Does drinking coffee or tea affect sleep quality? Does drinking tea make it difficult to fall asleep?

People who like to drink tea or coffee should look forward to sitting down and enjoying a cup of sweet tea or coffee after dinner every day to relax from the tense mood at work. However, many people are worried that drinking tea or coffee at night can easily make people feel energetic, but it is difficult to fall asleep and affect the quality of sleep. Is this really the case?

Caffeine in tea and coffee is the main substance that affects sleep

Both tea and coffee contain a substance called caffeine, which accounts for about 2% to 4% in tea and 1% to 2.2% in coffee.

When we drink tea or coffee, caffeine will cross the blood-brain barrier and bind to adenosine receptors, inhibiting their activity. Adenosine is at its lowest concentration when people go to bed in the morning. As people stay awake for longer and become more physically tired, the accumulated concentration of adenosine will become higher and higher. When the concentration of adenosine reaches a certain level, people will feel sleepy, and caffeine affects human sleep.

Caffeine has a wide range of effects on human sleep, including sleep latency, total sleep time, sleep efficiency, slow-wave sleep, and wakefulness. Caffeine can prolong sleep latency, lengthening the time it takes to fall asleep from lying down. It can also shorten total sleep time and reduce sleep efficiency, while reducing slow-wave sleep. This is the most important stage for the body to restore and consolidate memory. If this stage is shortened, the degree of physical recovery and memory will be affected. Caffeine can also increase "wakefulness," which reduces the quality of sleep.

Caffeine's effect on the human body is limited in duration

However, the caffeine in tea and coffee does not last as long as other stimulants or alcohol that stimulate the central nervous system. After caffeine is broken down in the liver and produces other initial metabolites, it can take effect within 1 hour.

If the amount of tea or coffee you drink is not too much, the effect will disappear in about 2 to 3 hours. In other words, if you drink a small amount of tea or coffee 2 to 3 hours before going to bed, the caffeine contained in it will hardly have any effect on your sleep. But if you drink tea or coffee within 1 hour before going to bed, it may affect the sleep of people who have low caffeine tolerance.

Caffeine's effects on sleep vary by age

The effect of caffeine on people of different ages varies. As the age of the drinker increases, the metabolic capacity deteriorates and the brain nerve activity decreases, so the tolerance to caffeine also decreases. Therefore, the reaction of the elderly to caffeine will be more obvious, and it will be more difficult for them to fall asleep after drinking tea or coffee at night.

To avoid being unable to sleep due to drinking tea at night, you can do this

For those who have the habit of drinking tea at night, there is also a little trick to avoid caffeine interfering with sleep quality. 50% of caffeine is released each time tea is brewed. Therefore, 50% of caffeine is released in the first brew of tea, and 25% of caffeine is released in the second brew of tea. At this time, 75% of the caffeine in the tea leaves has been released. By the third brew of tea, the remaining caffeine is very limited. People who are afraid that drinking tea will affect their sleep can start drinking from the third brew, which can avoid the problem of difficulty falling asleep due to excitement caused by caffeine.