Your Best Body at 40+ by Jeff Csatari

Your Best Body at 40+ by Jeff Csatari

Author:Jeff Csatari
Language: eng
Format: epub, azw3
ISBN: 9781605291611
Publisher: Potter/Ten Speed/Harmony/Rodale
Published: 2010-03-11T16:00:00+00:00


ASK THE EXPERTS

Q. What do you do to relieve stress?

I listen to chill-out music. I like the Buddha Bar CDs and the Chillout Lounge channel on 1Club.FM, a free Internet radio station.

—P. MURALI DORAISWAMY, MD Chief of the biological psychiatry division at Duke University

The Stages of Sleep

As you go through your busy day, a chemical messenger called adenosine builds up in your body. This neurotransmitter is created as your body burns through glucose to energize your actions. The more adenosine builds up in your brain, the sleepier you will feel. This is one reason people who exercise sleep better. They burn more glucose and therefore store up more adenosine. At the same time this stuff is making your brain fuzzy, another brain chemical, melatonin, is being secreted. Its release is cued by your internal circadian clock, which is sensitive to light and time of day. As the evening wanes and darkness falls, more melatonin floods your brain to power you down and make you yawn. When you fall asleep, you alternate between deep restorative sleep and more alert stages and dream sleep. Your unconscious journey through the night is made up of stages, reflecting the pattern of electrical waves in the sleeping mind. There are two basic states of the sleep cycle: rapid eye movement (REM) and non-rapid eye-movement (NREM) sleep, the latter consisting of stages 1 through 4. During an average night, you typically experience four or five complete cycles.

Stage 1 is very brief, lasting just 5 or 10 minutes. In this stage, your eyes move slowly under your eyelids, your body starts to slow down, but you are just drowsy.

In stage 2, light sleep, your eyes stop moving, your heart rate slows, and your body temperature decreases. But if your toddler cries out for a glass of water or your dog barks at a prowler, you’ll still spring out of bed easily to deal with the crisis.

Next comes the deep sleep of stages 3 and 4 when it’s very difficult to rouse you from slumber. This is when your brain gets its rest. In stage 4 your body secretes growth hormone to repair and restore your muscles. It is also thought to be the time that immune functions increase.

About an hour and a half into the sleep cycle, you drift into REM sleep. Breathing speeds up, heart rate increases, and blood pressure rises. This is when guys get erections and women experience their equivalent clitoral enlargement, and your brain is writing bizzare screenplays involving long-ago lovers, hula hoops, and fox terriers that play the ukulele. Dream sleep is essential to our brains for processing memories, emotions, and stress. Researchers believe dreaming allows crucial learning and skill building.

The experts say that hitting a snooze alarm over and over to wake up is not the best way to feel rested. “The restorative value of rest is diminished, especially when the increments are short,” says psychologist Edward Stepanski, PhD, who has studied sleep fragmentation at the Rush University Medical Center in Chicago.



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