Hydration and Sleep: Drinking Warm Water Before Bed

Time and again, you read about warm water in connection with hydration and sleep. But what’s the story behind it? Here’s a quick rundown of all the key information:

• Hydration plays an important role in our sleep.

• Poor sleep and dehydration are mutually reinforcing, creating a vicious cycle. If you sleep poorly, you become dehydrated more quickly—and if you’re dehydrated, your sleep quality declines.

• In the summer, high temperatures and potential allergies affect our sleep quality and cause us to become dehydrated even faster.

• You should drink about 35 ml of water per kg of body weight every day and avoid soft drinks and alcohol as much as possible to stay optimally hydrated.

• A warm glass of water supports your circulation and digestion, helps prevent dehydration, and promotes relaxation.

• At the same time, however, drinking before bed can also cause you to wake up at night and need to use the restroom.

• This condition, known as nocturia, isn’t just annoying—it can also cause long-term health problems.

• So if you already have to go to the bathroom frequently at night, it’s best not to drink anything right before bed.

More than 60% of our bodies consist of water. So it’s no wonder that hydration plays a significant role even during sleep, which is so important.

While we sleep, we (ideally) go over seven hours without drinking—longer than at any other time during the day. To prevent us from becoming too dehydrated during this time, our bodies release the hormone vasopressin during the late stages of sleep. It draws water from the primary urine, returns it to the body—and thus ensures that we essentially hydrate ourselves.

The problem: Good sleep is closely linked to our hydration levels; the worse we sleep, the higher the risk of dehydration. It’s a vicious cycle.

Study: Sleep Deprivation Leads to Dehydration

Astudy published in the * * by Pennsylvania State University examined the link between sleep deprivation and dehydration in 25,000 participants.

The result: Participants who slept less than six hours a day were significantly more likely to be dehydrated than those who got the recommended eight hours a day. Dehydration, even when mild, can cause cognitive, emotional, and physiological impairments that further worsen sleep.

As a result of this disrupted sleep, the body no longer releases the hormone vasopressin optimally—we become even more dehydrated and sleep even worse.

Typical symptoms that then occur include:

• Dry mouth

• Thirst

• Headaches

• Muscle cramps

To break this vicious cycle, we need to make sure we stay properly hydrated throughout the day. But more on that later.

Especially in the summer, it’s not uncommon for us to have trouble getting the rest we need at night. Two factors are primarily responsible for this:

• High temperatures: We normally loseabout 1.5 liters of sweat per night. In the summer, however, it can be even more—especially if it doesn’t cool down properly at night. This causes us to become dehydrated even faster.

• Allergies: The infamous hay feveralso affects our sleep. Pollen causes our noses to swell, forcing us to breathe more through our mouths—and thus dry out even faster. This is because the body uses even more water when it doesn’t get enough oxygen.

To prevent dehydration at night, you should make sure to stay well-hydrated throughout the day. You can easily tell if you’re sufficiently hydrated by checking your tongue and urine. A well-hydrated tongue appears moist and glossy, while your urine is clear or light yellow around noon. These signs indicate that your body has taken in enough water and your “water tank” is sufficiently filled. Pay attention to these simple but meaningful signals from your body to ensure that you’re always optimally hydrated.

Drink Enough Water

Make sure to drink about 35 ml of water per kilogram of body weight every day—more if you exercise a lot, are breastfeeding, or are sick.

If you find it difficult to drink enough water , these tips may help:

• Start your day with a glass of water right after you wake up.

• Use a water app that reminds you to drink regularly

• Always carry a reusable water bottle with you.

• Set clear hydration goals for yourself.

• Flavor your water with lemon, cucumber, or ginger.

• Always drink a glass of water with every meal.

• Make drinking a habit and tie it to your daily to-do list.

• Set a water reminder alarm or place Post-its in strategic spots.

Eat foods high in water content

Watermelons, pears, oranges, spinach, cucumbers, and citrus fruits have a high water content and help boost your fluid intake.

• Cucumber: Cucumbers are about 95% water.

• Watermelon: Watermelons have a water content of about 92%.

• Zucchini: Zucchini contain about 94% water.

• Tomatoes: Tomatoes are about 95% water.

• Strawberries: Strawberries have a water content of about 91%.

• Celery: Celery contains about 95% water.

• Lettuce: Lettuce has a water content of about 96%.

• Oranges: Oranges are about 87% water.

• Pineapples: Pineapples contain about 86% water.

• Peaches: Peaches have a water content of about 89%.

Avoid Caffeine and Alcohol

The caffeine in coffee has a diuretic effect. This means it stimulates the kidneys to excrete more water. For regular coffee drinkers, this effect is often less pronounced because the body becomes accustomed to the caffeine. In moderate amounts—about one to two cups a day—coffee generally has no significant negative impact on the body’s fluid balance.

Alcohol, on the other hand, has a much stronger impact on hydration. It acts as a potent diuretic by inhibiting the production of antidiuretic hormone (ADH). ADH is responsible for helping the kidneys retain water. When less ADH is produced, the body excretes more water, which in turn leads to increased fluid loss—and causes us to become dehydrated more quickly.

Both coffee and alcohol also disrupt sleep and result in generally poorer sleep quality.