Free running (biology)
Under freewheel (Engl. Freerun ) is understood in the Chronobiology the free expression of endogenous approximate rhythm without synchronization by a timer , such as light.
In the actogram on the right, a circadian activity is shown. During the first 5 days there is a synchronization through light. If the light timer fails to appear on day 6, the free run begins: The activity begins a little later each day. The free-running period (τ) in this example is longer than 24 hours, so the start times are shifted to the right on the 24-hour scale.
From day 19 onwards, the free running is “captured” again by light, that is, the endogenous rhythm is synchronized again. It can also be seen that from day 19, the light output takes place at a later time than in the first 5 days and that a synchronization still takes place.