More about Caffeine

Many of us start our days with a cup of coffee or tea. Caffeine does truly pick you up a little bit and make you even more alert. So particularly for people with routine tasks, it can be beneficial. For example, if you must drive a lot at nighttime, or if you are in the military and you are on duty to monitor, but nothing is really happening for hours on end.

How much caffeine we drink?

In fact, not everybody will need it. If you may have enough energy or get good enough sleep that you can go through the day without any caffeine.

Moreover, different people react very differently to caffeine.

If you are getting tremors, feeling suddenly nervous, or your heart rate is changing, it could well be that you are drinking too much caffeine. And it can interfere with a good night's sleep.

Your lifestyle also makes a difference. For example, if you are a smoker,  you metabolize caffeine in the liver about twice as fast, and so likely you can drink caffeine up to a later time and still be okay in terms of sleeping.

But there are other factors, like if you use oral contraceptives as a woman, it takes twice as long to metabolize caffeine and you may see that you cannot sleep well.

Genetics also plays a role, since some people have variants in their genetic code that affects enzymes in the liver that metabolize and get rid of the caffeine. This can make you metabolize it slower or faster, too.

In general, it is recommended by associations like the U.S. Food & Drug Administration to keep caffeine at 400 milligrams per day or less. If you look at a normal 8-ounce cup of coffee, that has about 100 milligrams of caffeine, so that would be up to four cups of coffee per day.

Another recommendation is to keep it to no more than 200 milligrams per sitting.