Almost all of the major systems of your body depend on water to work properly. Drinking plenty of water helps your body:
- regulate temperature
- prevent constipation
- flush out waste products
- perform many other important functions
Most people, especially those who exercise in hot weather, are more concerned about not drinking enough water. However, drinking too much water can also be dangerous.
Overhydration can lead to water intoxication. This occurs when the amount of salt and other electrolytes in your body becomes too diluted. Hyponatremia is a condition in which sodium (salt) levels dip to dangerously low levels.
If your electrolytes drop too low too quickly, it can be fatal. Death by overhydration is rare, but it can happen.
There are two types of overhydration:
Increased water intake
This occurs when you drink more water than your kidneys can remove in your urine. This can cause too much water to collect in your body.
This occurs when your body can’t get rid of excess water. Several medical conditions can cause your body to retain water. This can be dangerous because it throws off the balance between water and sodium in your blood.
Overhydration is an imbalance of fluids. It happens when your body takes in or holds on to more fluid than your kidneys can remove.
Drinking too much water or not having a way to remove it can cause water levels to build up. Endurance athletes, such as those who run marathons and triathlons, sometimes drink too much water before an event.
Some conditions and medicines cause overhydration by making your body hold on to more fluid. These include:
- congestive heart failure (CHF)
- liver disease
- kidney problems
- syndrome of inappropriate antidiuretic hormone
- nonsteroidal anti-inflammatory drugs
Other conditions and drugs increase water intake by making you extremely thirsty. These include:
- uncontrolled diabetes
- MDMA (commonly known as ecstasy)
- antipsychotic drugs
Overhydration is more common among endurance athletes who drink large amounts of water before exercise. It has been reported among these groups of athletes:
- people who run marathons and ultramarathons (longer than 26.2 miles)
- ironman triathletes
- endurance cyclists
- rugby players
- elite rowers
- military members involved in training exercises
This condition is more likely in people with kidney or liver disease. It can also affect people with heart failure.
You may not recognize symptoms of overhydration in its early stages. As the condition progresses, common symptoms include:
Untreated overhydration can lead to dangerously low levels of sodium in your blood. This can cause more severe symptoms, such as:
Your doctor will ask about your medical history to find out if your symptoms are caused by overhydration or another condition. The doctor will also perform a physical examination, and may order blood and urine tests.
How you’re treated for overhydration depends on how severe your symptoms are and what caused the condition. Treatments may include:
- cutting back on your fluid and salt intake
- taking diuretics to increase the amount of urine you produce
- taking medicines to reduce symptoms such as nausea, seizures, and headache
- treating the condition that caused the overhydration
Endurance athletes can reduce the risk of overhydration by weighing themselves before and after a race. This helps determine how much water they have lost and need to replenish.
Try not to drink more than 1 liter of fluid per hour. Instead of drinking a lot of water, have a sports beverage. These drinks also contain electrolytes such as sodium and potassium, which you lose in sweat.
If you have a medical condition such as diabetes, CHF, or kidney disease, talk to your doctor about the best treatments. Also contact your doctor if you’re unusually thirsty. This could be a sign of a medical problem that needs to be treated.