* In certain instances, taking a longer nap of 90 minutes to 2 hours may make sense. Extended naps mimic, for both the brain and the body, what occurs during nighttime sleep. Unfortunately, longer naps can also interfere with nighttime sleep, which is far more important. Therefore, most experts only recommend extended naps for individuals who genuinely need the additional deep sleep during the day, in that it doesn't interfere with their nighttime sleep. Elite athletes completing grueling two-a-day workouts are a good example of a group that could stand to benefit from longer naps. The famed American distance runner Meb Keflezighi says he uses a full arsenal of naps ranging in duration from 15 to 90 minutes.