Why do we wake up before the alarm clock goes off?

Why do we wake up before the alarm clock goes off?


With the arrival of spring the swifts return, flowers sprout in the parks and terraces on the sidewalks and many of us feel lighter in spirit. Life on Earth is cyclical. There is a famous meme in which two aliens joke about the (poor) intelligence of the human species for celebrating that our planet has completed another revolution around the sun, but the truth is that daily rhythms (circadian, from the Latin ‘circa’, around of, and ‘ten’, day) and annuals are very important in our biology.

Virtually all living beings on this planet have a molecular clock in each of their cells, from a simple bacteria to a very complex neuron. In cells there are specific proteins that are produced, activated and destroyed mutually, which causes a cyclical behavior that, wow, lasts approximately 24 hours.

Coincidence? No. This is a case of evolutionary pressure to adapt our activity, metabolism and behavior to the duration of our planet’s rotation around the sun, and which originated at the same time that life appeared on Earth.

To ensure that these molecular clocks are synchronized with the light-dark rhythm marked by the Earth’s rotation, animals use a complex system of hormones, which are produced in a small region of our brain called the hypothalamus and arrive through the bloodstream. to all organs.

One of these hormones is melatonin, which will surely be familiar to those of you who frequently take intercontinental trips. Melatonin is synthesized by our brain at night, and travelers with ‘jet lag’ – the imbalance that we feel in the body when having to adapt to a different time zone usually after a long-distance trip – take it to be able to sleep because it It makes our brain think that, whatever time it is, it is night and it is time to rest.

Clocks, routine and mental health

These molecular clocks are also responsible for us waking up five minutes before the alarm goes off in the morning because they allow us to anticipate what is going to happen in our routine and adapt our metabolism to expectations. Its functioning is essential to regulate reproduction, longevity, and even mental health.

In another sense, small alterations in the circadian cycle, such as staying up late on weekends or the annual time change – like the one that took place this Sunday – do not have any effect on our health, since in a few days the clock returns. to synchronize automatically.

But there are other situations in which the effects are more evident. People who work shifts, sometimes in the morning and sometimes at night, suffer serious alterations in their circadian cycle that have been linked to increased risks of heart and metabolic diseases, although it must also be taken into account that night jobs are not usually compatible with a healthy diet and exercising regularly. In laboratory mice, chronic disruption of molecular clocks even leads to reduced survival.

The opposite example is living beings adapted to life at the poles. During the long polar night, reindeer are able to maintain a 24-hour metabolic cycle thanks to their molecular clocks, even though they are not exposed to sunlight to synchronize them. Unfortunately, how Inuit or other Arctic people adapt to the lack of a light cycle, and how that may impact their health, has not been studied, although they are known to have high suicide rates.

Sync to heal?

With all this information, it is natural to understand that the therapeutic benefits of ‘luminotherapy’ are being explored, which consists of exposure to intense light that resembles sunlight. A recent study that reviewed 21 clinical trials concluded that light therapy has moderate beneficial effects in treating depressive symptoms, particularly those associated with seasonal depression, which usually occurs when winter arrives.

The benefits of light therapy in other diseases have yet to be determined. But surely a walk on the beach to exercise and resynchronize our circadian cycle feels good to us.



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