Drowsiness and lack of sleep is a common phenomenon among young people nowadays, but they often want to sleep even if they are not sleepy on cloudy days. Why? Scientists help you explain the answer~
Whether you want to sleep or not is one thing, whether you can sleep or not is one thing, and whether you can sleep well is another thing. On rainy days, the three can be perfectly combined.
Low pressure, dark light, sleep at ease
In cloudy and rainy days, the water molecular content in the air becomes more and the air density decreases, so the air pressure is lower in rainy days. Compared with sunny days, the oxygen content of rainy days is lower, the sympathetic nerve is easy to be in a low state, and it is easier for people to stay at home, especially in the quilt.
In addition to sympathetic nerves, melatonin also makes people more sleepy in rainy days. In the 1950s, melatonin was discovered, initially expected to improve pigmentation and whiten, but scientists finally realized that it could make people drowsy.
Melatonin is actually a hormone secreted by the pineal gland in the brain to convey the 'Night' signal to the body. During the day, light inhibits melatonin production, and at night, melatonin is secreted into the blood - unless exposed to bright or blue light, it inhibits melatonin release and keeps people awake. On rainy days, the sky is dim, just like at night. It's not surprising that the lack of light time increases the secretion of melatonin in the human body and makes people feel sleepy.
There is also a view that people sleep safely in rainy days is related to early evolution. In the cave age, primitive people would live in caves or thatched cottages, and they would always worry about wild animals when they went to bed at night. On rainy days, wild animals are usually hidden somewhere, and the probability of attack is greatly reduced. People will relax their vigilance, get a valuable sense of security, and have a good sleep. Later, even after tens of millions of years of evolution, this habit has been retained. Rainy days are equivalent to 'safety' in human subconsciousness.
The sound of rain is a kind of white noise
Besides air pressure and light, another important factor that cannot be ignored in rainy days is the sound of rain. Why do you sleep better when you listen to the rain? Zhao Sijia, a doctor of Neuroscience at University College London and author of the guide to the use of the brain, explains that when you sleep, your hearing will continue to work, and the rain is similar to white noise, which will create a masking effect, shielding a lot of sudden sounds that may make people feel during sleep, so as to improve the quality of sleep.
Just as white light is composed of all kinds of monochromatic light, the so-called white noise means that the proportion of various frequencies of sound is balanced, just like the frequency of white light. Yes, in addition to white noise, there are other colored noises - those with uneven power spectrum, such as pink, red, purple, gray, etc.
Like smell, which is often ignored but plays an important role, hearing works 24 hours a day, even when we are sleeping. In the unconscious state, if the consistency of the sound changes, the hearing will warn you: wake up quickly, there may be danger.
Then why can white noise help people sleep better? Zhao Sijia replied that this is because of the 'masking effect'. 'white noise creates a masking effect, blocking many small sound changes that you don't realize but still affect your sleep. '
On rainy days, the sound of rain is scattered. Usually, the cry of the neighbor's children is not so clear, and the sound of watching TV in the upstairs family is also far away. With white noise protection in rainy days, sleep becomes particularly enjoyable.
If you can't sleep all the time
If you always want to sleep and sleep soundly on rainy days, but you can't sleep on weekdays, it's better to imitate a rainy day.
One way is to make white noise artificially. This method is very easy to implement in today's increasingly popular intelligent terminals and mobile Internet. Zhao Sijia recommends a software called raincloud, which can be downloaded for free on IOS and Android platforms. The software provides 30 minutes of thunderstorm sound cycle.
There are many similar software, such as Muji to sleep app launched by Muji, which is quite simple in design. It provides a variety of white noises, such as rain, waves, streams, firewood, etc., and can freely set the playing time.
Su Rui, who occasionally suffered from insomnia, said in an interview that the personal test was effective. In addition, she also recommended another effective way to experience herself: "Muji to sleep is a software that I often use. In addition, she strongly recommended the ocean surf recorded by the famous natural recording master Dan Gibson, which lasts more than 90 minutes. It's a very nice pure natural wave sound, not a single cycle without music interference. Listening to it, it seems to be in the Cape described in the distant house, open and distant, and then fall asleep. '
Taking melatonin is also an assistant way that many people choose to help sleep. In 2011, the European Food Safety Agency conducted a review of the evidence for melatonin and concluded: 'melatonin can help reduce the time needed to fall asleep. '
But the effect of melatonin use, there are studies that are weak. In 2014, Patty & middot; duester published a systematic review of melatonin in healthy people with or without insomnia diagnosis. After summarizing 35 randomized and placebo-controlled studies, duester said that the results of melatonin in the treatment of insomnia are positive, but 'weak', and more large sample studies are needed. Philip middot Gelman, a sleep researcher at the University of Pennsylvania, once said: 'it's pretty clear that melatonin is a bad sleep drug. '