Researchers at the University of Toronto asked more than 700 people about their preferred time of day and how healthy and happy they generally feel.
They then compared the responses of the group of younger adults aged 17 to 38 with older people ages 59 to 79.
Only about seven per cent of young adults are morning larks, while by age 60 most people preferred to be up with the dawn. Just seven per cent of the oldest people in the study described themselves as night owls.
"We found that older adults reported greater positive emotion than younger adults, and older adults were more likely to be morning-type people than younger adults," study researcher Renee Biss from the University of Toronto reportedly told LiveScience. The "morningness" was associated with greater happiness emotions in both age groups.
Morning types also tended to report that they felt healthier than the late risers, according to the study that published in the journal Emotion. The researchers said that this apparent health benefit could come from the extra sleep they would enjoy, as their sleeping schedule would fit with society's expectations of rising early for work.
This extra sleep could not only make them feel more alert, but may also boost their immune system.额外的睡眠不仅会让他们更加清醒，而且还能提升他们的免疫系统。
"Evening people may be more prone to social jetlag; this means that their biological clock is out of sync with the social clock," Ms Biss said. "Society's expectations are far more organized around a morning-type person's schedule."“‘夜猫子’则更容易面临社交时差；也就是说他们的生物钟和社会时钟脱节了，” 比什女士说。“社会预期更多的是围绕着‘早起鸟"的日程安排。”
"An evening person may go through their week feeling unhappy because they have to get up earlier than they would like to." But Ms Biss said there was hope for night owls as it was possible for them to turn themselves into morning people.
"One way to do it is to increase your natural light exposure early in the morning, and to wake up earlier and go to bed earlier," she said."It's easiest if you have a consistent schedule, to make sure you are waking up at the same time every day."