Disturbances of the biological rhythm can have consequences

Within WHO there is an organization called International Agency for Research Cancer ( IARC). 

This organization has produced a  monograph on night shift work and cancer.  We are doing night shift work during the time when people in general are usually sleeping. People often work night shifts  in health care, manufacturing, transport, retail and services sectors. In the monograph IARC says that night shift work probably can be carcinogenic  to human beings. This was based on limited evidence from human studies (about breast, prostate, colon and rectum cancers)  sufficient evidence of cancer in experimental animals and strong mechanistic evidence in experimental animal. (mechanistic evidence means that the physiological processes  behind the development of cancer  are known)

 

Among the mechanistic evidence you have research about the circadian clock. When the circadian rhythm is disturbed  the production of melatonin from the pineal gland is reduced which means less melatonin in the blood. One thing we know about melatonin is that it is a strong antioxidant which counteract the free radicals. Free radicals are produced in our cells when the energy in the body is produced but the free radicals are side effects which can hurt tissues and cells just as side effects of medical drugs can hurt. In the long run this side effects might be carcinogenic.

Other mechanistic evidence are effect of  sleep disturbances on the immune system, irregular proliferation of cells. (Needed to restore for example  damaged cells in the gastrointestinal canal – one can say that we haft night shift repairing work in the body  while sleeping.)

 

What happens to shift workers circadian rhythm is called social jet lag. If you fly over several time zones many disturbances happen with our body’s circadian clock. We can get sleep disturbances but many organs can be affected. Problems from the gastro intestinal canal are not uncommon.  The social jet lag started when we got constant access to good light regardless of the time of day. The advent of television and later other types of monitors have changed many people’s life and many are tied to the apparatus much of the time.   People seldom experience twilight and darkness which are natural stimulus for sleep. In addition, a lot of time is spent indoors and  time in the daylight can be a very small part of a day, perhaps only 10 percent.   Daylight a dark winterday in Sweden is perhaps 1000 LUX and a sunny day it can be significantly more up to 100 100 LUX. Insade the light is between 25-200 LUX. This is important  for the production of melatonin which during the day takes place in the mitochondria of our cells. The mitocondriia are the part of the cell where energy is produced and it is ingenious that the melatonin produced there during daytime and thus can neutralize the free radicals that are formed during the energy production.

As a matter of fact many of us live with a social jet lag, which can lead to many cases of illness. Some of these illnesses are serious. It is wise to try reducing these risk factors. The body has during thousands of years  developed mechanisms  to take care of our health and it is only recently we have got a lot of knowledge about it. A researcher Till Roenneberg said the following:  Imagine you put laundry in the washing machine and put on a program that will run for70 minutes. You don’t stop it after 10 minutes and take out the laundry ?!, But that’s exactly  how we treat our body when we go to the fridge and grab a sandwich late at night.  Then we break our body’s repair process. And there are many ways to destroy the natural body rhythm