Why do you want to sleep when it rains? It turns out the answer is not that simple

After a long period of hot weather, has it finally rained where you are?

On rainy days, listening to the sound of rain outside the window, I always seem to feel sleepy for no apparent reason. Why is that?

1. Low oxygen content in the air on rainy days

On rainy days, due to insufficient sunlight, plants cannot fully photosynthesize, resulting in low oxygen content in the air.

At the same time, when it rains, there is more water vapor in the air, which causes the air pressure to drop and the oxygen content to decrease. At this time, the brain will automatically make protective adjustments due to insufficient oxygen, and the excitability of the sympathetic nerves will decrease, thus causing drowsiness.

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2. It’s dark on rainy days, so melatonin is secreted more

On rainy days, the environment becomes dim because dark clouds block the sunlight, and the human body secretes more melatonin, a special substance, than usual.

Melatonin is a neurotransmitter that shortens the time it takes to fall asleep and promotes sleep. Melatonin is synthesized by the pineal gland in the human body, and its secretion has a distinct circadian rhythm, with secretion being inhibited during the day and active at night.

On rainy days, the sky is dark and the sunlight time is insufficient, so more melatonin will be secreted accordingly, so it is not surprising that people tend to feel sleepy.

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3. The sound of rain can help you sleep

From the perspective of human living environment, the sound of raindrops is "white noise" and can promote sleep. Noise is noisy and harsh, which hinders people's normal rest, while white noise is evenly distributed and more "pleasant" sound.

Raindrops drip on the eaves, windows or leaves. The sound repeats at the same decibel, melody and rhythm, which can easily hypnotize the human consciousness.

Experiments have shown that relatively soothing and regular white noise can make people feel calm and easier to fall asleep. Therefore, it is easy to fall asleep by listening to the sound of rain when it rains.

Source: Health Times, Sun Jianhua (Deputy Chief Physician of Psychiatry Department, Hebei Mental Health Center)

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