Do Cholesterol Levels Fluctuate Daily or Seasonally?

QUESTION: I'm being honest, I do everything I'm told. I stuck to the diet,
stopped smoking and exercised. Yet I can't make head or tails out of the
changes in my cholesterol levels. My doctor says the lab is a good one and
the tests are dependable. Can cholesterol levels change with the weather?
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ANSWER: I find myself smiling at the implications of this question, and
wonder at the content of the conversation that brought you to write to me.
It's debatable. Some experts say "yes" while others insist that it just
doesn't happen. Your cholesterol level is not a constant, year-round number
but tends to fluctuate daily and, yes, may even change seasonally.
Seasonal cholesterol level fluctuations do not occur in everyone, and
evidently there is no psychologic reason when they do, except perhaps for the
effects of stress.
A recent study showed that cholesterol levels taken between November and
January were 39 percent below those of the same people measured between
February and April. Others have recorded seasonal fluctuations; still others
note individual fluctuations but not any associated with seasons.
In yet another study, it was found that cholesterol levels might be
steady for long periods and then all of a sudden undergo astounding shifts.
It truly does not matter if cholesterol levels vary with the season
because anyone whose level is at the edge of risk should be watched carefully
by a physician. It is important to reduce your cholesterol level if you are
at risk of coronary heart disease and you probably are at risk if your
cholesterol levels are high.