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For those who have recently had trouble falling asleep and want to improve their sleep by knowing what drinks are good to have before bed, this article explains recommended drinks before bed and drinks that should be avoided.
How many hours before bed is ideal for drinking?
First, we will explain why hydrating before sleep can improve sleep quality and recommend the best times to drink.
Lowering core body temperature is key
When a person falls asleep, blood flow inside the skin increases, raising the body's surface temperature (skin temperature). Heat is then radiated from the skin, which lowers the body's internal temperature (core body temperature).
When core body temperature decreases, melatonin hormone secretion becomes active, shifting the body into sleep mode. Furthermore, a decrease in body temperature relaxes the brain, making it crucial to lower core body temperature for quality sleep.
Warm drinks 1 to several hours before sleep
People feel sleepy when their core body temperature drops, and the greater the difference between skin temperature and core body temperature, the stronger the feeling of sleepiness, leading to better sleep quality. Therefore, it is recommended to drink a warm beverage 1 to several hours before bed to raise your core body temperature. The core body temperature tends to drop as much as it rises, making it easier to fall asleep naturally.
Room temperature or cold drinks just before sleep
To achieve high-quality sleep, it is necessary to lower your core body temperature, so just before bed, opt for room temperature or cold drinks instead of warm ones. However, be careful as excessively cold drinks can put a strain on your stomach and intestines. Drinking slowly can help alleviate this strain.
Also, if you are concerned about needing to use the restroom at night, finish hydrating at least an hour before bed, rather than right before.
What is the ideal amount to drink before bed?
It is said that "people sweat one to two cups of water while sleeping." While sweating during sleep is a normal physiological phenomenon that deepens sleep, not hydrating before bed can lead to dehydration or insufficient fluid for body temperature regulation through sweating, thus deteriorating sleep quality.
However, drinking too much can cause you to wake up multiple times during the night to use the restroom, so aim for about one glass (250 ml).
Recommended drinks before bed
To enhance sleep quality, it's best to warm your body first and then allow your core body temperature to drop. Therefore, drinking a warm beverage 1 to 2 hours before bed is recommended. Here are 6 drinks to consider before sleep.
1: Hot milk
Milk contains tryptophan, which is a raw material for producing the sleep hormone melatonin, so it can promote restful sleep. Additionally, the calcium abundant in milk is also expected to suppress the sympathetic nervous system (active mode) and promote the parasympathetic nervous system (relaxed mode).
Furthermore, milk is easy to digest and absorb, making it an excellent choice before bed.
2: Hot cocoa
Cocoa contains a component called theobromine, which helps regulate the autonomic nervous system, improve the onset of sleep, and deepen sleep, thus enhancing sleep quality. Consuming a lot of sugar before bed raises blood sugar levels and can decrease sleep quality, so choose pure cocoa without added sugar or milk, rather than sweetened cocoa or milk cocoa.
Cocoa that already contains milk often has a high sugar content, so it's better to avoid it. However, adding milk to pure cocoa is recommended. The tryptophan (an amino acid) and calcium in milk can provide a relaxing effect and promote high-quality sleep.
Cocoa mixed with milk helps produce melatonin, a sleep hormone, thereby promoting restful sleep. However, melatonin is generated 1 to 2 hours after drinking cocoa, so drink it 1 to 2 hours before bed, not immediately before.
*Pure cocoa also contains a very small amount of caffeine, so please be careful not to consume too much.
3: Herbal tea
Some herbs have relaxing effects and can regulate the autonomic nervous system, thereby improving sleep quality. Most herbs do not contain caffeine, which has an awakening or diuretic effect, so you can safely drink them right before bed.
However, some herbs should be avoided during pregnancy due to their physiological stimulating or uterine contracting effects, so please consult your doctor.
Representative herbs effective for quality sleep include "chamomile" and "orange blossom" for insomnia, anxiety, and stress; "lavender," which is said to have calming and antidepressant effects; and "rose," which calms emotions and mood.
4: Hot ginger
Hot ginger, made by adding ginger to hot water, can be prepared by slicing fresh ginger yourself, or by purchasing powdered or tube ginger. Ginger is expected to improve blood circulation and warm the body, so it is recommended to drink it 1 to 2 hours before bed.
However, be careful as adding too much ginger can put a strain on your stomach and intestines.
5: Plain hot water
Drinking plain hot water warms the body from the inside, which is said to promote the parasympathetic nervous system for sleep mode and have a relaxing effect. Furthermore, drinking it slowly over time can enhance relaxation.
6: Amazake (sweet sake)
Amazake contains GABA, known for its stress-relieving properties, which can help calm the mind and promote restful sleep. Warming amazake can further enhance relaxation, but be careful not to overheat it as enzymes and B vitamins in amazake are sensitive to heat; aim for below 60 degrees Celsius.
Also, amazake made from rice koji often contains a lot of carbohydrates, so be careful not to drink too much. It is recommended not to exceed 200cc per day, so if you also drink it in the morning, it is advisable to spread out the amount per serving.
NG drinks to avoid before bed
Be careful of drinks that can negatively impact your sleep quality if consumed before bed.
Caffeinated drinks
Caffeine, found in large amounts in coffee, black tea, and green tea, obstructs the action of adenosine, which induces drowsiness, thus blocking sleepiness. While moderate consumption is fine, excessive intake can lead to sleep disorders like insomnia.
Furthermore, caffeine has a diuretic effect, which might cause you to wake up during the night to use the restroom. Caffeine reaches its peak blood concentration 30 minutes to 1 hour after consumption and its blood concentration halves in 4 to 6 hours, so avoiding caffeine at least 6 hours before bed can help prevent a decrease in sleep quality.
Incidentally, among teas, Gyokuro contains more caffeine than coffee, so caution is advised.
- Caffeine in Gyokuro: approximately 160mg per 100ml
- Caffeine in Sencha: approximately 20mg per 100ml
- Caffeine in coffee: approximately 60mg per 100ml
- Caffeine in black tea: approximately 30mg per 100ml
- Caffeine in Oolong tea: approximately 20mg per 100ml
Alcohol
While many studies show that a small amount of alcohol can help with falling asleep, a large amount of alcohol is a major enemy of sleep. Even if it helps you fall asleep, it tends to increase the number of times you wake up during the night and shorten your sleep duration, thus degrading the quality of your sleep.
Additionally, drinking alcohol before bed can relax the muscles that keep the upper airway open and worsen airflow in the nose and pharynx, making it easier for breathing to stop during sleep.
Since the duration of apnea becomes longer, there are concerns about its impact on sleep apnea syndrome. If someone who habitually uses alcohol to sleep stops drinking, they might experience difficulty falling asleep, and this insomnia can become chronic, so it is recommended to consult a medical institution.
To achieve restful sleep
If you're having trouble falling asleep or feeling that your sleep is light, try drinking the beverages mentioned before bedtime. In addition to knowing what to drink before bed, paying attention to your sleeping environment, such as bedding, can also lead to higher quality sleep. So, why not look for bedding that suits your preferences?
【Reference】
※ Standard Tables of Food Composition in Japan 2020 (Eighth Revised Edition)
