More than 2,000 years ago, Hippocrates, the father of modern medicine, said, “The natural healing force within each of us is the greatest force in getting well.”
Many American physicians emphasize the importance of self-healing and immunity. Renowned doctor Andrew Weil wrote in his book “Spontaneous Healing” that the human body’s self-healing power is like a highly skilled physician inside our body.
One of the simplest yet often neglected ways to improve self-healing is by getting enough high-quality sleep. The benefits of sleep to the human body are not limited to restoring physical and mental strength; good sleep strengthens immunity and performs many other beneficial functions.
Furthermore, not everyone knows clearly why a person should sleep at the right hours at night but not during the day.
4 Self-Healing Hormones That Peak During Night Sleep
The top reason that one should sleep during the night is that we receive special gifts – four self-healing hormones from nights when we sleep at the right time.
Melatonin, growth hormone, prolactin, and endorphins are hormones important to our health. They are secreted and reach their peak during sleep.
Melatonin: Our Internal Clock
The pineal gland located in the center of the brain has been described as the “Seat of the Soul” by Renee Descartes.
A key function of the pineal gland is to receive the environmental light-dark status and convey this information by the production and secretion of the hormone melatonin.
During the day, daylight signals are transmitted from the retina to the suprachiasmatic nucleus, which sends signals to the pineal gland. Light prevents the release of melatonin; this function keeps us awake during the day.
At night, when there is little light outside, the pineal gland releases melatonin peaking between 2 a.m. and 4 a.m. and gradually falling after 4 am.
When we awake at sunrise and go to sleep at sunset, we follow the rhythm of night and day as if there were a clock in our bodies.
Melatonin can benefit the human body in many ways: sleep promotion, day/night rhythm control, mood regulation, immunomodulation, neuroprotection, bone growth, tumor suppression, antioxidant defense, inflammation reduction, and bacterial, viral, and parasitic infection prevention.
Melatonin exists in many edible plants (coffee bean, black pepper, barley, bean, cucumber, potato, rice, tomato, corn, almond), fruits (berry, grapes, apple, bitter melon), and herbs (wolfberry, fennel, fenugreek, agati, alfalfa, green cardamom).
Food supplements can also provide a source of melatonin.
Growth Hormone for Growth and Immunity
Sleep helps children to grow taller, mainly because of the role of growth hormone.
Many people are unaware that growth hormone can also boost immunity—increasing the number and function of lymphocytes, promoting the operation of natural killer (NK) cells, and increasing the body’s ability to fight viruses.
Growth hormone is mainly secreted at night, about an hour after falling asleep. Most (85 percent) of the daily growth hormone is produced at night, with a peak between 11 p.m. and 1 a.m.
Delayed sleep will delay growth hormone release and reduce the total amount of growth hormone secreted.
Growth hormone promotes the development of the body’s organs, bones, and muscles. It also promotes lipolysis, supplies energy to cells, and promotes protein synthesis.
This process is especially crucial for the repair of immunity lost during the daytime. The immune cells lost during the day are replenished at night through the function of growth hormone; this occurs more quickly during sleep than during waking hours.
When a person sleeps, the number and function of lymphocytes, white blood cells, red blood cells, and phagocytes are increased, enhancing the body’s ability to eliminate viruses.
Prolactin for Breastfeeding and Boosting Immunity
Prolactin is a hormone that is not only responsible for lactation but also beneficial to the immune system. It strengthens the killing function of natural killer (NK) cells, promotes the maturation of dendritic cells and B-cell activation, increases the phagocytosis of macrophages, increases IL-2 receptor expression, and inhibits T-cell apoptosis.
The peak secretion time of prolactin is at night during sleep.
Endorphins: Painkiller and Immune Booster
When a person is hurt or stressed, the body’s pituitary gland and hypothalamus secrete endorphins. Endorphins, which can bind to opioid receptors to relieve pain, are natural painkillers and create a sense of well-being.
Endorphins can boost immunity because most immune cells—including neutrophils, macrophages, NK cells, dendritic cells, and T and B lymphocytes—have endorphin receptors. Endorphins activate innate and acquired immune function and secrete interferon, perforin, granzyme-B, and antibodies.
The secretion of endorphins follows a pattern. After reaching its nadir at midnight, it starts to increase and reaches a peak at around 6 a.m. During the daytime, it slowly declines.
Data from adult male subjects (hollow points) and elderly (round solid points) showed the mean circadian variations in plasma beta-endorphin, ACTH, and cortisol levels. Each point represents the mean percent deviation from the 24-h mean.
Cleaning During Sleeping
So-called good hormones are secreted when you sleep, boosting self-healing processes while cleaning up harmful substances.
What are these harmful substances? Cortisols, substances transmitted between nerve cells, epinephrine, and norepinephrine, are all decreasing and generally higher during the day.
Persistent stress may cause damage to the body’s cardiovascular and immune systems. We can reduce their harmful effects on the body and immune system by clearing them.
Furthermore, human cells have a self-repairing ability called cell autophagy. Fasting initiates cell autophagy, which removes the waste produced by cellular activities during the day.
When we sleep, we are fasting, and autophagy is triggered automatically. Therefore, cells self-cleanse when we sleep.
Eating a large meal right before going to sleep reduces the effectiveness of autophagy.
When we go to sleep during the night, increased secretion of melatonin can promote autophagy.
The brain’s autophagy occurs when we are asleep. As most of our neurons are not renewed during our lives, autophagy during the night is essential for the brain to maintain its efficiency during the day.
In addition, the blood flow to the liver increases when we lie down and sleep. The liver is a metabolic factory and is closely related to immune function. When liver function is enhanced, it helps eliminate invading bacteria and viruses. The liver’s detoxification function improves during sleep.
Sleep can also clean up one’s “emotional garbage.” People are generally more stressed during the day. Unless self-restrained, most people accumulate negative emotions during the day. Emotions are a type of material substance. If not cleared in time, emotions can pile up.
A story helps illustrate the results of sleep deprivation and extreme stress. Wu Zixu was a Chinese military general and politician of the Wu kingdom in what is known as the Spring and Autumn period (722–481 BC). When he crossed Shaoguan, he was blocked by the river in front and pursued by the Chu soldiers in the back.
When Wu Zixu crossed Shaoguan, his hair turned white overnight. It is likely that the lack of sleep and constant high level of anxiety caused the damage to his body.
Sleep can calm us down, and stop our worries at least for a few hours, and then those negative emotions will not harm us.
In summary, there is no one size fits all solution for everyone when it comes to when to sleep and how long. However, following our internal clock, it is best to sleep at the golden time (11 pm to 6 am) during the evening when our internal clock tells us to go to bed.
Views expressed in this article are the opinions of the author and do not necessarily reflect the views of The Epoch Times. Epoch Health welcomes professional discussion and friendly debate. To submit an opinion piece, please follow these guidelines and submit through our form here.
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Dr. Yuhong Dong, a medical doctor who also holds a doctorate in infectious diseases in China, is the chief scientific officer and co-founder of a Swiss biotech company and former senior medical scientific expert for antiviral drug development at Novartis Pharma in Switzerland.
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