High Quality Sleep

Sleep is very valuable for human beings.

It can heal fatigues of your body and brain, enhance immunity, and get rid of stresses.

However, if the quality of sleep is low or the sleep is not enough, it will cause obesity, aging, weakening of the immune system and increasing of the cancer risk.

For a high-quality sleep, the secretion of melatonin, which you might call "sleep hormone," is required.

We usually start to secrete melatonin before sleep, and a large amount of melatonin is secreted during the sleep.

Melatonin is secreted from your pineal gland, but even if slight light enter your eyes, the secretion will be suppressed.

You should not use a PC or a smartphone before bedtime, and you should make your room totally dark while sleeping.

質の良い睡眠

睡眠は人にとってとても重要なものです。

体と脳の疲れを癒やし、免疫力を高め、ストレスを取り除くことができます。

しかし睡眠の質が悪かったり睡眠不足であると、肥満や老化、免疫力の低下や癌のリスクを増加させます。

質の良い睡眠には、メラトニン（睡眠ホルモン）の分泌が必要です。

私たちは大抵、眠る前からメラトニンの分泌をはじめ、睡眠中に大量に分泌します。

メラトニンは松果体から分泌されますが、わずかな光が目に入るだけで抑制されてしまいます。

睡眠前はPCやスマートフォンを使わないようにし、睡眠中は部屋を真っ暗にするべきのようです。

• High Quality Sleep
• This sentence is perfect! No correction needed!

• Sleep is very valuable for human beings.
• This sentence is perfect! No correction needed!

• It can heal fatigues of your body and brain, enhance immunity, and get rid of stresses.
• It can heal the fatigue of your body and brain, enhance your body's immunity, and get rid of stress.

• However, if the quality of sleep is low or the sleep is not enough, it will cause obesity, aging, weakening of the immune system and increasing of the cancer risk.
• However, if the quality of sleep is low or you do not have enough sleep, it may cause obesity, aging, weakening of the immune system and an increased risk of the cancer.

• For a high-quality sleep, the secretion of melatonin, which you might call "sleep hormone," is required.
• To be able to sleep well/ To attain a high quality sleep, the secretion of melatonin, which you might call "sleep hormone," is required.

• We usually start to secrete melatonin before sleep, and a large amount of melatonin is secreted during the sleep.
• We usually start to secrete melatonin before sleep, and a large amount of melatonin is secreted while we are sleeping.

• Melatonin is secreted from your pineal gland, but even if slight light enter your eyes, the secretion will be suppressed.
• Melatonin is secreted from your pineal gland, but the secretion will be suppressed even if it is just a slight amount of light that entered your eyes, .

  I rearranged your sentence. :)

• You should not use a PC or a smartphone before bedtime, and you should make your room totally dark while sleeping.
• You should not use a computer or a smartphone right before bedtime, and you should make your room totally dark while sleeping.

Sleep in definitely important, but I never knew we need the room to be totally dark in order to sleep well! That is a huge problem for me, because I have a phobia of darkness and I always sleep with a bedside lamp. ><

• However, if the quality of sleep is low or the sleep is not enough, it will cause obesity, aging, weakening of the immune system and increasing of the cancer risk.
• However, if the quality of sleep is low or you do not have enough sleep, it may cause obesity, premature aging, weakening of the immune system and an increased risk of cancer.

• For a high-quality sleep, the secretion of melatonin, which you might call "sleep hormone," is required.
• For a high-quality sleep, the secretion of melatonin, which you might call (or: which is also called) "sleep hormone," is required.

Interesting! I must admit that turning off your smartphone before bed can help a lot.