chronobiologist

noun

1. A person who is involved in chronobiology.

   “This has been known for centuries, but it was only twenty years ago that the site of the biological clock (or, as chronobiologists usually call it, our circadian pacemaker) was identified.”

   “In the view of chronobiologists, individual biological rhythms are always regulated in a similar manner.”

   “A chronobiologist studies the cycles in human organisms and what is communicated by these cycles.[…]A medical chronobiologist studies life cycles in an effort to improve diagnostic and treatment procedures.”