Sleep Cycle is Driven by Chemicals to Accomplish Many Functions

A woman sleeping. (iStockphoto)
A woman sleeping. (iStockphoto)

We have a 24-hour biological clock (circadian rhythm) that synchronizes a person’s sleep schedule with the changing amounts of light (day/night).

A tiny area of the brain, the suprachiasmatic nucleus (SCN), interprets light signals sent from the eyes through the optic nerves. The light triggers SCN to direct the brain’s pineal gland to release the hormone melatonin. There’s a big burst of melatonin into the body just as we go to sleep. Sleep researchers postulate that melatonin probably turns certain areas of the brain off and on as we transition into sleep mode.

Adenosine is another chemical thought to induce sleep. Adenosine levels increase during the day, making us sleepier the longer that we’re awake in an attempt to reach homeostasis (the body’s “steady state”). Once we fall asleep, adenosine levels drop, reducing the need for sleep and eventually prompting us to wake up.

Cortisol, known as a stress hormone, follows a different path. The blood levels of cortisol go down right before bedtime, allowing us to relax, but then increases throughout the night to encourage a fresh energetic start to the day.

While we are asleep, our body is working very hard to repair the internal damage done during the day.

Sleep helps heal tissues and restore them to its original form. Sleep is important for our immune system. Sleep deprivation impairs our ability to combat infection and stay healthy. It has been postulated that sleep effectively combat the accumulation of free radicals in the brain, by increasing the efficiency of our body’s antioxidant mechanisms.

Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons and can be formed when oxygen interacts with certain molecules. Free radicals have a capacity to cause cell damage (DNA), Cell damage can lead to cancer, aging, and a variety of diseases.
Antioxidants help us to prevent cell damage (DNA).

Although there are several enzyme systems within the body that scavenge free radicals, the micronutrient (vitamin) antioxidants are vitamin E, beta-carotene and vitamin C. The body cannot manufacture these micronutrients so they must be supplied in the diet (fruits and vegetables and pills).

Although it has not been proven, sleep helps with body growth by having some influence on the growth hormone. Studies investigating the effects of deprivation of active sleep have shown that deprivation early in life can result in behavioral problems, permanent sleep disruption and decreased brain mass.

Scientists have shown numerous ways in which sleep is related to memory. In one test, the average working memory span of the sleep-deprived group had dropped by 38 per cent in comparison to the control group.

Sleep researchers continue to work on the importance of sleep to keep us healthy and smart. So far the evidence shows that sleep does not harm us. In fact, without enough sleep we can look forward to lots of health problems in life. So, listen to your doctor and to your mother. Sleep well. Have sweet dreams. Wake up in the morning like a million dollar person and say, “Thanks, mom!”

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