Maybe your habit extends to a cup of coffee in the afternoon, or you have a soda with your dinner.
And maybe as a result, you lay awake later and thought about where you went wrong instead of getting the sleep you needed.
Rob M. van Dam, a researcher in epidemiology and nutrition from the National University of Singapore, explains when to wisely consume caffeine, what qualifies for too much, and what to know about why it affects each of us differently .
This interview has been condensed and edited for the sake of clarity.
CNN: How do we know when it’s time to stop drinking coffee a day so we can still get a good night’s sleep?
Rob van Dam: It sounds like a simple question, but unfortunately there is no answer to it. And that’s because different people react very differently to caffeine.
If you get shaking, suddenly feel nervous, or your heart rate changes, you may be drinking too much caffeine. And similarly, it can interfere with a good night’s sleep.
You might say, “Well, let’s try cutting down on caffeine and not drinking it after a certain time in the afternoon and see if it improves my sleeping habits.” So it’s really something every single person has to experiment with themselves – how much caffeine they drink and when they drink it.
CNN: What factors affect how we react to caffeine?
From dam: Your lifestyle makes a difference. For example, people who smoke metabolize caffeine in the liver about twice as fast. If you smoke, you can probably drink caffeine up to a later date and still be okay in terms of sleeping.
But there are other factors that if you use birth control pills as a woman, it takes twice as long to metabolize caffeine. It may be that you were able to drink caffeine in the evening and still sleep well, and then you start using oral contraceptives and you can see that you can no longer sleep as well.
Genetics also play a role, as some people have variations in their genetic code that affect enzymes in the liver that metabolize and get rid of caffeine. This can make you metabolize it slower or faster too.
CNN: How much caffeine is too much?
From dam: Generally, it is recommended by associations such as the US Food & Drug Administration to keep caffeine at 400 milligrams a day or less. If you look at a normal 8 ounce cup of coffee that has approx. 100 milligrams of caffeine, so that would be up to four cups of coffee a day.
Another recommendation is to keep it at a maximum of 200 milligrams per. Meet. Although you may drink four cups a day, you will not drink four cups at once – it will be too much for the body to metabolize, at least for most people.
CNN: Is Caffeine for Everyone?
From dam: Caffeine really picks you up a bit and makes you even more aware. So especially for people with routine tasks it can be an advantage. For example, if you have to drive a lot at night, or if you are in the military and you have a duty to monitor but nothing happens for hours.
But not everyone needs it. You may have enough energy or get good enough sleep so you can go through the day without caffeine.
And there’s no need to drink it if you don’t want to. Because even if you like the taste of coffee, you can always drink decaffeinated coffee, and there is nothing wrong with that either.
CNN: Is Caffeine Safe?
From dam: Recently, people have been very concerned about caffeine in relation to cancer risk, cardiovascular risk or other health outcomes. And the research on it has actually been very reassuring. At present, coffee is probably one of the most researched beverages.
So if you enjoy coffee, you enjoy caffeine, and you can consume it in moderation, and you have no harmful effects – you do not really have to worry too much about the health effects of coffee or caffeine.