Water Intoxication – Why Drinking Too Much Water Is Harmful
Water Intoxication - Why an Increased Fluid Intake Is Harmful
Water intoxication results from an excessive fluid intake. If you drink several litres of water within a few hours, your blood becomes so diluted that the salt concentration drops to a worrying level. This leads to health problems that are life-threatening. Here's what you need to know about water intoxication!
The Recommended Amount to Drink
As the human body is made up of 70 per cent water, drinking regularly is important. Experts consider two litres of water a day appropriate for maintaining vital bodily functions. It's recommended that you spread this amount out over 16 hours. Water intoxication occurs when you take in more than five litres of fluid within three hours. Around 250 cases of endurance athletes dying from excessive drinking have been documented worldwide. The drinking contest held by a Californian radio station became sadly infamous after a 28-year-old participant died of water intoxication that same day.
What Puts Your Water Balance at Risk
If you take in an excessive amount of water in a short space of time, your body is literally flooded with fluid. This leads to water intoxication, which severely disrupts the body's electrolyte balance. Together with water and minerals, salts are an essential component of every cell and the spaces between them. Sodium and potassium in particular play a key role in the health and function of the body's cells. When too much water suddenly flows into the tissue, an imbalance in salt concentration develops inside and outside the cells, resulting in water intoxication. Doctors know this condition by the medical term hyperhydration.
How the Body Reacts
When the salt concentration drops during water intoxication, the body switches to energy-saving mode to compensate for the deficit. This emergency response mainly affects the heart, brain, lungs and kidneys. The result is an irregular heartbeat. The kidneys also stop producing urine so that the remaining salt levels can be maintained. As water intoxication spreads, the brain tissue becomes flooded. This situation is extremely critical, because the swollen brain cannot expand within the bony skull. Initial symptoms of water intoxication include dizziness, vomiting, headaches and cramps. The increased pressure on the brain fills the air sacs in the lungs with water, causing pulmonary oedema with breathing difficulties. As a result, those affected can fall into a coma and lose their life.
What Endurance Athletes Should Keep in Mind
Inexperienced marathon runners and triathletes are often unaware of the risk of water intoxication. That's why sports physicians at TU Munich examined the drinking habits of 10,000 endurance athletes. The scientists found that a third of the subjects showed significant disruptions to their water balance. 50 test subjects showed life-threatening levels. Their participation in the competition ended in intensive care. To avoid water intoxication, it's important for beginner athletes to know how much water the body actually needs during training and competition. Experts estimate that, depending on outside temperature, sweat rate and exertion time, marathon runners can lose up to 1.5 litres of water and 3.0 grams of salt per hour. This is why so-called drinking training was developed to help prevent water intoxication.
If an endurance athlete loses one kilogram of weight under competition conditions, the water loss amounts to one litre. However, sports physicians advise against replacing this deficit on a 1:1 basis. Precisely because the danger of fatal water intoxication is well known, experts recommend that athletes keep their fluid intake below this level rather than matching it exactly. The optimal approach is to give the body just half a litre of water. If you drink to excess or drink in advance to build up a reserve, there's an acute risk of intoxication. To replace lost salts and minerals, extreme athletes turn to hypertonic drinks and gel-like concentrates from specialist retailers. Under Swiss food law, these products must contain 300 mmol/kilogram. If you're asking less of your body in terms of performance, the electrolyte loss can be made up with a few salt pretzels.
What Risk Infants Face
Babies are particularly at risk of developing water intoxication during the first six months of life. This is because their kidneys are not yet fully developed. Their excretory organs are not yet able to cope with larger amounts of water. If your child is affected by a disturbance in their water and electrolyte balance, they will appear puffy and lethargic. If the symptoms go unrecognised or untreated, water intoxication results in unconsciousness and seizures. Paediatricians therefore advise against giving babies plain water during the first six months of life, even in summer temperatures. In their view, meals such as breastfeeding and bottle-feeding are enough to cover a baby's fluid needs. If the infant is encouraged to drink on top of this, there's a risk of overhydration.
Between the sixth and twelfth month, babies are less at risk of water intoxication. By this age, kidney function is already fully developed, so fluid balance can be regulated more effectively. In addition, babies are already eating solid and salted food by this stage. If you're unsure, ask your paediatrician whether unsweetened tea can also be offered. It can help to keep a written record of how much fluid your baby takes in.
How to Keep Your Water Balance in Equilibrium
Because men sweat more, they naturally have a higher fluid requirement than women. The right amount to drink also depends on your personal eating habits. If you mainly eat fruit and vegetables, your body needs less water. If you eat mostly salty, fatty food, you definitely need to drink more. Be careful with diets! Because weight loss diets involve drinking more than eating, the risk of water intoxication increases as a result. Fever, exercise and summer heat are all reasons for an increased fluid requirement. In cases of vomiting and diarrhoea, water and electrolyte loss may need to be corrected by a doctor. Patients with stones in the ureter or kidneys should drink at least 1.5 litres a day. Since the body can't store water, drinking in advance to build up a reserve is strongly discouraged. This is the only way to minimise the risk of water intoxication!
