Sleep # 2 Getting Enough Sleep Keeps you From Getting Coronary Artery Calcium

January 16, 2009

Sleep # 2  Getting Enough Sleep Keeps you From Getting Coronary Artery Calcium

Competency # 7 Sleep                Reference: King JAMA 2008;300(24):2859-2866 

 Getting a good night’s sleep is critical to keeping you from getting stressed out with your blood sugar.  We learned that last week.  Within just a few days of 5 hours of sleep, you become insulin resistant and start looking like a diabetic.  Bad news.   

Now, we have a study telling us all about the arteries in your heart and adequate sleep.  670 patients without known coronary artery disease agreed to participate.  495 finished the study.  It included men and women, Caucasian and African Americans.  Each one was tested for how much sleep they got by keeping a log (they turned out to be miserable at measuring sleep length accurately) and an “actigraph” which is a little wrist band that measures how often you move.  Turns out that “actigraphy” is a much more accurate measure of actually being asleep and is close to 90% with brain wave measurements of sleep duration.  It’s an easy and accurate measure of how much time you are asleep.  It doesn’t measure if you have sleep apnea or how deeply you are sleeping.   

Then, the volunteers measured their sleep and kept a voluntary log of their sleep duration for 6 nights in a row, on two occasions several years apart. What they found was pretty surprising.  There was a 33% INCREASED  risk of developing calcium in coronary arteries for every hour of sleep below 7 hours.  The mean sleep duration was only 6.1 hours, so everyone in the study was sleep deprived.  That risk reduction is the equivalent of having your blood pressure lowered by 16 mm Hg.  That is unbelievably huge.  

The study couldn’t measure sleep apnea, which is known to have a big effect on coronary artery disease.  They looked for it and excluded folks with it, but didn’t test everyone with a sleep study.  That is a weakness of this study.  But they found 4 hours to be higher risk than 5, and 5 was worse than 6, and 6 was worse than 7.  You get the drift? This is a whole new ball game with sleep.  We need to add sleep deprivation to our list of concerns for heart disease.  If you want a healthy heart, we all need to think of strategies to find the time to give ourselves adequate quality sleep. 

 WWW: What will work for me?  I’m thinking of strategies to make sure my sleep is better.  I have a bulldog that snores (Bulldogs by definition have ENT issues).  She has been moved to a crate out of the bedroom.  I don’t want my arteries to turn to concrete.   I thought I was being tough working extra hard and bouncing back from a late evening to an early morning job assignment.   Maybe that was true here and there, but as a habit?  I’m aiming for 8 hours in bed, lights out, every night.  How good is your aim?

This column written by Dr. John E Whitcomb, MD, Brookfield Longevity, Brookfield, WI (262-784-5300)