Drinking enough water has become something of a status symbol (see the Stanley water bottle going viral). But while the old “drink eight glasses of water a day” line has reigned supreme for many years now, Emily Leeming, PhD–whose book Genius Gut will be released next month–points out that this is an arbitrary number and not based on any real evidence.
“We each have different fluid needs based on the size of our bodies, and our own needs can change day-to-day too,” she explains. “That can include how hot the weather is, how much salty food you’ve eaten, and how much exercise you’ve done.”
During the summer, when temperatures rise, you’ll need to drink more water than on a similar day during winter. In the US, 75% of people are chronically dehydrated, while in the UK, 60% drink less than a single glass of water a day. Whatever your personal metrics, that isn’t enough.
Signs that you are dehydrated include headaches, thirst, and difficulty focusing—even a 2% loss in hydration can make you feel tired and sluggish—but Dr. Leeming says the best way to assess is by looking at the color of your urine.
“When you’re hydrated, your wee will be the color of translucent, pale lemonade,” she explains. “When you need to drink more, it will be dark yellow, so apple juice color or darker. And when you’re drinking too much water, it will be completely clear.” So instead of counting your glasses, commit keeping tabs on your urine and acting accordingly.
“Hydration doesn’t have to come in the form of just water, either; coffee and tea count too,” Dr. Leeming says. “When it’s hot, you can add herbal teas to cold iced water instead of hot, for a cool flavored drink.” Other ways to add interest to your water include adding slices of lemon, cucumber, mint, or basil, or try Artah’s Cellular Hydration, which is packed with electrolytes to supercharge your hydration status.