This piece of advice is a bit backwards, but it doesn’t hurt to try. If you want to keep yourself awake, the best way to do it is have a cup of coffee followed immediately by a 15-minute nap.
This method was recommended by sleep researchers at the Loughborough University in Britain, who tested many different ways to keep sleep-deprived drivers alert. Researchers found coffee helps clear your system of adenosine, a chemical which makes you sleepy. So in testing, the combination of a cup of coffee with an immediate nap chaser provided the most alertness for the longest period of time. The recommendation was to nap only 15 minutes, no more or less and you must sleep immediately after the coffee.
[ via Achieve-IT! ]