Early birds and night owls should prepare to welcome a few new birds to the sleep schedule flock, according to a group of Russian scientists.

A forthcoming study in the journal Personality and Individual Differences will present evidence for two previously unrecognized sleep patterns, The Atlantic reported: people who are energetic both morning and night, and those who are always sleepy.

As a Research Digest article on the study noted, "For many years, psychologists have divided people into two types based on their sleeping habits. There are larks who rise early, feeling sprightly in the morning, and retire to bed early; and owls, who do the opposite, preferring to get up late and who come alive in the evening."

The new chronotypes, or preferred sleep schedules, were determined by tracking energy levels of 130 study participants for around 24 hours.

"The participants were asked to refrain from coffee and alcohol, and several times during their stay they filled out questionnaires about how wakeful or dozy they were feeling," Research Digest reported.

Using questionnaire responses, the researchers determined that the group contained sleepers who didn't fit into the widely accepted lark and owl chronotypes, The Atlantic noted.

Although the findings could influence future sleep research, they're unlikely to alter people's everyday lives, The Atlantic reported. After all, it's an early bird world, and night owls rarely get to design their work days around their preferred sleep schedule.

As The New York Times reported in 2013, "few people have the luxury of organizing their lives by their chronotypes." That's why many men and women suffer from "social jet lag," which can occur when raising kids, attending an early meeting or taking a night class interrupt normal sleep patterns.

However, individuals can still benefit from being aware of their chronotype, because sleep schedules are related to quality of life and personal health issues, CBS News reported.

CBS News explored a recent study from researchers at the University of Barcelona, highlighting personality traits associated with early birds and night owls.

"Morning types are more resistant to fatigue, frustration and difficulties, which often translates into lower levels of anxiety and lower rates of depression, higher life satisfaction and less likelihood of substance abuse," CBS reported. "On the other hand, evening people tend to be more extravagant, temperamental, impulsive and novelty-seeking. … They are more likely to suffer from insomnia and ADHD."

To learn more about your personal chronotype, try this "Munich Chronotype Questionnnaire."

Email: kdallas@deseretnews.com Twitter: @kelsey_dallas