Dietitians constantly remind us that drinking enough water is absolutely vital in order for our bodies to function properly. And it is – unless you drink too much of it. Though most people look out for the signs of dehydration, over-hydration is equally as dangerous. Drinking too much water can result in water intoxication, also known as hyponatremia, causing the inside of cells to flood due to abnormally low sodium levels in your bloodstream. In severe cases, water intoxication can lead to debilitating health problems such as seizures, coma and even death.

You constantly have a water bottle in hand
If you carry around your water bottle all day and immediately refill it when it depletes, you may be drinking too much water. Constantly adding water to your body can result in low sodium levels in your blood, which can cause all of the cells in your body to swell. According to exercise professor Tamara Hew-Butler, this can become particularly dangerous when your brain starts to swell. “Your brain can only swell about 8-10% before it reaches the skull and it pushes your brain stem out,” says Hew-Butler.

You drink water even when you’re not thirsty
The best way to know if your body really needs more water is to be consciously aware of whether or not you actually feel thirsty. “Our bodies are so programmed to fight against dehydration because we’ve always been living in fear of scarcity or not having enough, so we have all of these built-in mechanisms to protect us against that,” Hew-Butler says. “One of these mechanisms that all animals have is thirst. Thirst is every body’s individual monitor that lets them know if they need more. The more water you need, the thirstier you get.”

You continuously drink water until your urine is clear
If you’re drinking a healthy amount of water, the colour of your urine should be straw-coloured to transparent yellow. Though most people believe clear urine is the healthiest sign of hydration, having urine with no pigmentation at all may be a sign that you’re drinking too much water. For most people, eight to 10 glasses of water a day is considered a normal amount. This suggestion varies depending on an individual’s height, weight and exercise patterns.

You urinate frequently, including during the night
You may be drinking too much water if you find you often wake up in the middle of the night to use the toilet. According to the Cleveland Clinic, most people urinate between six and eight times a day. If you find yourself urinating more than ten times a day, you may be drinking more water than your body needs. Other causes include an overactive bladder and caffeine. To prevent night time urination, have your last glass of water a couple of hours before bed to give your kidneys time to filter the water through your body. (Frequent urination could be an indicator of diabetes insipidus, too.)

You feel nauseous and may experience vomiting
The symptoms of over-hydration look a lot like those of dehydration, according to Hew-Butler. When you drink too much water, your kidneys become unable to get rid of the excess liquid, and water starts to collect in the body. This can cause a number of unpleasant symptoms, often including nausea, vomiting and diarrhoea.

You have throbbing headaches throughout the day
Headaches are both a sign of over-hydration and dehydration, similar to nausea, vomiting and diarrhoea. When you drink too much water, the salt concentration in your blood reduces, causing the cells in the organs throughout your body to swell. When your salt concentration is low, your cells grow. When you drink too much water, your brain actually grows in size and presses against the skull. This added pressure can cause a throbbing headache and more serious health problems such as brain impairment and trouble breathing.

You notice swelling or discolouration in your hands, lips and feet
In many cases of hyponatremia, people will experience noticeable swelling or discoloration in their hands, lips and feet. When all of the cells throughout your body swell, your skin will start to visibly swell as well. Those who drink too much water may gain weight suddenly due to swelling and excess water in the bloodstream. If you’re drinking more than 10 glasses of water each day and notice swelling or discoloration in your hands, lips and feet, consider cutting back on your water intake and see if your symptoms subside.

Your muscles feel weak and tend to cramp easily
Having a healthy, fully functioning body is all about balance. When you drink too much water, your electrolyte levels drop and that balance is compromised. Low electrolyte levels can cause a number of unpleasant symptoms, including muscle spasms and cramping. You can prevent muscle problems by replacing a couple of glasses of water a day with coconut water, which is full of electrolytes and 100 percent natural.

You feel tired or fatigued
Your kidneys are responsible for filtering the water you drink through your body and making sure the fluid levels in your bloodstream stay balanced. When you drink too much water, your kidneys have to work even harder, creating a stressful reaction from your hormones that leaves your body stressed and fatigued. If you’re constantly drinking water and find yourself struggling to get out of bed, it may be because you’ve added unneeded stress to your kidneys.

Written by Lianna Roth Hursh, medically reviewed by Dr Michael Spertus. This article first appeared on Reader’s Digest. For more of what you love from the world’s best-loved magazine, here’s our best subscription offer.