“We are living in a biological darkness. Intervention is already happening today. It is happening in school and in hospitals: Picture intensive care units with bright lighting 24 hours a day. Look at workplaces, too. That is to say that the recent findings can’t actually be wrong, or can’t be any more wrong than the current scenario. But we are a distance away from being able to say what optimal lighting is, either in the morning, in the afternoon or at night.
It has been established that blue light can have a massive effect on the body's phases of waking and rest, and thus on the circadian rhythm, i.e. our organism’s scheduled and recurring processes. This is being looked at by chronobiologists and specialists in chronomedicine all over the world. The inception of these branches of science came in the 1960s, and in the so-called “Aschoff bunker experiments”.
In 1963, in the Upper Bavarian monastic community of Andechs, located between Lake Ammersee and Lake Starnberg, began a series of experiments still much cited today, studying humans’ internal clock. A team of researchers around the behavioural physiologist Jürgen Aschoff looked into the question of whether rhythmic processes, such as body temperature and the sleep-wake rhythm, were controlled by external influences or by an internal clock.
With this in mind, volunteer “guinea pigs” were sent into a bunker complex. They lived down there, excluded from the outside world – some of them for months. There was no daylight, no clocks, no radio, no television – i.e. nothing that could lead them to draw conclusions as to what time it was.
The researchers studied the behaviour of the volunteers and, for example, documented the times they ate and their sleeping and waking periods. The result: The body’s rhythmic processes are preserved in such a situation – only the sleeping and waking times of the subjects did not correspond to the 24-hour rhythm seen in the outside world. During the bunker experiment, the volunteers’ internal clock seemed to work on a 25-hour cycle.
“However, those bunker attempts were partly incorrect. The findings at the time pointed to a 25-hour internal clock – but this was down to the fact that it was assumed that none of the subjects experienced light. This was not true, though. The students (for they were indeed mostly students) were revising for their exams and found it a convenient time to do so – they still had a bedside lamp to read by. At the time of the experiment, it was assumed that this small light in the evening had no influence on the internal clock – this was incorrect, however. It in fact showed – although we didn’t work this out until recently – that this lighting in the evening, even though it was minor, has a negative influence on the internal clock.”