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IS IT TRUE THAT WE ALL HAVE A ‘SLEEP ANIMAL’?
Have you taken one of those online quizzes that assigns you an animal based on your sleeping style? According to some, there are four types of sleep animal: wolf, lion, bear and dolphin. But in 2022, Fitbit introduced sleep profiles that identified users as giraffes, bears, dolphins, hedgehogs, parrots or tortoises.
These animals don’t seem to relate to the sleeping habits of the people they’re assigned to – unless those ‘dolphin’ sleepers only allow half of their brains to sleep at any one time, as the mammals do in the wild. You won’t find any of those sleep animals in the scientific literature, though. Only two are generally accepted by the scientists: morning larks and night owls.
These refer to a person’s chronotype, which is their natural preference for sleeping and waking across a 24-hour period. Chronotypes are thought to exist on a spectrum that runs from morning types (larks) to evening types (owls). About 14 per cent of adults are thought to be larks while 21 per cent are owls, with the rest of us falling somewhere between the two.
Studies have shown your cognitive abilities and your energy levels have links to your chronotype, with morning types more energetic and able to perform better on tasks before midday and evening types feeling a gradual increase in energy and ability over the morning and afternoon, before peaking nearer the end of the day.
Understanding your body’s preference can help you plan your days around your natural sleep habits – if you have the ability to tweak the time you start work, for example, or your wake-up time isn’t decided by when your kids get up.
There are genetic factors at play, though. Scientists have identified key ‘clock’ genes that predispose a person’s chronotype toward ‘morningness’ or ‘eveningness’, or neither. But your chronotype is not fixed, like your eye colour. Large studies have shown that chronotypes change over a lifetime. As children we tend to be early ris
