The Benefits of Drinking Water First Thing In the Morning—and 3 Myths About the Practice

Drinking water first thing in the morning is one of those health tips everyone on social media seems to swear by. The advice is simple: Gulp down a glass of water as soon as your feet hit the floor (or maybe even before) and you’ll kickstart your day in the healthiest way possible. 

Staying hydrated is, of course, a good idea at all hours of the day. But does drinking water in the morning before doing anything else really live up to its hype? We asked a registered dietitian and two sleep experts to weigh in on the practice’s benefits and limitations alike.

Benefits of Drinking Water In the Morning

Starting your day with water isn’t just about quenching your thirst—it has other tangible health benefits too. “After a night of losing fluids, rehydrating helps wake up the body and mind,” says Shelby Harris, PsyD, a licensed clinical psychologist board-certified in behavioral sleep medicine and the director of sleep health at Sleepopolis. “It can boost focus, ease that groggy feeling, and give you a fresh start to the day with minimal effort.” 

Here are a few compelling reasons to make drinking water in the morning part of your AM routine:

1. It Kickstarts Hydration

After a solid night of sleep, your body wakes up a little dehydrated because you haven’t had any fluid intake in several hours, says sports dietitian Natalie Rizzo, RD, author of Planted Performance and founder of Greenletes. Since you haven’t been able to replenish any fluids, processes like breathing and sweating overnight can reduce your hydration levels. 

“It’s important to drink water first thing in the morning to start your day hydrated and maintain hydration levels throughout the day,” Rizzo says. Getting enough fluids is also key for your body and brain to function at their best, she adds. “Research shows that dehydration can contribute to fatigue, decreased cognitive abilities, and digestive issues.”

By starting your day with a glass of water, you can begin to replenish your body’s fluid stores, setting you up for a less sluggish morning and day overall.

2. It Boosts Brain Function

Studies show mild dehydration—even as little as a 2 percent fluid loss—can impair concentration, memory, and critical thinking. Rehydrating in the morning can sharpen your focus, help clear away any brain fogginess, and improve mental clarity for better cognitive performance throughout the day.

Of course, improved cognitive performance isn’t only possible after drinking water in the morning specifically—rather, it’s important to get enough fluids all day long. But starting your day with a sharper brain is never a bad idea.

3. It Eases Fatigue

Drinking water in the morning can help you feel more alert, Harris says. 

After all, one of the most common symptoms of dehydration is fatigue, Rizzo points out. “Drinking enough water so that you’re adequately hydrated can reduce fatigue throughout the day and during physical activity,” she says. 

It can also benefit your sleep, though the effects are mainly indirect, points out Angela Holliday-Bell, MD, a board-certified physician, certified sleep specialist, and CEO of The Solution is Sleep. “Rehydrating first thing in the morning can boost energy and decrease fatigue, making you more likely to get moving which can help with sleep,” she says. “And staying hydrated during the day can potentially decrease waking at night due to thirst.”

Myths About Drinking Water First Thing In the Morning

Hydrating at any time of day is important for optimal functioning, both mentally and physically. But some claims about drinking water first thing in the morning may be more hype than helpful.

Myth #1: It Helps Burn More Calories

“Drinking water in the morning won’t ‘kickstart your metabolism,’” Rizzo says. “Your metabolism works all hours of the day, even when you sleep.”

Of course, having a glass of water after waking up boosts hydration, “which plays a role in many bodily processes,” Rizzo reminds us. “But drinking water first thing in the morning without any other dietary or lifestyle changes will not lead to weight loss,” as some folks claim.

Myth #2: It Flushes Out Toxins

Nope, not so. Your kidneys and liver are the powerhouses of detoxification, working efficiently regardless of when you drink water. While hydration supports these organs, there’s no special “toxin-flushing” effect from drinking water in the morning versus any other time.

Myth #3: Water Needs to Be Cold to Have Maximum Impact

“There isn’t any research to show that drinking water first thing in the morning or drinking cold versus hot water makes a difference in overall health,” Rizzo says. “The only thing that really matters is making sure you get enough water throughout the day to stay hydrated.”

Surprisingly, your urine can help you monitor your hydration status. “When you wake up in the morning, you may notice that your first urine is dark yellow and has a low amount of output, which means you are dehydrated,” Rizzo says. “Keep sipping on water until you have to urinate and it’s a pale, yellow color—that indicates you are adequately hydrated.”

How Much Water Should You Drink In the Morning?

Generally, there aren’t any cons of starting the day with a glass of water. But how much should you actually drink?

Harris recommends a moderate amount of water first thing in the morning—about 8–16 ounces. “It’s a simple way to rehydrate after sleeping without overloading your bladder, which could interrupt your routine,” she explains. “A quick sip probably won’t do much, but a full glass strikes a nice balance to start your day feeling refreshed.” 

Rizzo agrees, adding that you can simply drink enough to “satisfy your thirst.” If you don’t feel thirsty, she recommends taking several sips or one to two big gulps to get some water in your system.

Drinking water first thing in the morning could ensure your hydration goals don’t get sidetracked once you’re out of bed. But if that’s too early, don’t sweat it—the exact timing shouldn’t matter too much. “You can also drink water with breakfast or with your coffee to make sure you are drinking it frequently throughout the morning and starting your day in a hydrated state,” Rizzo says.

And as a reminder, the US National Academies of Sciences, Engineering, and Medicine recommends that women aim for about 11.5 cups (3.7 liters) of fluids per day from both beverages and foods, while men should shoot for 15.5 cups (2.7 liters). Exercising and sweating may call for more water than that.

The Takeaway

Drinking water in the morning is a small habit that can pay off in a number of ways. It boosts hydration, improves cognitive function, aids the digestive processes, and reduces fatigue. It’s also a simple practice that can set a positive tone for the day. While it won’t significantly rev up your metabolism or “detox” your body as some may claim, drinking water first thing in the morning can serve as a small “win” that can kickstart other healthy habits once you’re out of bed.