The Myth of the Eight-Hour Sleep

A growing body of evidence, garnered from both science and history, is beginning to suggest that the eight-hour sleep cycle may not be most natural arrangement for humans after all.  One experiment conducted in the 1990s, for example, seemed to indicate that when completely left to their own devices, people would sleep for four hours, then wake for one or two hours before falling into a second four-hour sleep.

More recently, historians have uncovered a wealth of historical evidence that humans used to sleep in two distinct segments, including diaries, court records, medical books and literature.  The historically recent change to this pattern could be the root of a condition called sleep maintenance insomnia, where people wake during the night and have trouble getting back to sleep

According to BBC News:

“... [R]eferences to the first and second sleep started to disappear during the late 17th Century. This started among the urban upper classes in northern Europe and over the course of the next 200 years filtered down to the rest of Western society ... In 1667, Paris became the first city in the world to light its streets ... [B]y the end of the century, more than 50 of Europe's major towns and cities were lit at night.  Night became fashionable and spending hours lying in bed was considered a waste of time. “

Sources:

  BBC News February 22, 2012 

Study: Lack of exercise in people suffering from arthritis

December 11, 2011 — Last week, NPR featured a story about a recent Northwestern University study on osteoarthritis.

The study, which evaluated 1,000 participants living with osteoarthritis of the knee, found that 90 percent of those surveyed did not perform at least 10 minutes of moderate activity through the course of aweek.

According to researchers, by exercising, muscles more effectively support the weight of the body and take pressure off the joints.

Learn what exercises you can recommend to patients living with arthritis by checking out ACA's Healthy Living Patient Fact Sheet on rheumatoid arthritis.

Source: American Chiropractic Association,www.acatoday.org

How Exercise Fuels the Brain

By GRETCHEN REYNOLDS

Moving the body demands a lot from the brain. Exercise activates countless neurons, which generate, receive and interpret repeated, rapid-fire messages from the nervous system, coordinating muscle contractions, vision, balance, organ function and all of the complex interactions of bodily systems that allow you to take one step, then another.

This increase in brain activity naturally increases the brain’s need for nutrients, but until recently, scientists hadn’t fully understood how neurons fuel themselves during exercise. Now a series of animal studies from Japan suggest that the exercising brain has unique methods of keeping itself fueled. What’s more, the finely honed energy balance that occurs in the brain appears to have implications not only for how well the brain functions during exercise, but also for how well our thinking and memory work the rest of the time.

For many years, scientists had believed that the brain, which is a very hungry organ, subsisted only on glucose, or blood sugar, which it absorbed from the passing bloodstream. But about 10 years ago, some neuroscientists found that specialized cells in the brain, known as astrocytes, that act as support cells for neurons actually contained small stores of glycogen, or stored carbohydrates. And glycogen, as it turns out, is critical for the health of cells throughout the brain.