It has long been thought that most people fall into one of two categories when it comes to sleep: morning people and night people. However, the British Psychological Society points to a small bit of research that suggests there might be more to it than that.
Photo by Pedro Riberio Simoes
In a small study being published in Personality and Individual Difference, researchers from the Siberian Branch of the Russian Academy of Sciences found that in addition to the traditional night owl or lark, people tend to have different energetic times of the day that might counter their sleep patterns. The BPS explains:
The researchers also identified two further chronotypes. There was a "high energetic" group of 25 people who reported feeling relatively sprightly in both the morning and evening; and a "lethargic" group of 32 others, who described feeling relatively dozy in both the morning and evening. Unlike the Owls and Larks, these two groups didn't show differences in terms of their time to bed and time of waking - their habits tended to lie mid-way between the Larks and Owls.
The researchers said their results support the idea of there being "four diurnal types, and each of these types can ... be differentiated from any of three other types on self-scorings of alertness-sleepiness levels in the course of 24-hours sleep deprivation."
So, if you've always found that you don't fit into the night owl or lark group, it looks like you might have an explanation. It's a small study of just 130 people, but the results could still help you find your more productive moments of the day.
You've Heard of Owls and Larks, Now Sleep Scientists Propose Two New Chronotypes [BPS Research Digest]