Your body needs water to work properly, but it’s not always easy to know if you are drinking enough, especially in the summer months. Excessive sweating on hot days or when exercising vigorously can cause significant fluid loss. So while you may be drinking, it may not be enough.
Thirst is a sign your body is already dehydrated. So having water beside you during the day and drinking moderate amounts regularly is a good way to keep the balance right.
The human body is 50 to 75 per cent water. Dehydration occurs when your water intake is not enough to replace the water lost through normal bodily functions. Most adults lose about 2.5 litres a day.
You replace water by drinking, eating (20 per cent of your total water requirement comes from food) and digestion. Water is a by-product of digestion, providing 10 per cent of your daily requirement.
Staying hydrated is important to keep your cells and organs in good condition. Even mild dehydration can affect your ability to think clearly. Not drinking enough can cause constipation and, when severe, obstruction of the bowel. Dehydration can also increase your risk of kidney stones and, in women, can increase the risk of urinary tract infections.
Some people need extra care in hot weather. Babies and young children are not able to get themselves the fluid they need or may stop drinking when they are sick.
Dehydration can be life threatening in babies and children and requires urgent medical attention. Symptoms to look out for are cold skin, lethargy, dry mouth, a blue tinge to the skin, and a depressed fontanelle (the soft spot on the top of a baby’s skull).
It's important to encourage your child to drink while at school. They may become distracted when playing and forget to drink.
People with a chronic illness or who take certain medications can also be at higher risk of dehydration. Others may be advised by their doctor to restrict their fluids for medical reasons.
Age, too, is a factor. When people reach their 50s, their thirst sensation reduces and continues to reduce over time. Some elderly people may not know when they need to drink. They may also have impaired kidney function and other illnesses that make them at increased risk during a heat wave.
Knowing when you are dehydrated can be confusing. While darker urine (the colour of apple juice, for example) can be a sign of dehydration, some medications, vitamin supplements and foods can cause such colouration.
It’s also possible to confuse thirst with hunger, so you reach for a snack instead of a drink.
How much should I drink each day?
There’s no easy answer. Men have a higher content of water in their body than women and require more water each day. The Victorian Government’s Better Health Channel recommends women drink at least 8 cups (2 litres) of fluids a day and men drink 10 cups (2.5 litres) to prevent dehydration.
Click here to see recommended daily fluid intake guidelines for all age groups.
These recommended amounts are only a guide because some people need more fluids, for example:
people on a high-fibre diet (to prevent constipation)
pregnant and breastfeeding women
people who are vomiting or have diarrhoea
people who are physically active
people in warm and hot conditions
If you're not sure whether you need to increase your fluid intake, It’s best to consider multiple factors:
Have I drunk enough according to the guidelines for my age and sex?
do I feel thirsty?
is my urine a darker colour than usual?
does my urine have a stronger smell than usual?
do I have a health condition or take medication that requires me to drink more?
how hot is it?
how much strenuous activity have I been doing?
have I been vomiting or having diarrhoea?
what other symptoms of dehydration do I have?
Does it matter what I drink?
The reason most health professionals recommend water is because it does not contain sugar (that may cause tooth decay and unwanted weight gain) and salt (that may cause high blood pressure and fluid retention). Consuming overly sugary or salty food and drinks can cause changes inside your cells that may lead to dehydration. Certain drinks, such as coffee, other caffeinated drinks and alcohol, are diuretics and can cause you to lose more fluid than you’ve drunk, leading to dehydration. For example, for every 200 ml of beer you drink, you urinate about 320 ml.
What if I can’t drink enough?
If you are severely dehydrated and can’t drink enough, you may be given intravenous (IV) fluids to replenish your water store.
Can I drink too much water?
Excessive rapid drinking can cause a rare condition called hypnonatraemia, or water intoxication. It happens when a high amount of water in the body causes serious dilution of the blood’s salt level.
Do I need sports or energy drinks?
When large amounts of water are lost through excessive sweating or sickness (fever, vomiting, diarrhoea), electrolytes such as sodium and potassium are lost. For example, your doctor may recommend electrolyte replacement if you have severe vomiting or diarrhoea.
Water is a great fluid replacement for most moderate levels of physical exertion. Many factors determine an athlete’s requirement for electrolyte replacement. Speak to your doctor about whether you need a special drink for your level of activity.
Symptoms: what to look out for
Symptoms of mild dehydration may include:
darker or strong-smelling urine
parched lips and tongue
confusion or not thinking clearly
low volumes of urine
increase in pulse and breathing rates
Smart choices to stay hydrated
Kelly Conte, BSc. MNutrDiet
Accredited Practising Dietitian, Campaspe Family Practice
Drink lots of refreshing, unsweetened water
Water is the best drink! Bottled water or from the tap are both good choices. You can add slices of citrus fruits, strawberry or mint to add flavour and interest. Take a bottle of water with you when you go out. Try to have a drink of water before meals.
Limit soft drinks, fruit drinks, cordial and other sugar-sweetened drinks
Limit soft drinks, sweetened teas, fruit drinks, sports drinks, ‘energy’ drinks, or your favourite coffee to special occasions. Coffee is a diuretic and will flush out water from your system. Sports drinks are very high in sugar and 'energy drinks' are not only high in sugar but also in caffeine, which is a diuretic.
Drink alcohol in moderation
Alcohol is also a diuretic and can dehydrate the body. If you choose to drink, have a glass of water between alcoholic drinks and don't drink more than two standard drinks on any day.
Nourishing and hydrating foods:
Many fruits have an excellent water content, including watermelon, rockmelon, oranges, pears and apples. They can help keep you well hydrated in the warmer months. They also have many nutritional benefits such as fibre for helping you keep regular and vitamins and minerals which can be found in commercial sports drinks.