Biological clocks

Biological clocks 

biological clocks do not measure time but allow living beings to live in harmony with the different rhythms of nature (Day and night, seasons, etc.).

Biological Rhythms

Nature is punctuated by alternations of all kinds: that of the day and night, that of the seasons (spring, summer, autumn, winter in temperate regions, but also rainy season and dry season in tropical regions), that of the Tides (tide High, low tide).

The activities of all living beings are also carried out by following cycles or rhythms, in accordance with those of nature. These are for example:

-Alternation in the same day of rest and activity, sleep and waking: diurnal animals rest or sleep at night and seek to eat during the day, while nocturnal animals do the opposite, starting to activate only at nightfall; 

– The alternation over a year between periods of activity and rest: in temperate regions, leaves and flowering from the end of winter, leaf fall and "sleep" during the whole bad season;

– Seasons-related behaviors such as hibernation and migration;

– Cycles of reproduction (flowering season, season of love, menstrual cycles in women and other primates);

– The rhythms according to which the body works in animals: heart rate, respiratory rhythm, body temperature curve throughout the day, production of certain hormones, etc.

There are many different rhythms, the duration of which is very variable: a few seconds (rhythm of production of certain hormones, heart rate), several years (flowering rate of some plants for example). Rhythms whose duration is close to that of a day are called circadian rhythms.

Biological rhythms are controlled by internal clocks

The rhythms of the activities of living beings occur in concordance with those of nature. Yet they are not triggered directly by the natural rhythms. Indeed, biologists have shown that certain rhythms are lost even in the absence of changes in the environment. For example, if you move an animal that hibernates to spend the winter in a warmer part of the world, it is still hibernating when the fall arrives.

In fact, not only do biological rhythms exist in the absence of changes in the environment, but they are passed down from generation to generation; So there are genes to order them. Thus, most living beings have internal biological clocks. They would have appeared very early in the history of Life on Earth: From the beginning of the primary age, more than 500 million years ago.

Nevertheless, the biological rhythms given by the internal clocks are also influenced by the external conditions, such as the length of day and night which varies according to the seasons in temperate regions. Biological clocks are in some way "remitted by the Hour" by the indications of the outside world, such as the onset of dawn or twilight.

Human biological Clocks

At the beginning of the years 1960, by enclosing volunteers in cellars or caves without any way of knowing or predicting what time it is or whether it is day or night outside, it has been shown that the human body continues to function according to determined rhythms. Thus, rhythms such as body temperature or hormone production are slowing down at a pace slightly longer than 24 hours (around 25 hours). The rhythm of the "Day" (waking period plus the period of sleep), it, grows considerably: it takes place over 30 hours.

The IMPORTANCE of biological rhythms

The adaptation of the organism to its environment, controlled in large part by biological clocks, plays an important role in the proper functioning of the body and good health. When the biological clocks are dissolved, it is the whole functioning of the body that is shifted, and the general health is affected.

The easiest way to understand this phenomenon is the time difference. When you travel between Paris and New York For example, you have to stagger your six-hour schedule. It follows a desynchronization between the rhythm of our clocks and the rhythms of the environment: it causes insomnia, fatigue and gastric disturbances.

The organism adapts fast enough to the new rhythms, but not all clocks are restarting on time at the same speed: It takes a few days for the bedtime and the sunrise to be synchronized again with the night and the day, but the other Changes in body temperature and hormone secretion, for example, take much longer to readjust.

The study of biological clocks makes it possible to better understand the mechanisms of occurrence of accidents, especially when driving at night or when working in shifted schedules. It also helps to influence the efficacy of certain medications: by giving a medicine at the right time, it increases its efficacy while reducing the risk of side effects. Finally, it plays an important role in the study of nutrition, since the different types of food are not used by the body in the same way according to the hours to which they are ingested.

Translated by Bayron Pascal.