Personalized sleep: how to adapt your routine based on your chronotype!

The human body is a wonder of nature, with interconnected and intelligently organized processes.

Have you ever noticed how some people seem to instantly fall asleep at night while others are still full of life? This is the result of our wonderful biological clock, centered in the hypothalamus, an essential part of the brain. Orchestrates the body’s preparation for sleep. After 8pm our body begins to cool down and the nervous system calms down, signaling the approach of sleep.

There are two fundamental systems in our body: the sympathetic system, which drives us to action and energy, and the parasympathetic system, which promotes calm and relaxation. They alternate driving depending on the time of day. This phenomenon is not exclusive to humans; animals also follow their biological clock for migration or hibernation.

As darkness approaches, our body begins the production of melatonin, a hormone vital to health. Without melatonin we would age much faster and be vulnerable to common diseases. During sleep, our brain is engaged in «cleaning» information: it removes unnecessary data and stores necessary ones. Additionally, sleep gives the brain a chance to «cool down», preventing overheating. When we feel like our brain is “boiling,” the solution can be simple: get a good night’s sleep.

A person spends about a third of his life sleeping. A huge amount of scientific research has been devoted to the study of sleep, but even today scientists do not have a clear answer to the question of why the body spends so much time, apparently in vain. Even an article published in 2019 in Science by scientists from Boston University and Harvard Medical School obviously does not provide all the answers, but at least it provides some clarity. It seems that one of the most important tasks of deep sleep, without which neither humans nor animals can live, is simply to remove extra information from our brain.

Ancient Greek thinkers, including Aristotle, one of the most important philosophers of the time, spent time reflecting on the role of sleep. The works of Aristotle, particularly his treatise On Sleep and Waking (Περὶ ὕπνου καὶ ἐγρηγόρσεως), laid the foundation for the understanding of sleep for many centuries, until the emergence of neuroscience as a distinct field. Aristotle considered sleep essential for rest, especially for the relaxation of the senses, which cannot remain constantly exposed to stimuli. Furthermore, he argued that sleep plays a crucial role in the renewal of nutrients and the growth process.

Chronotypurile

But why are some people active at night (the so-called “owls”)? The answer lies in individual characteristics.

Dr. Michael Breus, a clinical psychologist certified by the American Board of Sleep Medicine and a member of the American Academy of Sleep Medicine, details how we can leverage individual chronotypes to maximize performance and health. He identifies four main chronotypes: the dolphin, the bear, the lion and the wolf, noting that they can evolve throughout life. Furthermore, some experts argue that by adopting a consistent routine we can reset our internal biological clock.

1. the dolphin – The «Dolphin» chronotype comprises approximately 10% of the population. These individuals have fragile sleep patterns, often being awakened by minor sounds. Characterized by heightened anxiety, risk aversion and perfectionistic tendencies, «dolphins» often suffer from insomnia. Dr. Breus suggests resting between 11 p.m. and 6:30 a.m., schedule important activities after 4 p.m., and include exercise after 5 p.m. in their daily routine.
2. bears – The “Bear” chronotype represents approximately half of the population. They align with the sun’s natural cycle, being active throughout the day. They are characterized by caution and kindness and tend to be health conscious. Most «bears» feel like they don’t get enough sleep and have difficulty waking up in the morning. Their optimal period of activity extends during the afternoon. Dr. Breus suggests that «bears» go to bed around 11 p.m. and wake up around 9am, with peak activity and efficiency around 3pm, remaining high until 11pm. For sports, «bears» are advised to start no earlier than 18:00.
3. lions – The «Leo» chronotype constitutes between 15-20% of the population. These people tend to rise early, ready to protect and rule. Characterized by responsibility, balance and energy, «Leos» approach life with solid confidence and are inclined towards success, although they may feel tired after a time. Dr. Breus advises «lions» to rest before 10 pm. and wake up before 6am. For them, the best time to exercise is 5 pm, while the ideal time to carry out important tasks and achieve significant results is between 7 am and 11 am.