is also known as water intoxication. It is caused by low sodium levels in the blood and it happens when you have over hydrated in a short period of time.
“A study of runners taking part in a 2002 Boston Marathon, found that around 90 finishers in that event might have had critical hyponatraemia. These abnormally and potentially dangerously low sodium levels in the blood plasma at the end of the race were put down to excessive fluid consumption, as evidenced by weight gain while running.
“Exercise-associated hyponatraemia (EAH) is the most common type but there are other occasions when over drinking can occur. Some people drink water in excessive quantities in an effort to feel full and to speed weight loss. However, this is not a healthy approach to weight reduction and could potentially be harmful.
“In 2008, in an effort to lose excess weight, 40-year-old woman from Huddersfield on a calorie restricted diet drank around four litres of water in less than two hours. She had a headache lost consciousness and died in hospital the next day. Her inquest revealed cause of death was water intoxication.”
Dr Stephen Mears from the School of Sport, Exercise and Health Sciences at the University of Loughborough is quoted as saying: “Too much water leads to a dilution of sodium in the blood, which effectively drowns cells. It makes them swell and leads to all sort of problems, especially concerning the brain.”
Recommendations for healthy hydration
- If you do any activity that makes you sweat, you need to drink extra water to cover the fluid loss. It's important to drink water before, during and after a workout. If exercise is intense and lasts more than an hour, a sports drink can probably help replace minerals in your blood (electrolytes) lost through sweat.
- Hot or humid weather can make you sweat and requires additional fluid intake. Dehydration can also occur at high altitudes.
- Your body loses fluids when you have a fever, vomiting or diarrhoea. Drink more water or follow a doctor or pharmacist’s recommendation to drink an oral rehydration solution.
- Older people and children are more at risk of dehydration since they are not always regulating their water intake properly.
- Drink at regular intervals throughout the day, in order to meet you body’s water requirements.
- Some foods with diuretic effect such as alcohol and asparagus may cause you to excrete more water so you may need to drink more water to replenish. If you eat high sodium foods, your body will often retain more water leaving you thirstier. Drinking more fluids will help dilute your system and get fluids moving regularly again.
- You don't need to rely only on what you drink to meet your fluid needs. What you eat also provides a significant portion. For example, many fruits and vegetables, such as watermelon and spinach, are almost 100 per cent water by weight.In addition, beverages such as milk, juice and herbal teas are composed mostly of water. However beware of flavoured drinks that can contain large amounts of caffeine or other stimulants, sugar, and other additives which are not good for our health.
- Hunger can also be a sign of thirst or dehydration. When you’re dehydrated, it can be difficult for organs like the liver, which uses water, to release glycogen (stored glucose) and other components of your energy stores, so you can actually get cravings for food. If you feel hungry even when you know you have eaten enough, there is a good chance your body is telling you it needs water, not food.