Changing the clocks: Why do we put the clocks back and forward and which effects does it have on our bodies?
On the 28th of October it is time again: The clock will be put one hour back to local standard time. But why do we change the time and does this practice have effects on our inner clock and our wellbeing?
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Time change – back or forward?
We are all unsure sometimes if the clock is going to be put back or forward. A useful mnemonic is the image of garden chairs: In spring, we put our outdoor furniture in the garden to enjoy the first delicate sunrays of the year. When in autumn it gets too cold to spend time outside, we put them back in the cellar or in the shed. The time change follows the same rhythm: In spring, we put the clock one hour forward, while in autumn we put it one hour back. This is an easy way to always remember if it is time to put the clock back or forward.
Why do we change the time?
The idea of changing the time is not a recent one. Benjamin Franklin proposed already in 1783 to change the time in spring and in autumn to forgo one hour of artificial light.
The idea of establishing two different time regimes was being discussed again in the mid 70s amid the oil crisis, when limited resources led to a need to use less energy. Through the changing of the time the daylight could be used more efficiently. Consequently, in 1978 the time act was adopted. Two years later it came into force and the summer time was born.
However, the goal of saving energy was reached only in parts. According to the German federal office for environment, artificial light has certainly been used less, but more energy has been consumed for heating in the morning.
How does the changing of time impact us?
On the 28th of October we will put our clocks one hour back. Even though the shift from summer to standard time is more pleasant than the opposite one (we get one hour more sleep), it can have a negative impact on our mental health and general wellbeing. One reason for this is the lack of light resulting from the fact that it gets dark earlier in the day. When we get out of school or the office, often it is already dark outside and we have no chance to catch our daily dose of sunlight. When the retina of our body absorbs less light, higher amounts of the hormone melatonin are being produced, while the level of serotonin decreases. This leads to bad mood and can make us feel tired and drained.
Another reason why the changing of time can make us feel exhausted is that our inner clock suffers from a sort of jetlag. This happens particularly often in children, but can affect also adults and even animals.