As soon as it is said that spring is coming, people start to rave. Everyone wants to get out. Climbing, running, squatting, just enjoying. For children, the whole year is somehow spring. The spring fever that comes with growing up is different. In any case, it is not so much the play instinct that drives the big ones outside. They are not driven from the inside out, but from far out: The sun flips a switch on people. Even the prospect of a few sunny days in a row suddenly makes their hearts beat faster. When it comes to feelings, adults are much more susceptible than children, extremely sensitive to the sun. In any case, externally controlled.
Joachim Müller-Jung
Editor in the arts section, responsible for the section "Nature and Science".
- Follow I follow
Spring doesn't really hurt, though. With one exception: people who suffer from spring fatigue and constantly feel dull and sleepy cannot really enjoy the fresh colors in nature and the warmth after the long winter. Out of a hundred people, however, there are only a few. For them, spring is really not a pleasure. The others, the vast majority of people, on the other hand, don't really want to go to sleep when spring comes knocking. Because just as the spring-weary curse their bodies, so everyone else begins to love their bodies. And that's literally the case.
The body suddenly produces much more hormones, the "happiness hormone" serotonin, for example, in the brain. It then flows through the entire body with the blood. Often one still reads that the sudden heat in the spring drives the production of hormones. That's wrong. If it were, people near the equator with their cool nights and hot days would have to be flooded with happiness hormones every morning after getting up.
A switch in the genome
Presumably, the misunderstanding also comes from the fact that the warming of the earth actually does something with spring. Our spring has been starting earlier and earlier for decades. Every ten years, spring begins almost two days earlier on average. This is not calendar spring. It is based on the Earth's orbit around the Sun and always falls on March 20. The "phenological" spring, however, which pushes forward day by day with climate change, is not determined by planets or the sun. It can be fixed at the beginning of flowering, for example of apple trees. The flowers and trees feel the warmth and react to it when it comes earlier.
Human hormones, on the other hand, are much less sensitive to heat. We are already warm-blooded ourselves and therefore harder to impress from higher temperatures. The effect of sunlight, however, is practically laid in our cradle. As the days get brighter and the sun shines longer, our endocrine glands become active. This is no different with us than with animals. So the switch for spring fever has obviously been installed very early in the evolution of life. We carry it around with us in our genome, so to speak. However, it is only activated by sunlight when the body is mature enough to produce the corresponding hormones. And to produce in such quantities that people suddenly become crazy with happiness and longing. They suddenly start flirting as much as they can, walk lightly dressed through the streets and lie in the meadows, suddenly seeing everything through rose-colored glasses. The English call this quite aptly spring fever.
Hormone dominance in the head
Where exactly the spring fever switch is located is not quite sure. The pineal gland in the head, a small cone of nerve cells in the middle of the brain, certainly plays a very important role. It used to be the third eye. Earlier, that was in the great reptile epoch, when the dinosaurs still ruled the earth. In New Zealand there is still a small dinosaur that has a light-sensitive third eye at the site of the pineal gland: the tuatara, the bridge lizard. The sun not only flips the spring switch in your head, but also the winter switch.
In winter, when it is rather dark, another hormone is produced in the brain that makes us really sleepy: melatonin. However, the time of melatonin expires quickly as soon as spring comes. Then the hormone regime changes in the head. This brings us back to the people who suffer from spring: Although we do not yet know for sure, they seem to have problems coping with this change from melatonin to serotonin. Not all people are the same.