Light& Sleep How lack of daylight affects our sleep
Light and darkness are the strongest clocks of our -inner clock-. In the morning, it is, among other things, the bright, high-energy, short-wave, blue morning light that gives the brain the impulse to wake up. The orange-red, long-wave light of dusk and later darkness, which leads to the release of the hormone melatonin, on the other hand, set our natural -sleep mode- in motion. This sensitive rhythm can be disturbed by various influences.
Lack of light leads to problems
Today, more than 80 % of all Germans work indoors. Here, despite subjectively sufficient brightness, illuminance levels of only about 600 lux prevail almost without exception. However, to become properly awake and fit in the morning, we need at least 2.500 lux. Especially in autumn and winter, we lack significant light intensities here. A lack of light leads to reduced production of the mood-boosting neurotransmitter serotonin and to an excess of melatonin in the morning. We take longer to get going and sleep disturbances, fatigue and low mood are more common than during sunny periods. Only 19 % of Germans say that they jump out of bed in top form in the morning. In contrast, 31% complain of significant start-up difficulties.
Smartphone use disrupts our healthy sleep
Another reason for this is that we watch too much TV in the evening or use smartphones and tablets before going to sleep.
It has long been proven that the use of digital media late at night can have a negative effect on sleep quality. The screens of these devices emit high-energy, blue-wave light that can interfere with the release of the sleep hormone melatonin in the evening and give the brain the impression of being in the -wrong- time zone. The body stays awake even when it is already bedtime.
With daylight lamps and light alarm clocks well through the day
Avoiding the smartphone in the evening, along with supplemental light therapy, can successfully restore an out-of-balance day-night rhythm. Daylight lamps with an illuminance of 10 are suitable for this purpose.000 lux at a distance of 30 to 50 cm. Then 30 minutes of light treatment during the day is sufficient, preferably immediately after waking up in the morning. The increased blue content of simulated daylight is perceived through the retina and stimulates activity in the brain. The luminous intensity of 10.000 lux and the color temperature in the blue range can lead to the production of the happiness hormone serotonin being boosted and the production of melatonin being hindered. We start the day full of energy and are correspondingly tired in the evening.
Warm light in the evening, on the other hand, hardly changes the production of melatonin at all. For a regulated day-night rhythm, a daylight lamp is therefore recommended, which can be switched to soft red light in addition to bluish-white light. This not only ensures well-being and a good start to the morning, but also promotes the regeneration phase in the evening.
For natural falling asleep and gentle waking up, light alarm clocks with sunlight simulation are also suitable, which can support the natural sleep rhythm. In this way, you can visualize your own sunrise and sunset. It’s easy to bring the sunset into your own four walls and benefit from a higher quality of sleep.
Sleep for the awake, Dr. med. Michael Feld, 3. Edition 2015
Beurer Sleep Atlas 2017. How Germany sleeps, Dr. med. Michael Feld, Prof. Dr. med. Peter Young, 1. Edition, 2017