It seems like everybody these days is running on fumes – and far too little sleep. It's not at all unusual for drivers to turn to a little caffeine for assistance waking up when they're feeling drowsy or fatigued.

Unfortunately, even the biggest cup of coffee isn't really up to the job. 

You can't fight sleep deprivation with caffeine

It's true that caffeine is a stimulant, and the combo of increased dopamine production, adenosine blockade and adrenaline that it causes will make you feel more alert – for a while. But a lot of people find that the effect of caffeine is very transitory. As soon as the caffeine runs its course, you “crash” and feel more fatigued than ever. Subsequent cups of coffee or doses of energy shots will usually produce diminishing returns, too.

In addition, even that temporary sense of alertness doesn't translate into “fully functioning.” In a recent study, sleep-deprived participants were given caffeine and asked to complete two different tasks, one easier than the other. While the caffeine seemed to help participants complete the easier task, it did nothing for them when it came to the one that required more concentration. 

In other words, caffeine can get you through a task you can safely do “on automatic,” but it doesn't really help at all when it comes to your performance on tasks that require you to pay close attention to your movements and what's happening – like when you're driving.

Take care of yourself and your loved ones out there this holiday season, and avoid driving while fatigued. It's better to get to your destination a little later than you intend than not at all.