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Wellnessproducts > Light therapy

Shift work - is it ok to turn the night into day?

Nowadays, there is hardly anyone who lives a hundred percent according to the daylight cycle. To wake up exactly with the sunrise and to go to bed with sunset does not even seem possible to imagine in our work life as it is today. On the contrary, our 24/7 society seems to have very different demands, which do not come without physical consequences.
Fortunately, it does not mean that a person has to work 24 hours a day and seven days a week. However, many professionals are required to show a tremendous flexibility when it comes to working hours at certain times of the day or night. Yet, these challenges that are required by the working environment and the society are absolutely not an easy task for the body, which may react with negative after-effects.

Our so-called 24/7 society follows the need to keep certain shops or services continuously open, or to have hospital and cleaning staff working at night and to keep certain production processes non-stop running. This stands in complete contradiction with the circadian sleep-wake rhythm of human beings. It already starts with pupils and students who have to expose their bodies to an unnatural activity time. They need to get up in winter, for example, when it is still dark outside, and they often leave school or university when it is dark again. The effects of this kind of conflict with the inner clock of the body are more evident on shift workers. Sleep problems, increased blood pressure, depression and cardiovascular diseases are only some of the consequences from which shift workers suffer.

As studies on the sleep-wake rhythm show, practically every cell of the body is affected by these challenges. It is very interesting to highlight the precise interaction of daylight and the different functions of the body. In fact, we can find more than one 'internal clock' in the human body. Asides of the 'master clock' in the suprachiasmatic nucleus (SCN) that is located in the brain, there are numerous other "clocks" on the periphery of our body. For being physically and mentally healthy, all these clocks have to be synchronized.

The body perceives shift work like a never-ending jet lag

Similar to a jet lag, shift work surprises the body with a sudden desynchronization of the times. The internal clock no longer matches with the external day-night rhythm. The advantage of jet lag is, that the consequences disappear after a few days of adjusting to the new rhythm. But when it comes to shift work, it means a continuous jet lag. Shift workers have to continually subject their natural rhythm to an artificial rhythm that is required from them by day, evening or night shifts. Those few days per week that are free of work and follow a 'normal' rhythm are not enough to cure the jet lag. A regular sleep-wake rhythm is practically impossible.

Since scientists found out about the effect on health if the circadian rhythm of the individual is not in accordance with the signals coming from outside, the problems of shift work came more and more to the center of attention. Of course, such a serious intervention into the sleep-wake rhythm does not remain without consequences. When it comes to chronic desynchronization, there is more and more evidence of sleep problems, loss of appetite, mood changes and worsening of performance. In addition, shift workers may suffer from drug addiction as well, since they often take stimulants for working at night and tranquillizers or sleeping pills to sleep during the day. Based on investigations and their results, it is also believed that the chronic disorder of circadian rhythm may even lead to serious health consequences such as cancer, diabetes, metabolic syndrome or depression.

A study with mice revealed the fatal consequences of chronic desynchronization. Alec J. Davidson and his colleagues exposed mice to chronic jet lag in a series of experiments. The result showed that the chronic jet lag came with increased mortality. The effect was especially strong among the older mice, and advancing the rhythm was more dangerous than delaying it.

Does this mean that it is time for shift workers to adjust the requirements of the environment to those of their internal clock, instead of adjusting their bodies to unnatural times of sleep and work? What possible solutions might there be which are good for employees and for employers as well? In the end, it should also be in the interest of the employer, to avoid the increase of industrial accidents due to the disturbance of the circadian rhythm of employees.

A remedy requires more knowledge about the effect of light on the body

In order to find solutions, a detailed research of the interaction of the endogenous circadian clock with the external clock is of great importance. It is also necessary, to see the entire picture: which includes of course also the lighting in the workplace - especially at night. If the light is too bright, it promotes alertness and performance. However, it affects the sleep phase that follows the work. Since it has been proven that light can slow down the production of the 'sleep hormone' melatonin, researchers find it important to identify the far-reaching consequences that come with it when shift workers are exposed to bright light all night long. Certain diseases could also be explained with other important functions of melatonin, such as binding free radicals, which is important for the immune system.

Looking for a comprehensive picture when trying to understand the effects of light on the body, researchers find themselves facing interesting questions. How exactly does the body perceive daylight? Is there only one channel through the eyes or are there other ways? Where exactly are the light-sensitive receptors or sensors located in the body? And which of these have a good connection to our biological clock? Answers to all these questions would bring us closer to a solution for shift workers. For example, the important role of the color spectrum of light is a relatively new discovery. The body's response to a light exposure depends not only on the intensity of the light and the duration of exposure, as well as the time of day, but also on the spectral composition of the light that the eye captures.

What do we know so far about the effects of light? Virtually every type of life synchronizes its activity with the sun. This is also true for the human cells. Since the rotation of the earth around the sun determines our day/night cycle, it is also the one that gives the rhythm. Inside the human body, the internal clock follows this approximate 24-hour rhythm. Even without external signals - as it was proved by studies - the body is able to follow this rhythm. Therefore, one can assume that our internal clock is an endogenous system of the body. This system controls the hormones, neurotransmitters and many other mechanisms in accordance with the diurnal cycle. The influence of external signals is, however, very strong. With sunrise, the light-sensitive components of the body begin with hundreds of reactions that were dormant previously, during the night. For example, the number of monoamines (important neurotransmitters of the central nervous system) increases. At the same time, a synchronization of hormones takes place: The 'night-hormones' will pause and the 'day-hormones' will be active. Night or darkness on the other hand stimulates the production of the sleep hormone melatonin.

What benefit can be obtained of this knowledge?

A shift worker will never get used to this kind of wrong rhythm, not even after years of working against his natural 24-hour cycle. The body will always perceive it as work against his own internal clock - especially during the night shifts. A shift worker forces himself to completely change his rhythm, while the day-night sequence remains unchanged around him. There is a chance of influencing that different kind of circadian rhythm with artificial light of a certain intensity, color and duration of exposure. Night shift workers may sleep, for example, relatively peacefully during the day in two phases and in a dark place, and get awake at night with the help of light therapy.

Chrono therapy also offers other tools, including sleep restriction or administering vitamin B12 or melatonin. It would be helpful if the circadian rhythm could be left in harmony with the natural signals as much as possible. Shift workers should also possibly follow a rhythm of morning shift, evening shift and then night shift, and not vice versa. To avoid attacks of fatigue, it should be considered the possibility of taking short breaks from work, which would be of benefit for the concentration and performance as well. Quickly rotating shift systems would also be advantageous. This way, the shift workers would remain in a shift only for a few days. Not to forget that shift work is a difficult task for so-called morning types who out of habit get up very early. It is easier for so-called evening types to deal with night shifts.

Apart from the light, there are also other factors that clearly act on the circadian clock. These include social activities and meals. Therefore, regular sleep times, certain bedtime rituals and most of all a quiet and dark sleeping environment are also important. For example, it would be good not to have an alarm clock with luminous numbers. For people who are on their way home after a night shift, and who will sleep a few hours when coming home, it is good to wear orange tinted glasses that filter blue light. This way they could reduce the awakening effect of sunlight. Night shift workers should stick to their usual sleep hours even on their work free days and not wait until the night. Otherwise, they would have difficulty in switching back to the working nights. At least four hours before going to sleep, it is good not to drink any caffeine. The meals should be easily to digest. Fatty food should definitely be avoided - not just before bedtime, but also before a night shift. Generally, healthy food rich on proteins and carbohydrates is recommended. Coming home from a night shift, you might as well enjoy a light breakfast before going to sleep. Possible bedtime rituals could be meditations, relaxation exercises, reading, listening to soothing music or drinking slowly a good night tea or warm milk.

It would be ideal to coordinate the social activities with the sleep and awake times. People sharing the same household should not interfere with the sleep times of the shift worker, and enable him a sleep of reasonably good quality. It is very important to keep up social contacts and to participate in ordinary life as much as possible. Therefore, it would be the best to divide the recovery sleep after a night shift in two phases: one in the morning for about 4 hours and then 2-3 hours in the evening. Even sleeping pills with a short to medium effect may be taken.

Other useful tools to support the natural rhythm

Light therapy is a drug-free, natural remedy. For many years, artificial light that resembles daylight has been used to help people with sleep problems or winter depression. Over the years, the methods and tools have improved so now not only they are more comfortable, but also there are many different applications. The classic light therapy is based on light administration to the eye. Users are sitting at a certain distance in front of a light therapy lamp. The stronger the light intensity, the shorter the application may take or the greater the distance between the daylight lamp and the face may be.

Another possibility is applying light therapy through the ear. It was in 2008 that researchers at the University of Oulu discovered and explored how light information can also be conveyed through the ear canal to the brain. This led to the development of the very handy Valkee device that enables a mobile light therapy. You can apply it, for example, during breakfast preparation or on the way to work. The device uses much less energy than conventional daylight lamps and does not lead to possible eye irritation. The Valkee light therapy device is also used for treating sleep problems due to shift work.

However, the complex nature of our body does not allow us to forget that for a good solution it is often required a combination of several factors. Therefore, in the case of shift work, it is not sufficient to place hope on a sole tool or measure. In addition to the options that are mentioned above, a healthy lifestyle is also highly recommended. This includes preserving the body as much as possible from too many stimulants or drugs. Regular exercise, sports and staying outdoors are important, since the body needs components of sunlight (such as UV radiation, for example) in a certain dosage that usually are not given by artificial light.

This is a first helpful approach for shift workers, until science discovers more about the body and its interaction with environmental signals and influences. It seems that there is no way around nature. This could be considered quite a challenge for scientists. However, it is also clear that with the introduction of shift work, it was actually humankind who challenged nature. At least with the present situation, the message of our body seems to be clear: No, it is not ok to turn the night into day all of the sudden.
Published on 17.09. by Thomas Toernell