American Heritage® Dictionary of the English Language, Fourth Edition
- adj. Relating to or exhibiting periodic physiological activity that occurs more than once every 24 hours.
- adj. Cyclical with a periodicity significantly shorter than 24 hours, that is, more frequent than circadian.
- ultra- + (circa)dian. (American Heritage® Dictionary of the English Language, Fourth Edition)
“In fact, I, along with my twenty-four year old son, experience what is known as ultradian rapid-cycling.”
“For longer naps, test multiples of 90 minutes, which is called an "ultradian" rhythm in some papers, though the proper term should be "infradian" since it's less than 24 hours.”
“I'm ultra-rapid-cycling (ultradian) bipolar I with comorbid post-traumatic stress.”
“This "ultradian rhythm," the researcher Peretz Lavie and others have found, governs our energy levels.”
“Other researchers have called this our "ultradian rhythm.”
“During the subsequent half hour, his subjects were significantly more likely to fall asleep than at other times, clear evidence of the ultradian rhythm and the cyclical nature of our alertness and fatigue throughout the day.”
“After learning about the ultradian rhythm a decade ago, I redesigned my workday, especially when I was writing books.”
“I continued to begin my writing day at seven A.M. But instead of simply staying there as long as possible, I wrote in three or four separate periods of exactly ninety minutes and framed them as ultradian ‘sprints.’”
“We call these “ultradian” cycles, which literally means “less than a day.””
“The Israeli sleep researcher Peretz Lavie found fascinating evidence for the ultradian rhythm in a series of experiments he conducted.”
These user-created lists contain the word ‘ultradian’.
but now they're not because I looked them up. In cases of polysemy or homography, *of course* it was the oddest meaning that stumped me. ;)
Looking for tweets for ultradian.