Get the Right Amount of Sleep for Your Body

The Biological Clock and the Need for Sleep

Get the Right Amount of Sleep for Your Body

By Tracy Published at November 9, 2012 Views 6,922 Comments 1

My fascination with sleep includes our body clock or circadian rhythm. When it gets thrown off, it can upset our sleep and lives in many ways.

Before fire, what must it have been like to only have light between sunrise and sunset? What did people do after dark? Many mammals are nocturnal hunters; did man hide in caves for sleep and protection to avoid the dangers of the beasts he hunted during the daylight? Is this how the circadian rhythm was developed and evolved?

In the past, fire, candle light and even oil lamps provided very low level lighting, and although it changed the way life was lived, one’s body clock was not significantly affected and basically still tied to the “rhythm of nature.” Then, Edison introduced his incandescent bulb in 1879. He surely knew his accomplishment would be life changing, but he probably had no idea his invention would wreak havoc on the age-old, and important, body clock and ultimately disrupt the circadian rhythm of the masses.

One of my favorite sleep education resources, "The Promise of Sleep," was written by the “father of sleep medicine,” William C. Dement, M.D., Ph.D. and his co-author, Christopher Vaughan. Dement's book reports that Edison thought people got twice as much sleep as they needed; that the extra sleep made them “unhealthy and inefficient.” And, while Edison boasted that he slept only four hours a night, it's said he was an avid daytime napper, so he probably got a healthy eight hours of sleep in a 24-hour period.

As Dement teaches, “Over millions of years, our bodies have developed a remarkably precise biological clock that ticks like a metronome to regulate sleeping and waking. Since before the birth of our species, the daily rising and setting of the sun and the seasonal flux of light’s transit into darkness have shaped this molecular timepiece, until the clock itself has become a tiny mirror of the celestial clock.”

So, how much sleep does Dement suggest we need? Our circadian rhythm and sleep needs change throughout our life. Infants sleep about 15 hours per day, young children about 10 hours and by puberty, teens have a natural biological change in their circadian rhythm giving them alertness, an energy burst in the mid-evening hours. Just when adults are winding down in anticipation of sleep, teens are wired and alert. Teens need as much sleep as children, but the shift in their body clock begins the creation of bad sleep habits, night owl behavior, getting up early (and sleepy) for the start of a school day and the subsequent accumulation of sleep debt.

By middle age, about 50, our sleep needs begin decreasing. Most adults, with seven hours of continuous sleep each night can awaken feeling refreshed and without the need for day time naps. The elderly, age 65 and older, find that they become “larks,” going to sleep earlier and waking up earlier. Their need for sleep is about one to two hours less than during middle age. What an ironic turn of events that after retirement, when we no longer require the alarm clock and have time to sleep In, we no longer need to!

When we don’t understand our own body clock, it’s easy to get thrown off and it’s hard to get back on track. I think of the body clock as just that, a clock — precise and regimented. Our wakefulness and sleep should be strictly controlled as part of our routine daily living. We are not robots, so will have occasions to veer off schedule, but keeping to a strict bed time and wake up time keeps our body clock happy and us healthy.

If you want to learn, in detail, how and why sleep plays such a vital role in our overall health and well being, I highly recommend Dr. Dement's book.

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