Do you feel tired all the time? is sluggishness the reason for your low productivity? Is daytime sleepiness affecting your career and personal life? If you answer yes to any of these or all of these questions, you need to get your issue diagnosed by a doctor. The sluggishness you feel throughout the day could be because of an underlying sleep issue. It is hard to digest but sleep ailments are known to cause sluggishness or lethargic feeling which sometimes needs medications to get corrected. Nuvigil is one such drug you need to ward off sleepiness and to stay active throughout the day.