First, in response to a post a few up from this, aspirin does not contain caffeine, Excedrin does. Excedrin also contains aspirin and acetaminophen. I personally avoid it, and take either acetaminophen by itself or with just plain aspirin. The reason I do this is because while it initially helps make the headache go away, caffeine will actually make it worse long term.

To answer those people wondering about the purpose of the nap, or having questions about the specific time line of events for a caffeine nap, the nap is to allow yourself a small amount of sleep to help refresh yourself somewhat before you begin the extended period of being awake. It’s just like a power nap. The reason for the 15 minutes (in a research article I read last year I believe it said 30 minutes) is because that is approximately how long it takes the caffeine to start having its effects. You go to sleep right after, while you still can, and you get as much sleep as you can until the caffeine starts waking you up. Keep in mind, of course, it may not wake you on its own, especially if you’re very tired, so unless you set an alarm, you may have just taken in high amounts of caffeine for no reason. As far as when to start the timer, I’d say as soon as you start drinking. At that point the caffeine is making its way into your system and the countdown is beginning. Obviously, the faster you drink a cup of coffee or an energy drink the faster it will start impacting you, and it will be more sudden. The slower you drink it, the slower and more gradual it will be. If you take 15 minutes to drink it, you may not be able to get a nap in.

Another thing to keep in mind is that caffeine has detrimental effects on sleep quality, so when you do sleep when you’re finally done studying or whatever it is you’re staying up for, it won’t be as refreshing as it otherwise would be. This is also, at least partly, why it has the effect on dreams that some people commented on. It disrupts the sleep cycle, preventing you from entering deep sleep as much, so you spend more time in REM sleep, which is when you dream. Alcohol has the same effect.

Another thing, in fact the main thing it was about, the research article I read mentioned was that glucose (sugar) and caffeine combined are more effective at maintaining mental alertness and efficiency than either one on their own. So adding a little sugar to coffee or, in my case, drinking energy drinks (mainly because coffee is hard on my stomach the following day) is even better for late night studying. And as long as you only have one, maybe two and only do it occasionally, it’s very unlikely it’s going to cause any problems. For example, I never drink soda/pop, and every now and then when I’m pulling a late night of studying I’ll have an energy drink (very rarely I’ll have two). Compared to the caffeine consumption of regular coffee or soda/pop drinkers, I feel very comfortable with my level of intake. Drinking high doses, as in one or two every day or more than three or so at a time, has been linked to seizures, but it’s pretty uncommon, and I don’t drink even close to what would even be considered marginal. As with anything else, it’s about being smart and maintaining a common sense limit.

Also as with anything involving your health, if you’re concerned about it (which I hope you are), you should do your own research, even if it’s just talking to your doctor. I hope I’ve been able to clear things up for everyone and answer some of your questions.