Why do some people suffer from insomnia after drinking tea or coffee, but others do not?

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Insomnia Caffeinated Substances Sleep Cycle Tea

Coffee REM sleep light sleep biological rhythm

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Why do some people suffer from insomnia after drinking tea or coffee? This has to do with the source of caffeine.

You may have met some people in your life who say that caffeine is harmful to health, so they don’t drink coffee and only drink tea...

In fact, whether you drink coffee or tea, it will stimulate the central nervous system and has a certain diuretic effect . It is a common cause of insomnia and is also addictive.

01The Origin of Caffeine

German chemist Friedrich Ferdinand Runge extracted caffeine from coffee beans in 1882, and a few years later, he extracted the same ingredient from tea leaves. At that time, he named this ingredient "theaine". Later, these ingredients of different origins were uniformly named "caffeine".

Just imagine, if Runge's experiment had succeeded a few years later, we might have called "caffeine" "tea".

So how does caffeine affect sleep?

0 2 Sleep Cycle

The sleep cycle refers to a biological rhythm of sleep, which is divided into 5 stages. Usually, after turning off the lights, we need 15% to 20% of the time to enter the first stage of sleep;

Rapid eye movement sleep is the end of the sleep cycle, accounting for 20% to 25% of sleep time, with the lowest muscle tension and dreaming.

In the first stage we may feel drowsy, have reduced muscle activity, and may experience hypnagogic hallucinations.

In the second stage, we will enter a light sleep, which is difficult to wake up and we will lose our response to the external environment.

In the third and fourth stages, we will enter deep sleep, which accounts for 15% to 25% of our sleep time. This is best for relieving fatigue and consolidating memory.

These five phases form a cycle, and each cycle lasts about 90 minutes.

Healthy sleep requires 4 to 6 cycles. No matter which cycle of sleep is interrupted, it may affect our concentration, causing emotional instability and damaging long-term health.

03 The BBC's Ten Rules of Sleep conducted such an experiment;

Volunteer Holly Shire drank three cups of coffee a few hours before bed and spent the night in a sleep laboratory at the University of Surrey, where sleep experts monitored Holly's sleep.

Her brain waves will be monitored throughout the night to see what effects the drinks she consumes have on her sleep.

The next day , according to Holly's brain waves, coffee made it difficult for her to fall asleep; at the same time, the time of light sleep became longer, while the time of deep sleep became less, and Holly was unable to get enough rest.

Therefore, caffeine intake will prolong the time it takes us to fall asleep. At the beginning, deep sleep is suppressed and the number of awakenings may increase.

Caffeine is a stimulant that speeds up breathing and heartbeat, increases blood pressure, increases energy, and reduces the secretion of melatonin. The effects of caffeine last for 14 hours.

04 Substances containing caffeine;

Caffeine is commonly found in coffee, cola, tea, and some over-the-counter drugs (such as cold medicines and anti-allergy drugs) . Caffeine can block adenosine receptors and cause cortical arousal. Taking 300 mg of caffeine at a time can reduce REM sleep (rapid eye movement sleep), and taking 500 mg is equivalent to the arousal caused by 5 mg of amphetamine.

What does 300mg of caffeine mean?

Coffee and tea are both common hobby drinks. Because everyone has different brewing methods and preferences, the brewing concentration varies greatly. If brewed according to the method sold on the market :

• Coffee: 120cc of coffee generally contains 60~100mg of caffeine, which is the same as the caffeine content in a cup of espresso (30cc).

• Tea: 120cc of sencha contains 20mg of caffeine, and 120cc of black tea contains 30mg of caffeine.

So how much caffeine is harmful to the body?

In my opinion, this is a pseudo-question; because everyone's physique, physical condition and weight are different, the conclusion cannot be generalized. Coffee or tea is just a hobby drink, as long as it tastes good and makes you happy, that's enough.

PS: Using caffeine before bedtime or drinking too much coffee during the day will increase your energy and wakefulness, making it difficult to fall asleep, so try to drink less caffeinated drinks after 4 p.m. For people with insomnia, it is best to stay away from caffeine.

References | "BBC Ten Rules of Sleep"; "You Don't Know Coffee";

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