From Science:
Do you tend to hit the snooze button on your alarm clock several times before getting out of bed? Does it take you forever, on certain days, to get yourself together before you leave the house? How many mornings have you decided that you need an extra cup of coffee just to get started, or an afternoon slug of espresso to make it through the day?
Do you ever take catnaps at your desk during lunch hour? Are there times when your patience runs so thin that you can barely listen to the stories of a colleague whose company you ordinarily enjoy? Do you recall snapping at your supervisor or your partner only to regret it moments–or days–later? Do you fall asleep in front of the TV when you come home from the lab? These can all be signs of a sleep deficit, which can cause a number of different problems if you choose to overlook them.
Recently, I attended a late-afternoon lecture given by a visiting scholar I had been looking forward to hearing. As the lights dimmed and he began his PowerPoint presentation, I felt my eyelids closing. As my chin fell onto my chest, I don’t know whether I was more startled or mortified. As I looked around to see whether the speaker or anyone else in the small group had noticed, my heart was pounding. The fear of a recurrence kept me vigilant for the rest of the lecture.
More here.