Why Does Coffee Make Sleepy?

Why Does Coffee Make Sleepy?

"Drink coffee to freshen up" is already our consensus, many people like to use a cup of coffee to start a new day. And after lunch and then a cup of coffee, sleep not only did not go away but more sleepy, have you experienced this? Have you ever wondered "am I drinking fake coffee?" "Am I "immune" to coffee"? "Is there something wrong with my body? "

So, why does drinking coffee cause Sleepy? Let's take a deeper look and hopefully solve your confusion.

Does caffeine make me tired?

Caffeine is the core active ingredient in coffee and is the world's legal and most consumed stimulant in the population. In addition to coffee, caffeine is also found in substances such as tea and cola. So, what exactly does caffeine do to the body? Here we start by reviewing the mechanism of caffeine's action.

Before talking about caffeine, let's meet a familiar and unfamiliar friend - adenosine (adenosine). Adenosine is a nucleoside that is found throughout the body and is mainly associated with the energy metabolism of living organisms. It is also an inhibitory neurotransmitter that promotes sleep. When it acts on different receptors, it can produce different electrophysiological effects, such as A1 receptors can reduce sinus node autoregulation and inhibit suppression of sinus node conduction, A2 receptors can cause vasodilation, A3 receptors are related to bronchoconstriction, etc.

Our protagonist, caffeine, acts mainly by antagonizing central and peripheral nervous system adenosine receptors. When it binds to the peripheral adenosine receptors, it can cause increased heart rate, accelerated metabolism, etc., causing increased oxygen demand, increased blood sugar, etc.; when it antagonizes the central receptors, it mainly shows the excitatory effect on the nervous system, i.e., increased alertness, enhanced coordination of thinking, etc.

Of course, caffeine is also a double-edged sword, and when used irrationally, including overconsumption and abuse, it can cause adverse effects on the human body, including insomnia, palpitations, tremors, gastrointestinal discomfort, cardiac arrhythmias, seizures, hallucinations, and psychiatric abnormalities. Current research suggests that a safe intake dose of caffeine is <400 mg/d for most healthy adults and <2.5 mg/kg-d for children and adolescents.

Why Does Coffee Make Sleepy?


Why does Caffeine Cause Sleepiness?

For healthy adults with unconventional caffeine intake, caffeine begins to take effect 30 minutes to 2 hours after intake and lasts for about 5 hours, although this varies by food type. Sleepiness following the consumption of caffeinated beverages may be related to the following factors:


1. Hypoglycemia

When consuming caffeinated foods with high sugar content, hypoglycemia may occur within a few hours after eating, mainly related to the increase in insulin secretion caused by high sugar and the subsequent drop in blood glucose levels, which in turn causes a lack of energy supply. sugar crash mainly manifests as feelings of fatigue, hunger, irritability, anxiety, headache, difficulty concentrating, sweating, tremor, etc.

Interestingly, a recent meta-analysis of the relationship between carbohydrates and mood showed that the body's alertness decreased within 60 minutes of eating carbohydrates and fatigue increased within 30 minutes and carbohydrates were not beneficial to mood, which contradicts the previous statement that "eating sweets makes you feel better".


2. Dehydrating effects

Caffeine is associated with frequent urination and increased urine output. When the body ingests caffeine, the diuretic effect increases, the water content in the blood decreases, and the blood circulation slows down, making the organ metabolism slower and the oxygen supply capacity decrease. When the brain's O2-CO2 metabolism slows down and carbon dioxide builds up, it can cause nervous system inhibition and a sense of unresponsiveness and sleepiness. On the other hand, caffeine has a vasoconstrictive effect, which can increase the resistance of blood circulation and cause aggravation of symptoms. If you repeatedly increase coffee intake at this time, it will not relieve the symptoms, but cause a vicious circle.


3. Caffeine withdrawal effects

As mentioned earlier, caffeine induces nervous system excitation mainly by antagonizing adenosine receptors, but the body can continue to produce adenosine, and when caffeine is metabolized, adenosine rebinds to the receptors, which can produce heart rate, metabolic slowdown, and deepening of sleepiness. Therefore, in the average individual, the metabolism of caffeine ends, and the body can return to normal rest. However, in individuals with long-term caffeine intake, adenosine receptors may be upregulated, and once caffeine intake is stopped, adenosine binding to receptors increases, resulting in increased inhibition of the nervous system, resulting in weakness, sleepiness, and depression, i.e., "caffeine withdrawal".


4. Body vitamin B levels

Metabolism requires the consumption of vitamin B. When vitamin B is sufficient, people do not easily feel fatigued, or can easily recover from fatigue. Conversely, when vitamin B is more deficient, it is easy to feel sleepy.

Caffeine also needs to be metabolized to be excreted from the body. If your recent vitamin B intake is not enough, when you are very tired, there is a lot of accumulated waste in the body to be metabolized, plus caffeine, the body will not be able to function properly, the phenomenon of "drink coffee more want to sleep"!


How to Avoid It?

Caffeine-induced sleepiness is individual-specific and is related to body tolerance, type of food, and combined medications. The simplest and easiest ways include.

➤ Avoid foods with high caffeine content. High caffeine intake is prone to fluctuate levels of the transmitter in the body and to various side effects.

➤ Maintain caffeine levels in the body. Maintain caffeine levels by dividing and dividing intakes, such as quoting coffee in the morning and switching to tea with lower caffeine content in the afternoon, avoiding bedtime intake, and maintaining normal body work and rest.

➤ Avoid intake of caffeinated beverages with high sugar content. Avoid "sugar crash".

➤ Drink more water. Ensure blood circulation and energy supply.


How to consume caffeine properly

-Choosing Decaf

If possible, people with poor caffeine metabolism should try to choose decaf coffee. decaf is coffee with less than 0.1% caffeine, not completely caffeine-free, its production process uses a safe and non-toxic organic solvent to remove caffeine from coffee but retains the main flavor components of coffee.

-No fasting

Food in the stomach slows down the absorption of caffeine and reduces its irritation to the stomach. In this way, the absorption of caffeine slows down but does not reduce the effect or duration of caffeine action.

-Drink milk coffee

Lattes, cappuccinos, and mochas have more milk added to them, which slows down the absorption of caffeine and stimulates the stomach less. Conversely, drip coffee and espresso are high in caffeine and need to be avoided.

-Drink only in the morning

People with poor coffee metabolism should avoid drinking coffee in the afternoon and evening, as this may interfere with sleep at night.


The Bottom Line

It is true that the phenomenon of being "sleepy after drinking coffee" exists, but it does not mean that drinking coffee makes you sleepy easily. If you feel drowsy after each coffee, it is recommended to suspend drinking and drink tea or other beverages instead.

In addition, if the body is in a state of extreme fatigue, we have more caffeine will not help. What we need to do at this time is to rest well and protect our bodies to better enjoy the goodness of coffee.

After all, many factors make people tired, caffeine can not help us solve them.


Frequently Asked Questions

-How long does caffeine stay in the body?

Half of the time that caffeine is metabolized is about five to six hours. This means that after five or six hours there is still 50% of the caffeine circulating in our body. In addition, a quarter of the time that caffeine remains in the body is about ten to twelve hours.


-Can drinking coffee cause osteoporosis?

Caffeine itself has a very good diuretic effect, if long-term and large amounts of coffee, are easy to cause bone loss, the preservation of bone mass will hurt women, and may increase the threat of osteoporosis. But the premise is that the usual lack of food intake of sufficient calcium, or people who do not move often, plus women after menopause, due to the lack of estrogen caused by the loss of calcium, these cases plus a large amount of caffeine, before the bone may pose a threat.

A normal diet and proper exercise will not lead to bone fragility.


-Does drinking coffee affect your heart?

If you already have high blood pressure, using large amounts of caffeine will only make your situation worse. Because caffeine alone can make blood pressure rise, if combined with emotional stress, it will produce a dangerous multiplier effect, so people at risk of high blood pressure should especially avoid drinking caffeinated beverages when they are under stress at work.

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