FoodHealthHow much water should we be drinking?

Drinking sufficient water can support immunity, help with circulation, regulate body temperature and serve as an appetite suppressent — all worthy goals at the start of a new year.

In rare cases, however, you can drink too much, causing nausea and headaches, and in extreme circumstances, vomiting and diarrhea. 

So what’s the magic number? How much water should we actually be drinking? It’s not an easy answer, and body weight, activity level and environmental factors must all be taken into consideration. 

The commonly accepted volume is two liters of water, which equates to eight glasses per day. But taking into account exercise, the dry climate and time spent in air conditioning, should it be more? Or less?

The science says your kidneys can process between 20 to 28 liters of water per day. You’re probably not going to drink that much, however, and if you do it should be spaced out over the day, as your kidneys, which work as a filtration system, can only process about 0.8 to a liter of water every hour. 

Drinking too much water could induce a condition called hyponatremia, which is when there is too little sodium in your blood. Hyponatremia can result in nausea and vomiting, headaches, short-term memory loss, confusion, lethargy, fatigue, loss of appetite, irritability, muscle weakness, spasms or cramps, seizures and even decreased consciousness or coma. 

Sinead Scott, nutritionist at Native Club at Zabeel House by Jumeirah in Dubai, The Greens, says if electrolyte levels drop too low, it can be fatal. 

“People can also develop over-hydration if they have a disorder that decreases the body’s ability to excrete water or increases the body’s tendency to retain water,” she explains.

Basically, drinking too much water can produce symptoms similar to not drinking enough water. But don’t panic – it’s not easily done and it’s far more likely you’re not getting enough of the clear stuff. 

Sinead says there’s a relatively easy calculation you can do: “The amount of water you should drink should be based on your body weight and activity level.”

The formula goes like this: 

Step 1: Determine your weight in kilos. If your bathroom scales only reads in pounds, then divide that number by 2.2 to get your weight in kilos

Step 2: Multiply that number by your age

Step 3: Divide that result by 226.4

The number you get is how many cups of water you should be drinking, taking into account your body mass and age. Don’t be surprised if it’s much higher than you would have thought. For example, a 40-year-old woman who weighs 68 kilograms (or 150 pounds) should be drinking 12 cups daily. 

However Sinead advises that you may need to adjust it upwards based on physical activity. 

“The calculation does not take into account physical activity or excessive sweating,” she explains. “Your water consumption would need to increase accordingly with these factors in play.”

If you experience nausea, vomiting, headaches and overwhelming fatigue, it might be because of too much water. Muscle cramping and spasms can also be symptomatic of drinking too much water. 

And if you’re concerned about hydrating, or feeling like your thirst isn’t quite quenched, you can help with consuming foods that hydrate too.

“Fresh watermelon juice with cinnamon or watermelon slices are a great source of hydration,” says Sinead. “Other sources of hydration are foods that are high in water content such as celery and cucumbers.”

For more healthy hydrating tips, Sinead recommends: 

• starting the day with a glass of lukewarm water, which stimulates digestion
• snacking on hydrating fruits and vegetables throughout the day
• paying attention to signs and symptoms of dehydration
• setting phone reminders to drink water
• drawing consumption targets on water bottles

This article originally ran in January 2020.