People consume caffeine (or coffee, to be precise) to kick-start their nervous system. Grabbing a cup of coffee while going to work is now habitual for most. As a downside, caffeine can also disturb the sleeping cycle. Therefore, it’s advised to not consume caffeine hours before going to sleep. But how long exactly it takes caffeine to wear off? In this article, we answer this intriguing question.
How does caffeine work?
Caffeine is an alkaloid and a stimulant found in many plant species. Coffee beans and cocoa beans are the primary sources. But they’re also found in tea leaves, kola nuts, guayusa, and 60 other plants.
When you consume food containing caffeine, the alkaloid breaks down and acts directly on your central nervous system. You’ll notice the most significant effects when it reaches your brain, and you feel more awake and alert.
These effects can take a few hours to materialize. Caffeine is absorbed from the stomach followed by the bloodstream, which then transports it to different parts of the body.
In the central nervous system, caffeine blocks a compound called adenosine from binding with the A1 receptors. This, if you know, causes sleepiness.
Besides that, caffeine also increases the heart rate and blood pressure to help you feel more awake.
How long does caffeine stay in the body?
Now that you know how caffeine works, you must be wondering how long it stays in the body. Multiple studies have researched this topic. One of the most cited ones is the one conducted by the American Academy of Sleep Medicine. As per the study’s results, caffeine’s half-life is about 5 hours.
Half-life is the amount of time it takes for a substance to be reduced to half its original amount.
So if you’re consuming 10 mg of caffeine in the morning, then expect it to stay in your body for 10 hours. Put it another way; you’ll have 5 mg of caffeine left in your body after 5 hours.
But you aren’t likely to stay energized for 10 hours. You’ll feel the effects of caffeine within half an hour of consuming it. Then once it reaches the liver, it is quickly metabolized. If consumed in the morning, you’ll have very little caffeine left in your body by evening.
The main noticeable event is sudden bursts of energy. You’ll feel more awake and jittery as coffee reaches its peak level. After a few minutes, you’ll feel the need to urinate. The more coffee you drink, the more intense the effects will be.
But 10 hours is just a benchmark. How long caffeine lasts in your body will also depend on dosages, BMI, age, tolerance, among other factors.
How much is too much caffeine?
USDA recommends 400 mg of caffeine as a safe dosage for a healthy adult. 400 mg of caffeine is roughly the same amount found in 4 cups of regular coffee. If it’s an energy shot drink, then it’s two cups.
Anything above this is considered too much. If you’re drinking too much, you’ll see symptoms like headache, nervousness, insomnia, abnormally frequent urination, irritability, among others.
People with caffeine sensitivity will feel the effects for several days. Therefore, it’s advised for them not to consume caffeine in any form.
Right time frame to drink coffee
Caffeine interferes with the central nervous system and hence influences sleep. Even in the afternoon hours, it can interfere with sleep to some degree.
Since the caffeine stays in the body for 10 hours from consumption, you should ideally not drink coffee 10 hours from going to bed. Morning is the best time to consume coffee, evening and night hours being the worst.
This a general rule that goes well for most people and easy to follow. As the caffeine concentration goes down, adenosine binds with A1 receptors once again.
This causes the muscles to relax and hence why you feel sleepy.
To sum up
Caffeine (read coffee/ristretto/espresso) is an excellent way to start your day. It can get you through a dull afternoon too. But it can break your sleep cycle if you consume it in the evening. That’s where you need to control your craving for coffee.
