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Secrets of the Siesta and High-Tech Mattresses

        Health | Sleep Journal

In my journey into the mysterious realm of slumber, I've been poking my groggy noggin into all the fascinating nooks and crannies of the world of sleep and dreams.

I've learned a lot, and have tried to pass my experiences on to you; but my notebook is crammed with a lot of interesting stuff I haven't found a way to share with you yet. So in this dispatch, I thought I'd gather up some of the best random bits and present, for your enjoyment, the following slumbo-potpourri.

Secrets of the Siesta

You probably think, as most folks do, that the custom of the siesta, common in Latin and Mediterranean countries, developed as a way to beat intense afternoon heat. In fact, it has nothing to do with climate at all; instead it's a response to the natural rhythms of the body.

We talked before about your body's circadian rhythms, which tell you when to sleep and when to wake. Research shows that these rhythms have two daily low points — times when your body's metabolism is at its slowest, your energy and vitality are at an ebb, and the urge to sleep becomes more powerful.

The first of these low points occurs between 1 and 4 o'clock in the afternoon — traditional siesta time. So the siesta is really not an attempt to escape the blistering sun, but a very sensible acknowledgment of the body's natural needs. (By the way, if you think it's those heavy lunches that make you drowsy in the afternoon, think again; research shows that sluggish feeling is caused by the the circadian cycle and not the digestive process).

During the second circadian low point, which comes between 1 and 4 a.m., our bodies dip even more deeply into torpor. Research shows that these are the hours when night-shift workers are most prone to accidents. It's also a time when the body is least able to fight off physical crisis, and some large scale studies on mortality show that these early morning hours, dubbed by poets as midnight of the soul, are the time when a high percentage of deaths occur.