If you don’t spend all day sipping water from a two-liter Stanley cup, are you really alive? Hydration is once again in the spotlight — TikTok videos with a hashtag on the topic have more than 1 billion views.
Whether drinking from a modern tumbler or a simple regular glass, there is no single answer to how much water you should drink each day. The closest water consumption recommendation the United States has comes from the National Academy of Medicine, which in 2004 reported that healthy men generally stay adequately hydrated when they drink at least 3 liters (almost 13 glasses) of water per day. and that women are generally hydrated when they drink at least 2.2 liters (just over nine glasses) per day, not including water consumed through food.
But these guidelines should not be considered an absolute rule, experts say.
“Most people, even if they fall below this recommendation, will be fine,” says Siddharth P. Shah, a nephrologist at the Hospital of the University of Pennsylvania who specializes in hydration and electrolyte balance.
When should I drink water and how much should I drink?
Water is, of course, crucial to our survival. It helps us eliminate waste, maintain blood pressure, regulate body temperature and much more.
Some people need more water than others. People who are especially active — who have physically demanding jobs or who exercise a lot — lose more water through sweat and will need to compensate by drinking additional water, says George Chiampas, an emergency medicine specialist at Northwestern Medicine and medical director of the Football Federation. U.S.
People may also need to drink more if they live in hot climates, have larger bodies or a lot of muscle mass, have loose stools, are pregnant or breastfeeding, or have had kidney stones or recurrent urinary tract infections, experts say.
Over the course of a lifetime, a person’s water needs also change. Typically, as people age, they lose muscle and gain fat, says Shah. Because fat contains less water than muscle, people generally need to consume less water as they age to maintain healthy tissue.
However, some seniors still don’t consume enough water, Shah says, because older people’s bodies — especially, research suggests, those over 60 — aren’t as good at detecting thirst. The level of dehydration “that would make you thirsty at age 40 may not make you as thirsty at age 80,” he explains.
If you feel thirsty, you’re probably dehydrated and should drink water, says Alysia Robichau, a family and sports medicine physician at Houston Methodist.
There may also be more subtle signs of dehydration, like constantly feeling cold or having dry skin, says Robichau. People who are acutely or chronically dehydrated may also experience headaches or dry eyes, she adds.
Because we don’t drink water while we sleep, “most people wake up and are already dehydrated,” says Chiampas. It’s generally a good idea, he points out, to start the day with a glass of water.
It’s perfectly fine to add flavors to your water or drink sparkling water, says Robichau—but she warns that coffee and other caffeinated drinks may not be as hydrating as caffeine-free drinks. Drinking a caffeinated beverage, especially if you don’t drink them regularly, can reduce your kidneys’ ability to absorb water, causing you to lose additional water through urine. Alcoholic drinks also dehydrate.
Remember that you can also get water from food. Some fruits and vegetables, like watermelon and celery, are mostly made up of water, says Shah. The National Academy of Medicine has estimated that people get, on average, 20% of their water from food.
Most people probably won’t drink too much water, but it is possible, especially among endurance athletes who drink a lot of water quickly, says Chiampas. Doing so can upset the body’s sodium and potassium balance and lead to potentially fatal water intoxication.
The CDC (US Centers for Disease Control and Prevention) advises not to drink more than 1.5 liters of water per hour. Also keep in mind that there is probably no health benefit to drinking tons of water.
“There are a lot of overly large water bottles being carried around these days,” says Shah. “But the vast majority of people don’t need to drink excess water.”