Why is it comfortable to sleep in rainy days?

Related research also pointed out that when rain enters the brain, the brain will unconsciously relax and produce alpha waves, which is very close to the state of the brain when the human body sleeps.

First, the rainy weather is depressed and the sympathetic nerve is not strong.

Sympathetic nerve is related to excitement. When the weather is clear, the oxygen content in the air is high, which can fully supplement the burning energy, make people's sympathetic nerves excited, and their activity intention is obviously positive. On rainy days, there is more water vapor in the air, and the average molecular weight decreases, which leads to the decrease of air pressure. In this way, the oxygen content in the air is reduced, the sympathetic nerve is in a low state, and it will be sleepy in rainy days.

Second, melatonin is also involved in trouble.

The human body will increase the secretion of melatonin in dim light, and its function is to make people sleepy; On the contrary, strong light will reduce its secretion. Rainy days, dark sky and insufficient light time will increase the secretion of melatonin, so it is not surprising that people are tired.

Third, it may be related to evolution.

Many human behaviors are related to early evolution. For example, human beings are particularly alert to the rustling in the grass, which stems from their natural fear of snakes; When men choose a spouse, white is beautiful, because women with white skin are younger, which also implies a symbol of high status.

Similarly, poor sleep in rainy days may also be related to evolution. In ancient times, humans generally lived in caves or thatched cottages and were very worried about wild animals when they slept at night. On rainy days, wild animals generally do not appear, and people will relax their vigilance and gain a short sense of security.

After tens of millions of years of evolution, people have followed this habit. Rainy days mean "safety" in their subconscious. People can finally let down their guard in this weather, let nervous nerves relax and dream a lazy and tired dream.