Come on, Donna!  This CAN'T be the first time you have heard THAT term!  Have you been hitting the bottle of Granny's remedies again?  Or is creeping senility starting to gallop?  

LOL

Ya knowz I luvz ya, dear!  But I gotta get my digs in, when I can!  LOL!!

I am not sure where or when the term came into being, but I have been using it for a long time.  It is basically for us chronics.  

Chronics do not get the same number and intensity of hits all year long.  Most of us go through a tougher period, where we get MORE hits than "normal", and usually of a higher intensity than "normal", too.  The higher hit count and intensity period we call "high cycle".

Many of us follow along with episodics, in that spring and or fall, for many of us, is our "high cycle" period.  For many of us, we might also go through a "low cycle" period too, where we get less than our "normal" hits.

For me, my "normal" is 6 to 10 hits a day.  During "high cycle" I go up into the 14 to 20 range of hits per day.  A "low cycle" period for me is down in the 2 to 5 hits per day.  Unfortunately, my "low cycles" are few and far between!  Oh well, such is life!  LOL!

So, does that fully explain it for you, m'dear?

Chuck