DEAR DOCTOR K: I'm 40 years old and in good health. But lately I've been falling asleep suddenly during the day. What could be causing this?
DEAR READER: There are many things that can cause a person to fall asleep suddenly. Your sudden bouts of sleep might be caused by a rapid drop in your blood sugar, a side effect of a medication you're taking, or could result from stress, depression or inadequate sleep at night. Another possibility is narcolepsy.