Owls and larks: what determines our circadian rhythms?

In fact, there are only 20% of owls and 10% of larks in the world. The rest of the people live in a medium rhythm, adapting to the circumstances.

For some people, the peak of productivity comes at 8 a.m. while others like to sleep longer and are effective at work only in the evening. Someone needs 5-6 hours a day to get enough sleep, while others need to spend at least 7 hours in a warm comfortable bed to function during the day. Those lucky ones who need very little time to rest are only about 3% in the world.

What happens when we sleep?

During 7-8 hours of sleep, the average person goes through five 90-minute sleep cycles. During these cycles, our body, heart and brain restore their functionality. Then, during REM sleep, the brain allows itself to relax a little and engage in activities that are more creative – it processes abstract ideas and concepts, strengthens memory and plasticity, and triggers the process of neurogenesis.

Let us consider what the differences between an owl and a lark.

Our body’s internal clocks work based on biological and social factors, as well as exposure to daylight. Light stimulates the production of the hormone melatonin in the evening and stops in the morning. Our energy levels, stress response, hunger and body temperature depend on melatonin levels. Although some sleep habits are programmed from birth. Our actions can also affect what time we go to bed and when we wake up.

“Larks” often have more time for physical and other activities, as they wake up early and have the opportunity to prepare for the new day without haste. Thus, they are more likely than “owls” to feel happy, healthy and productive, while having lower levels of stress and depression. But the level of physical activity can to reduce the differences between “owls” and “larks” in basic indicators of well-being.

Some studies by German scientists have also found structural differences in the brains of “owls”. It turned out that those who like to sleep a little longer are prone to the presence of abnormalities, which associate with the development of depression. However, it is not very bad. Other research suggests those “owls” are smarter, more outgoing, more resilient, and more creative than “larks”.

Productivity decreases when people do not adhere to their optimal sleep schedule. There may be a mismatch between social routine and the time when it is easiest for a person to wake up. Thus, “owls” often suffer in cities where an early start to the working day is encouraged, and “larks” – where life is active in the evening and at night. “Larks” find it easier to adapt to their normal workday from 8 a.m. to 5 p.m., while “owls” often suffer from such a schedule, they can’t work at this time.

Thus, people working in shifts have difficulties with memory, processing speed, and cognitive abilities. Such people may take modafinil (such as Modalert or Waklert) to maintain productivity and focus.