DEAR DOCTOR K: I'm a nurse, and I can be assigned to work the day shift, evening shift or night shift. I hear that shift workers can develop health problems. What is known about that?
DEAR READER: More than 9 million people in the United States are shift workers like you. Studies show that nearly 10 percent of night-shift workers have severe reactions to that schedule. Some become overwhelmingly sleepy during the night shift, when they need to be alert. Some have trouble concentrating and focusing on a task. Others can't really fall deeply asleep during the day, when they need to get some sleep.