Should You Be Drinking a Glass of Water Before Bed? Here's What Dietitians Have to Say

Find out if it ~really~ matters when you hydrate, or if the health benefits of drinking water before bed are a pipe dream.

woman drinking water before bed
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While it's easy to overlook, next to the muscle, bone, organs and fat in our bodies that often step into the spotlight, water actually makes up 55% of the average adult female body and about 60% of adult male bodies, according to Cleveland Clinic.

Just like the grass in a park and the plants in an herb garden require water from rain, a hose, sprinkler or watering can to grow and thrive, "We depend on water to survive," says Katherine Brooking, RD, co-founder of the nutrition news company Appetite for Health in San Francisco. "Water helps to restore fluids lost through metabolism, breathing, sweating and the removal of waste. It also helps to keep you from overheating, lubricates the joints and tissues, maintains healthy skin and is necessary for proper digestion." (ICYMI, here are 7 science-backed health benefits of water.)

It's essential we consume water each and every day, yet most people don't meet their daily water goals, confirms Roxana Ehsani, RD, CSSD, a registered dietitian nutritionist in Miami and a national media spokesperson for the Academy of Nutrition and Dietetics. In fact, according to some scientific estimates, about 75% of Americans are chronically dehydrated—and this isn't doing our health any favors. A study in the ACSM's Health & Fitness Journal found that even subtle dehydration of around 2% can trigger fatigue, headaches, difficulty concentrating, lightheadedness and more.

"Maintaining proper hydration can have a profound impact on how we feel," says Lauren Manaker M.S., RD, LD, a registered dietitian and owner of Nutrition Now Counseling in Charleston, South Carolina. "For those focused on how their skin appears, being properly hydrated can have a noticeable positive impact on the appearance of your skin, too."

To try to increase the brain, body and skin benefits of water, after realizing they've been walking around parched all day, some people swear by pounding water before bed. It sounds like a decent strategy to help cover your H2O needs, but could this strategy backfire? We asked the experts to spill.

The Benefits of Drinking Water Before Bed

As we mentioned, 3 in 4 Americans might not be drinking enough fluid throughout the day or consuming enough water-rich foods to fill in the gaps.

"Making a habit of drinking water before bed can help people meet their fluid quota during the final minutes of their day. For some people, drinking water before bed may help them sleep better by allowing them to produce sweat, keeping them cooler and more comfortable," Manaker says, or by helping moderate body temperature, Brooking adds.

Since temperature plays a big role in your ability to sleep soundly, this can certainly be a boon.

The Drawbacks of Drinking Water Before Bed

Still, gulping down several glasses of water just before you tuck in isn't the wisest strategy, Brooking, Ehsani and Manaker agree. That's because "drinking water right before bed, especially if the quantity is too large, can cause you to wake up frequently needing to pee, which can negatively impact sleep," Manaker says.

While some people believe that drinking water right before bed may help them lose weight, Brooking says that the jury is still out about that; it's actually highly unlikely to really move the needle. Plus, the possible disruption of sleep that may result (from going to the bathroom several times throughout the night) may offset any benefit.

"Poor sleep can impact hunger and satiety hormones; making you hungrier during the day," Brooking says. (BTW, here's more about what happens to your body if you don't get enough sleep.)

Drinking water right before bed doesn't necessarily assist with weight loss, Ehsani adds. True, there are studies linking sufficient water intake with weight loss overall, but that's not related to intake before bedtime. It's related to drinking sufficient water at and around mealtimes, she says.

The amount of water you should drink before bed depends on a few factors, including:

  • How much water you drank earlier in the day
  • If you exercised
  • The temperature of your surroundings (higher heat leads to more sweating, and more H2O is required to help support that)
  • Your body size

For the average person, "I'd say 8 to 12 ounces of water before bed should be enough to quench your thirst—and hopefully not too much to make you run to the restroom a few times throughout the night," Ehsani says. "Everybody is different, so you can test out amounts and see what works best for you to stay hydrated and benefit from a good night's sleep at the same time."

The Bottom Line

Timing is less important than overall fluid intake during the course of the day, Brooking says, and spacing out your water intake will not only aid in any weight-maintenance goals but will also keep energy levels higher, your brain sharper and your bladder balanced out so you don't have to wake up time and time again to run to the bathroom in the middle of the night.

"I recommend staying hydrated throughout the day, then tapering fluid intake an hour or two before bed to minimize sleep disruption," Brooking says. "Remember that for weight loss there's (still!) no magic bullet. Tricks like super-hydrating right before bed won't yield great results and may backfire by interrupting your sleep."

The body regulates its fluid balance over the course of the day, so supplying it with what it needs all day long can offer some benefits, Manaker says. It's ideal to drink water at steady-ish intervals rather than drinking one large amount at a specific moment in time.

The National Academy of Medicine recommends 11½ cups of water per day for women, and 15½ cups a day for men. (Yes, hydrating foods, tea and coffee count!)

"Nowhere near that number? Start slowly and work your way up," Ehsani says. "Only drinking 4 to 5 cups now? Make a goal of at least 6 glasses per day."

To move the needle, try these additional hydration-supporting tips:

"To prevent having to drink tons of water at night and then interfering with your sleep, aim to drink consistently throughout the day to stay hydrated," Ehsani concludes.

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