Each year in Europe, the clocks are changed on two different occasions. On the last weekend in March, we change the clocks to summer time, meaning that we put them forward by an hour. At the end of October, we then go back to winter time, which is actually standard time.
Changing over to summer time was originally introduced in order to save energy. Since the sun shines for longer in the evening, the lights are not switched on as long. However, this original idea is a fallacy as more heating is needed in the morning during spring and autumn in return
Despite this, we continue to change the clocks and many people have to struggle with health problems shortly after. This is because of our body‘s internal clock. It is especially influenced by light and darkness. It has now been conclusively proven that a lack of light makes us feel low, makes it more difficult to stay awake and disturbs our sleep-wake rhythm. The impact of light deficiency includes a lack of serotonin – a messenger substance that lifts mood – in the brain, and an excess of the darkness hormone melatonin in the morning.
Our internal clocks and, as a result, our hormone production are disturbed by the clock change.
When the clocks go forward to summer time, we lose an hour of sleep and our melatonin levels cannot quickly readjust. This means that we are very tired in the morning and, by contrast, feel awake much longer in the evening, even though we have normally gone to bed by this time of night.
Conversely, we can sleep an hour longer in the winter time. Lots of people still wake up earlier though and so get tired earlier in the evening.
Each person‘s body adjusts differently to the new time but it can take between 4 and 14 days.
Daylight lamps are an appropriate means for compensating for a lack of light in the winter time. They simulate sunlight and compensate for the effects of lack of light as a result. More of this lacking serotonin is then produced and positively impacts our mood.
„Bright white light can be used in the morning to combat poor mood and sleep disorders – especially in the darker months. The white light early in the morning simulates the morning sun, which has an increased percentage of blue light, meaning that the light appears particularly bright. This light allows us to wake up better, improves our mood and activates our body, allowing us to get tired more quickly in the evening if we have been really active during the day.“
Dr. Michael Feld , sleep specialist
Source: Schlafen für Aufgeweckte, Dr. Michael Feld, 3. Auflage 2015;