Why Are You Tired All the Time?


For years, sleep scientists have spoken about “owls” and “larks” when dividing people into the two commonly accepted types of people with distinct sleeping habits. Apparently it’s time to add two new types to the list. Larks are people who get up early and similarly, go to bed early. Owls, on the other hand, prefer to get up late and stay up just as late.

There are however, lots of people who seem not to fit these two cookie-cutter types, identifying themselves neither as a morning person nor a night person. Many healthy individuals often feel sluggish or alternatively, constantly full of energy. This phenomenon has now been analyzed in a new study published by Arcady Putilov at the Siberian Branch of the Russian Academy of Sciences.

As part of the study, researchers kept 130 men and women awake for 24 hours, in a sleep lab. The subjects were told to refrain from consuming caffeine or alcohol. They were repeatedly, at different times, asked to fill out questionnaires about their feelings of alertness or fatigue. They were also asked to report about their sleeping habits in general and from previous days.
Analyzing the subjects’ energy levels throughout the 24 hour period alongside the information they provided, helped Putilov identify four unique types of sleeping personalities.

The already familiar type, the larks, showed higher energy levels at 9:00 AM and lower levels at 9:00 PM and midnight. The owl type displayed the opposite. However, two additional groups were identified from among the patterns. There existed a “high-energy” group of 25 individuals that reported feeling energized during both the morning and night and alternatively, a “lethargic” group who felt lazy in the morning and at night. Unlike the owls and larks, these two new types didn’t display extreme differences in terms of sleeping and waking times – they fell mid-way on the spectrum between the Larks and Owls.

This research forces us to reconsider the restrictive two-type model. Instead, researchers argued that there are “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.” As a funny gesture, the authors of the study, instead of proposing avian names for the new types, preferred to try and crowd-source the new titles. Any ideas? People on Twitter have already proposed “Dodo” and “Pelican”.