Effects of circadian typology on sleep-wake behavior of air traffic controllers.

The effects of circadian typology on sleep-wake behavior in shiftworkers were investigated using wrist actigraph in 18 air traffic controllers (ATC), nine morning types and nine evening types, working in a backward 1-1-1 super rapid rotation shift schedule. The ATC wore a wrist actigraph continuously over 6 days (3 days on duty and 3 days off duty). Evening types presented more flexible sleep habits and slept significantly less than morning types. Regardless of circadian typology, the morning shift tended to reduce the amount of sleep whereas night shift produced a decrease in daily activity.