Most consider themselves to be either night owls or morning larks—those who prefer to stay up late or rise early. Now, people can identify with two more categories for preferred sleep schedules.
A study by Arcady Putilov and colleagues at the Siberian Branch of the Russian Academy of Sciences found that, in addition to larks and owls, people could be “high energetics,” who have high energy levels at morning and evening, or “lethargics,” who are tired both morning and evening, reports an article in The Atlantic.
For the study, which will be published in the journal Personality and Individual Differences, the biologists asked 130 people to stay awake for 24 hours. The subjects filled out questionnaires about how awake they felt, their sleep patterns and how well they had functioned during the previous week, the article notes.
The results showed that 29 were larks and 44 were owls, who went to bed about two hours later than the larks. The rest of the group, however, did not fall into either of these patterns, which led the biologists to categorize the high energetics and the lethargics.
Also, the energetics slept about a half-hour less overall than the other three groups, netting about 7.5 hours of sleep each night.
