The performance of the human body varies throughout the hours of the day, resembling a biological clock that is deeply rooted in it, and more information is available about this clock to the extent that some doctors use it as an effective tool in the face of a number of diseases.

"There is a set of clocks in the body to improve its performance, and this is called the circadian system," says Claude Grunvier, a researcher at the National Institute of Health and Medical Research in France.

The existence of these clocks has been known for a long time, and in the past decades, research has shown that the activity of organs varies according to the different hours of the day;

The intestines, liver and heart tend to work harder at certain times, regardless of the rhythm of meals or physical activity.

Meanwhile, research in animals and then humans has shown that this rhythm was not just a response to the outside world like day and night, but rather it was recorded in our cells, starting with neurons in the brain.

The research has advanced enough that 3 researchers in this field won the Nobel Prize in Medicine in 2017, and has accelerated more in recent years in particular, to show that this clock is present in the cells of the entire body.

Grunvier notes that there are "clocks in the liver, heart, lung, kidney, and retina."

Biological clock and pain understanding

Day by day it turns out that these hours have a variety of effects, and a study led by Claude Grunvier, the results of which were published this summer in the journal Brain, indicates that the perception of pain varies in intensity over a 24-hour period.

In this work, 12 men were isolated from all external stimulation for about a day and a half and exposed every two hours to a heated probe, and their pain threshold varied systematically over time.

The researcher believes that this is a crucial step towards a better understanding of pain, noting that "one day we may be able to deal with it better by taking into account its fluctuations throughout the day."

The research falls within a larger school in this regard, as these rhythms are well known to some researchers and clinicians, enough to use them in the face of several diseases.

chronological treatment

This is known as 'chronotherapy' or 'daily medicine'.

In the opinion of its promoters, the applications will be diverse;

From oncology to cardiology to neuroscience.

In Alzheimer's disease or Parkinson's disease, for example, the circadian rhythm is already known.

But it's now known that this disorder often precedes symptoms, so it can be a preventable cause rather than an effect.

clock turbulence

However, in general, "we are still challenged to apply this knowledge about the role of circadian clocks in the medical world," researchers Ravi Allada and Joseph Bass warned last year in a scientific publication in The New England Journal of Medicine. .

Therefore, there is a lack of techniques that would allow the doctor to easily diagnose the disturbance in the circadian clock, and advise the patient in a directed way to change the rhythm of his life in order to avoid health problems.

There are other ways that may clash with reality, such as the idea that Claude Gronvier has ardently advocated for taking the time of day into account when giving chemotherapy to a cancer patient.

"Let's imagine that experience shows that the treatment should be between 10 pm and 8 am, this will lead to small organizational problems," says oncologist Pierre Santini.

"We are already living in a world - at least in France - where the health system is on the verge of collapse... You have to be very persuasive to fundamentally change a system where there is already enormous pressure," he says.

Therefore, it is not only necessary to demonstrate the effect, but also has a "significant impact on response to treatment and patient survival", concludes Santini.

Santini concludes that studies are currently insufficient in this area.