A Word On "Biological Rhythm"

 Biological rhythm is the periodic biological fluctuation in an organism that corresponds to, and is in response to, periodic environmental change. Examples of such change include cyclical variations in the relative position of Earth to the Sun and to the Moon and in the immediate effects of such variations—e.g., day alternating with night, high tide alternating with low tide.

The internal mechanism by which such a rhythmic phenomenon occurs and is maintained even in the absence of the apparent environmental stimulus is termed a biological clock. 

When an animal that functions according to such a clock is rapidly translocated to a geographic point where the environmental cycle is no longer synchronous with the animal’s cycle, the clock continues for a time to function synchronously with the original environmental cycle. 

Humans similarly transported over great distances often experience fatigue and lowered efficiency for several days, a phenomenon known as “jet lag,” or jet syndrome...<<<Read More>>>...