Washington, Apr 24 : Early birds may be chirpier in the morning, but it's the night owls that score over them when it comes to being alert after waking up from sleep, concludes a new brain-scan study.
In the study, researchers monitored the brain activity of self-described early birds and night owls in a sleep lab.
Led by Christina Schmidt of the University of Liege in Belgium, the researchers also took hourly saliva samples to measure the sleepers'' levels of melatonin-a hormone thought to help naturally regulate sleep cycles in mammals.