“It ain’t what you don’t know that hurts you; it’s what you know that ain’t so.”
– Will Rogers

This week’s issue of the British Medical Journal has a fun article analyzing seven popular medical myths that even some physicians believe.  The article was covered in the popular press including in this Yahoo News article and in this article in Newsweek.

The myths are:

• People should drink at least eight glasses of water a day
• We use only 10% of our brains
• Hair and fingernails continue to grow after death
• Shaving hair causes it to grow back faster, darker, or coarser
• Reading in dim light ruins your eyesight
• Eating turkey makes people especially drowsy
• Mobile phones create considerable electromagnetic interference in hospitals.

Take a look at the articles if you’re interested in the details.

(Thanks to Timo K. and Linda T. for sending me links to the articles.)

Tangential Miscellany:

Have a happy and healthy 2008!

… not dark and SAD.
 
This week I have two quick important points about mood disorders.
 
First, this Saturday is the winter solstice which is the first day of winter and the day of the year with the shortest daylight.  (It’s also my wedding anniversary.  One of you please remind me on Friday!)  Every year in late fall or early winter some people develop increased appetite, sadness, excessive sleepiness and social withdrawal.  These are some of the symptoms of seasonal affective disorder (SAD).  Though SAD is much more common in more northern latitudes where daylight hours are even shorter, it does occur in sunny Los Angeles too.  The Mayo Clinic website has a very informative page on SAD.  Check it out if you know someone who doesn’t do well this time of year.
 
Second, last week I wrote about insomnia, and linked to an article that suggested that awakening in the middle of the night for an hour or two may be normal.  Barnet M. emailed me with a very important caution.  Insomnia might not be normal.  It might be a symptom of anxiety or depression.  If you are waking up ruminating about anxiety-provoking things, or if you’ve had changes in your mood or appetite or energy level, please don’t ignore your insomnia.  Discuss it with your doctor.  (Thanks, Barnet!)
 
Tangential Miscellany:
 
My wife, Janet, and I wish all my readers who are celebrating a merry Christmas.  May we all enjoy peace, laughter and health in 2008.

Insomnia is a very common problem, and sometimes a very frustrating and persistent one.  But what if our expectations of an uninterrupted 7 or 8 hours of sleep is unrealistic?  What if a night of sleep for 4 hours, wakefulness for an hour or two, and then more sleep for 3 hours is how most of humanity slept before artificial lighting?

In a provocative article last year in Applied Neurology, Dr. Walter Brown reviews historical descriptions of pre-industrial sleep and suggests that sleeping in two nightly shifts separated by an hour or two of quiet wakefulness is completely normal.  I encourage you to read it.  He proposes that the advent of inexpensive artificial light allowed us to stay awake long after sundown and has led us to be so chronically sleep deprived that we usually sleep for 7 uninterrupted hours nightly.  This uninterrupted sleep pattern has now become the new norm.  When our natural pattern of sleeping in two shifts reasserts itself, we find it abnormal and distressing.  We are sure something is wrong, and a whole industry has sprung up to reinforce our anxiety and help us sleep the way we think we should.

Our expectations about our bodies go a long way toward shaping what symptoms we find distressing and what we ignore.  Many patients are quite alarmed about entirely normal symptoms and refuse to be reassured.  But patients alone are not to be blamed.  Many forces have pushed modern medicine to pathologize normal symptoms.  After all, pharmaceutical companies sell prescriptions, not reassurance.  Doctors feel motivated to make diagnoses, not exclude them.

Physicians need to find a way to reassure patients when their symptoms are normal.  We need to learn to say “there’s nothing wrong” in a way that is not dismissive but credible and comforting.  And we need to become comfortable ourselves with the idea that sometimes there is no diagnosis.

(Thanks to Linda T. for pointing me to the article.)

Tangential Miscellany:

I began writing my weekly medical news posts almost two years ago.  This is my one-hundredth post.  The feedback and encouragement from all of you has been very rewarding.  I hope to continue to inform and teach as long as you all keep reading.  Thanks.

I’ve written many times about the U.S. Preventive Services Task Force (USPSTF), the most unbiased and authoritative group that reviews the literature on preventive healthcare.

Their latest recommendation is not surprising; it’s just a good reminder.  This week’s Annals of Internal Medicine has a USPSTF recommendation statement reaffirming their previous strong recommendation for periodic screening for high blood pressure for all adults.

The reasons are simple and well established by decades of studies.  High blood pressure doesn’t feel like anything; that’s why measuring it is necessary.  High blood pressure increases the risk of stroke, heart attack and kidney disease, which are major causes of death and disability.  High blood pressure is very treatable with safe medications that dramatically reduce those risks.

So if your loved-one hasn’t seen her doctor in a couple of years because she feels fine, or if your coworker is blowing off his high blood pressure because it’s only “a little high”, get them to see their doctor.