What time will you have a natural birth? When might you have a stroke? And why is the chance of an asthma outbreak between 2 am and 6 am 300 times greater?
Ian Sample Guardian, Haaretz
Before the silence of the night gives way to the sounds of the morning, when the bedroom is still dim and the alarm clock has not yet announced the beginning of a new day, a silent wake-up call passes through the body. As the reading gets stronger, the body begins to warm up, the brain begins to flutter in response to the renewed electrical activity, and the heart moves from the calm nightly rhythm to the beating of the day.
The transition from sleep to wakefulness is just one of the precisely coordinated changes that occur in our bodies throughout the day. Thanks to the biological clock, almost every point in the body and brain knows when it should work harder and when it can rest.
Chronobiology (the study of "body clocks") has already revealed some strange phenomena. If you want to shake hands firmly, do it after 6pm. If you want to bet on the time you will give birth (in a natural birth), focus on the hours 4 to 6 in the morning. However, not everything is light and casual. You are likely to die in the morning; Those suffering from degenerative rheumatism (osteoarthritis; osteoarthritis) will feel a worsening of their condition in the early evening hours; The likelihood of a short attack (asthma) is 300 times greater between the hours of 2 am and 6 am. In general, it seems that each disease has its own time to attack.
With the built-in biological clocks it is possible to know in advance what will be required of us in the coming hours, and to vigorously activate the organs we will need most of all. The clocks tell us when our mind is more alert, our stomach is ready to digest food, and when we can "turn ourselves off" - and go to sleep. "There is no point in exercising the body at full speed all the time if there is no need for it, and in fact, it is impossible," says Russell Foster, a neuromolecular researcher from Imperial College London. "Instead, you use what you need at the appropriate times."
20 hour day
It took scientists decades of research to find the location of the main "body clock". It seems that, at least among mammals, it shrinks to a block of 20 cells in total, in the part of the brain known as the SCN (suprachiasmatic nuclei) - part of the hypothalamus at the base of the brain. Among the cells, the scientists found series of genes that were activated, turned off and activated again, in 24 hours. This cycle has two effects: the transmission of electrical messages to the nervous system and the production of a secretion of hormones. These are scattered in the body like the bells of a clock.
The role of the SCN in time tracking was dramatically demonstrated in 1990, when Michael Manaker's team at the University of Oregon and Foster performed a special experiment. In the experiment, the researchers came across a golden hamster with a genetic defect, which caused endarlemosis in its biological clock. Instead of a 24-hour cycle, the hamster lives in a 20-hour cycle. The researchers took the hamster offspring that inherited the defective clock, and transplanted its SCN into hamsters with a normal biological clock. To their surprise, when the hamsters recovered, their biological clocks operated according to a 20-hour cycle. "This proved once and for all that the SCN is at the point where the master clock is," Foster said.
Since then, scientists have discovered that while the SCN sets the standard time for the body, each of the organs in our body uses the signals to set its own personal clock, similar to countries that set the time in their area by reference to Greenwich Mean Time. Many organs, for example the liver and kidneys, are five hours behind the main clock.
morning stroke
While scientists in the field of molecular biology individually examine the workings of the biological clock, other scientists study the dark side of the subject. Their discoveries have shed new light on diseases, and some believe that this may lead to a medical revolution. For example, due to the fact that our body is required to raise the blood pressure shortly before waking up, there is a greater risk of blood vessels bursting in the early morning hours, which may cause a heart attack. The risk of having a stroke also increases. The risk of having a stroke (cerebral infarction) is 49% greater in the hours between six in the morning and noon, compared to other hours of the day.
The dramatic increase in short attacks between 2 in the morning and 6 in the morning is apparently caused by the decrease in the level of cortisol, a hormone that is usually linked to stressful situations, but is also known as an anti-inflammatory chemical that prevents constriction of air passages. "Important" diseases also squint towards the clock. Many cancers progress dramatically at certain times, and appear dormant at other times.
Many who practice chronobiology believe that medicine missed something, because it did not consider the time factor. "Doctors and scientists learn that the body is in a constant state for 24 hours, and are not aware of the matter of cycles," said Michael Smolensky, an expert on the subject of "body clocks" from the University of Texas at Houston.
The result is that many of those practicing medicine, who are aware of the physiological changes associated with time, do not properly assess the consequences arising from this. A survey conducted by Smolensky among more than 300 American general practitioners found that 55% of them did not know when blood pressure rises. Only 26% knew what hours there is a high probability of short attacks, and less than a quarter of the respondents knew when a migraine usually starts.
Mouse clock
Many experts in the field are convinced that if doctors and drug manufacturers were to address changes in diseases depending on the hours, it would be possible to significantly improve treatments. Studies have proven that in certain diseases, taking medication at different times has a significant effect on the outcome of the treatment. Last year Ramon Hermida from the University of Vigo in Spain proved that the recommendation to pregnant women to use aspirin to prevent high blood pressure and pre-eclampsia is meaningless if they are not told at what time to take the medicine. His research proved that taking aspirin upon waking up or in the afternoon has no, or only little, benefit. On the other hand, taking aspirin before bed has a significant effect on lowering blood pressure. "Such a small thing, like swallowing an aspirin, makes a huge difference," said Smolensky.
The discovery that drugs work better at certain times has raised questions about how general chemistry tests are conducted. Before any drug is administered to humans, it is tested on animals, usually rodents. The laboratory mice we know are nocturnal animals. "This means that we tested chemicals, not just drugs, on animals whose physiology is 12 hours out of sync with that of humans," Foster said, "Does this mean we have to repeat all the toxicity tests? It is not a matter that has been completely ruled out."
Foster believes that the pharmaceutical industry will benefit from investigating the phenomenon of the effect of time on the action of drugs. Such a study will not only reveal what are the best times to take medicine, but also when not to take it. "Suppose you are testing a new anti-cancer drug that causes severe side effects and high mortality among animals. You decide you can't use the drug, and keep trying other drugs. However, if they had given you this medicine at a different time, for example, 12 hours later, the side effects might have decreased. This may be exactly the case where we give a drug that causes more harm than desired, and in addition we lose many other valuable drugs just because they cause severe side effects during the hours they were given," said Foster.
At the Paul Bruce Hospital near Paris, Francis Levy, a world-renowned expert in the field of chronotherapy, is testing whether anti-cancer drugs have a greater effect at different times of the day or night. So far, Levy has discovered that it is better to give certain drugs designed to treat pancreatic cancer at four in the morning. At this time it is easier to bear the side effects because the level of a certain enzyme that protects the healthy cells is at its peak. "This means that the patients can bear treatment at a higher dose," Levy said.
According to Smolensky, there are about 30 different diseases that can be treated more strongly with the help of precise and careful timing of the administration of the drugs, instead of the usual and familiar methods of "once, twice, or four times a day".
However, despite the recognition of the fact that time is an important element, some argue that the timing of taking all the medications for each patient may be excessive. "Sometimes the difference won't be that significant," said Peter Redfern, a pharmacologist at the University of Bath and author of the book "Chronotherapy." Redfern claims that there are other time-dependent components, for example, the time required to absorb the drug, which vary to such an extent that it is likely that all the profit resulting from determining the time of taking the drug will be lost. "It's not like it was ten years ago, when it would have been considered a crazy idea. Nowadays it is taken seriously. It is clear to us that this is not a hallucination", he concluded.
