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  • 執筆者の写真Naoko Suga








Light Guides Sleep

In Spring one sleeps, unaware of dawn;

The phrase "In Spring one sleeps, unaware of dawn" means "spring sleep is so comfortable that you do not notice the morning has come, and you fall asleep. The origin of this phrase is the first part of a Chinese poem titled "Spring Dawn" by a Chinese poet named Meng Hao Ren. In any age, when spring comes and the bright, sunny weather is pleasant, we tend to oversleep when the morning comes.

Preparing to sleep in the morning?

As a matter of fact, morning light plays an important role in good sleep. This is because when we wake up in the morning and get a good dose of light, our bodies prepare to produce melatonin, which leads to sleepiness. Melatonin is a hormone secreted by the pineal gland, a small organ located deep within the cerebral hemispheres. Melatonin is biosynthesized from the essential amino acid L-tryptophan in the pineal gland via serotonin. Light signals entering through the eyes increase the concentration of melatonin in the pineal gland, but it takes time for melatonin to be produced. Therefore, if we are well lit in the morning, melatonin is high just as we are going to bed, thus leading to natural sleep. Incorporating morning light into the body's rhythm is the key to good sleep.

Use light in your sleep environment

Spring has sprung and the morning sun is pleasant, making this the best time of year to adjust to sleep. In Japan, April marks the start of a new fiscal year, and many people may be changing their lifestyles. In order to start a healthy lifestyle of "wake up strong and sleep soundly," let's take advantage of light. If melatonin can be biosynthesized by ourselves through light, let's take advantage of the pleasant spring weather and morning light to get a good sleep naturally. Let's start the new year with a good night's sleep and good energy.





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