to 11 p.m., the early morning types would feel worse than evening types," said Kristen Knutson, an associate professor at Northwestern University, who researches the association between sleep, circadian rhythms and cardiometabolic diseases, including diabetes, obesity and cardiovascular disease.
"The underlying mechanism is our internal biological clock that dictates the time of day we perform best," said Knutson, who wasn't involved in the research."For example, the employee who seems like a slow starter in the morning might be the person who's most able to work effectively into the evening to meet an important deadline," said Hood, who wasn't involved in the research."If there is some opportunity for flexibility in scheduling, allowing employees some control over what time of day they complete their work may help to optimize performance and productivity."However, she said there was lots of evidence to show "that chronotype can affect your cognitive sharpness, which can play into performance on the job or in the classroom.""This influence is clear when you challenge someone to pay attention and remember information at a time of day outside of their preference: for example, asking an evening person to deliver an important presentation to clients at a 7:30 a.m.