NEW: Another air controller naps; new schedules coming

WASHINGTON (AP) - The government is changing air traffic controllers' work schedules following another incident of a controller falling asleep on the job.

The Federal Aviation Administration says it happened early Saturday morning at a radar facility in Miami that handles high altitude air traffic. A controller fell asleep while on duty.

The FAA says 12 other controllers and two managers were working at the time. The sleeping controller has been suspended.

FAA chief Randy Babbitt says changes will be made to work schedule that have been identified as most likely to cause fatigue within 72 hours.

Reports of sleeping air traffic controllers highlight an often-ignored fact: Workers on night shifts have trouble concentrating and staying awake. The chief of sleep medicine at Brigham and Women's Hospital in Boston, Dr. Charles Czeisler, says people routinely fall asleep when working at night.

He says studies show that 30 to 50 percent of night-shift workers report falling asleep on the job at least once a week.

The danger isn't limited to air traffic controllers. It can happen to pilots, truck and bus drivers, nurses and doctors, police and firefighters -- anyone who works at night or has changing shifts.

A neuroscientist at the City University of New York, Dr. William Fishbein, says when people work odd shifts "it mucks up their biological rhythms." He says hormones are synchronized with the wake-sleep cycle. When people change shifts, the brain doesn't know when it's supposed to be asleep.

Along with drowsiness and trouble concentrating, people working at night are more likely to have chronic intestinal and heart diseases and some forms of cancer. The World Health Organization has classified shift work as a probable carcinogen.

(Copyright 2011 by The Associated Press. All Rights Reserved.)