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Caffeine and Sleep: What's the Similarity?

Blog da SleepUp: Cafeína e sono

There's nothing more common than starting the day with a good cup of coffee! A coffee after lunch is also very traditional, almost a Brazilian habit. A common aspect of these two practices is the perception that coffee wakes us up and takes our sleep. In the first case, for making us wake up and start the day in a good mood; in the second, for pushing away that after-lunch sleep that we all feel. This feeling that coffee awakens us is also the basis for the growing consumption of caffeine pills, caffeinated energy drinks and caffeinated soft drinks in general.But after all, what is caffeine?

And is she really able to shake off sleep?

What is caffeine?

Caffeine is a natural substance, active principle of coffee, found mainly in the seeds of this plant. But several other plants also have this chemical substance, such as yerba mate (used to make chimarrão and tererê), cocoa, guarana, cola and tea. Note that all these plants are related to some beverage capable of awakening us.

FIGURE 1. A coffee plant (Coffea arabica). Caffeine is mainly found in its seeds. They are the ones that are dried, roasted and ground so that we can have our coffee. Source: Jmhullot -, CC BY-SA 3.0,

It is rapidly absorbed into the bloodstream and reaches peak levels in just 30 to 90 minutes and remains at a high level for 3-4 hours, which explains the duration of its effects. The main results of caffeine use are increased mental and physical performance. Even low doses are capable of increasing focus, energy, fat burning, alertness, and keeping us awake.

However, not all are wonderful: most of these effects are short, disappearing in at most a few hours. There are also some people who do not have these benefits. Finally, we must remember that there are several problems related to excessive caffeine consumption, such as increased blood pressure, anxiety attacks, heartburn and gastric ulcers, among others.

How does caffeine work?

Caffeine binds to adenosine receptors, which are located in your brain. Adenosine is a neuromodulator of the central nervous system and its main function is to tell the brain when we are fatigued.

During the day, as we spend energy, adenosine accumulates in the bloodstream and brain, making you feel sleepy. At the end of the day, the amount of adenosine reaches a peak that makes you die of sleep. With this, you sleep, precisely because sleep is the period necessary for you to regenerate all your energy sources.

Caffeine has the ability to bind to the same receptors as adenosine, inhibiting their activity and speeding up neural activity. It's as if caffeine “fools” the brain: no matter how much adenosine we have accumulated, caffeine blocks the receptors, causing the feeling of sleep and fatigue to momentarily cease.

What is the impact of caffeine on sleep?

With an effect of about 6 hours, your body will still be processing a cup of coffee you had in the morning, until late in the afternoon. When you increase your caffeine dose or consume it later, your sleep is negatively affected.

Adenosine receptors, which are supposed to help make you feel sleepy, aren't able to because they're blocked by caffeine. This will make you feel connected and alert, even if you were fatigued and at your usual bedtime. This is very similar to what happens to someone with insomnia.

For people with insomnia, caffeine can be a big problem, making a one-time problem a few nights chronic. It is known that caffeine consumption delays the onset of sleep, decreases total sleep time and increases the number of awakenings throughout the night. Caffeine can also completely restructure your sleep phases and reduce the amount of deep sleep, which is the critical phase for physical and mental rejuvenation.

For people with circadian rhythm disorders, caffeine can slow down the time on the body's internal clock, which signals the brain when it's time to go to sleep.

Is caffeine a good substitute for a bad night's sleep?

Caffeine should never be used to combat daytime sleepiness caused by a bad night's sleep. When you overdose on caffeine because of sleepiness, you start a vicious cycle of caffeine addiction and sleep deterioration. You feel unwell and fatigued from having slept poorly; then have a coffee to wake up. But this coffee, if overdone, could make the next night even worse.

You'll start to feel like you need more caffeine to function, which will make your sleep worse, generate side effects, and you'll likely develop a tolerance to caffeine.

Unfortunately, the answer to this cycle doesn't lie in another cup of coffee. It's about prioritizing your sleep, and then slowly and carefully reestablishing the habit.

What should you do so caffeine doesn't impact your sleep?

Don't be scared by everything that has been said here. It is completely possible to continue drinking your coffee and maintain a healthy sleep routine. To do this, follow healthy caffeine habits, such as taking the last dose within 2 pm and consuming no more than 250-350 mg per day. If your body does not tolerate caffeine well, reduce this amount and consume it sooner.

If you think you need a caffeine detox process, be aware that withdrawal symptoms will occur and you may feel worse before you feel better.

But don't worry, SleepUp can help you in this process of re-educating your sleep and eating habits! Enter our website, register, and be one of the first to receive our launch and promotion information!

#SleepUp #SleepUphealth #sleep #sono #insonia

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