Maybe your habit extends to an afternoon cup of coffee, or you have a soda with your dinner.
And maybe as a result, you later lay in your bed awake thinking about where you went wrong instead of sleeping.
Rob M. van Dam, Epidemiology and Nutrition Researcher at the National University of Singapore, explains when to consume caffeine wisely, what is considered too much, and what to know about why it affects each of us differently.
This interview has been condensed and edited for clarity.
CNN: How do we know when it’s time to stop drinking coffee during the day so that we can still get a good night’s sleep?
Rob van Dam: It sounds like a simple question, but unfortunately there isn’t just one answer. And that’s because different people react very differently to caffeine.
If you experience tremors, suddenly feel nervous, or have a change in your heart rate, you may be drinking too much caffeine. And likewise, it can interfere with a good night’s sleep.
You might want to say, “Well let’s try cutting down on the caffeine and not drinking it after a while in the afternoon and see if that improves my sleep patterns. So this is something that each individual should experience for themselves: how much caffeine they drink and when they drink it.
CNN: What factors affect our response to caffeine?
From the 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 later on and still be able to sleep.
But there are other factors, like if you use birth control pills as a woman, it takes twice as long to metabolize caffeine. You may have been able to drink caffeine at night while sleeping well, then you start using birth control pills and you may find that you can’t sleep as well anymore.
Genetics also play a role, as some people have variations in their genetic code that affect liver enzymes that metabolize and eliminate caffeine. It can also cause you to metabolize slower or faster.
CNN: How much caffeine is too much?
From the dam: In general, it’s recommended by associations like the United States Food & Drug Administration to keep caffeine at 400 milligrams per day or less. If you look at a normal 8-ounce cup of coffee, which has around 100 milligrams of caffeine, then that would be up to four cups of coffee per day.
Another recommendation is not to exceed 200 milligrams per session. Even though you can drink four cups a day, you don’t want to 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 the dam: Caffeine really lifts you up a bit and makes you even more alert. So, especially for people with routine tasks, it can be beneficial. For example, if you have to drive a lot at night, or if you are in the military and you are on duty to watch, but nothing really happens for hours.
But not everyone will need it. You can have enough energy or sleep well to get through the day without caffeine.
And there’s no reason to drink it if you don’t want to. Because even if you like the taste of coffee, you can still drink decaffeinated coffee, and there’s nothing wrong with that either.
CNN: Is caffeine safe?
From the dam: Recently, people have been very concerned about caffeine for cancer risk, cardiovascular risk, or other health issues. And the research on this has actually been very reassuring. Coffee is probably one of the most studied drinks today.
So if you enjoy coffee, you enjoy caffeine, you can consume it in moderation, and you don’t have any ill effects – you don’t really have to worry about the health effects of coffee or coffee. caffeine.