Each person is a world, they say, in terms of habits. We don’t all have the same sleeping habits. There are some people who are early risers by definition, while others feel the need to stay up late. Michael Breus, an American sleep doctor, has classified human beings into four groups, and identified them with an animal: bear, wolf, lion and dolphin.

These four groups, which Breus calls, in his book The power of when, ‘sleep chronotypes’, should serve to identify ourselves in them and consequently, make decisions that allow us to rest more and better.

The groups are based on the time we wake up and when we go to bed. “Your chronotype influences the hormone levels, in metabolic function and body temperature, among others “, says Breus, in statements collected by The Sun.


Bears have an energy cycle that rises and falls with the sun. They tend to get up at dawn and in the afternoon suffer a ‘slump’ that makes them feel very tired at the end of the day.

About 50% of the population is ‘bear’. These people should be careful with their caffeine consumption so as not to alter their rhythm. In fact, they don’t usually do it after eating. In addition, always getting up at the same time brings benefits in terms of the quality of their sleep.


Wolves, on the other hand, stay up late and sleep more during the day, making true efforts to get up every morning.

They usually have a increased energy at the end of the day and they perform better at night.

Approximately 15% of the population are ‘wolves’ and, unlike bears, consume more coffee because they need it to feel awake.

Going outside in the sunny hours is also beneficial to feel awake, as well as exercise.


The lion naturally wakes up early and prefers to go to bed early too, but this chronotype has a particularity: need a nap after eating in order to keep up.

It is also estimated that 15% of the population is ‘lion’. The siesta is recommended to have a duration of 20 minutes and as early as possible in the afternoon. One trick to getting one of these perfect naps is to have a cup of coffee right before that nap, because the caffeine will kick in at the right time.


Approximately 10% of the population belongs to the category of ‘dolphin’. Are those people who have very light sleep and they get up several times throughout the night.

They are usually connected at night, which makes it difficult for them to fall asleep. For these ‘dolphins’ it is recommended that they avoid screens before sleeping, as well as alcohol and caffeine from the afternoon, that they seek total darkness and silence and if they can, that take a hot bath.