What are the real consequences of never maintaining a circadian rhythm? How is circadian rhythm important for health and function? Where did it arise in evolution?
$\begingroup$ A similar question biology.stackexchange.com/q/1113/238 $\endgroup$– Gabriel FairApr 4, 2012 at 12:05
$\begingroup$ Note that your body maintains a circadian rhythm whether you want it or not! You may perturb it (e.g. by not sleeping or flying in another time zone etc.), but the molecular basis of circadian rhythm is always there (although animal models where is not there anymore do exist). $\endgroup$– nicoApr 4, 2012 at 16:18
In theory, having a circadian rhythm should help anticipating daily environmental changes (light, temperature etc.) so that the metabolic performance is maximized.
In practice, mice chronically exposed to environmental light-dark cycles with a period length dramatically shorter or longer than that of their circadian clock are prone to become obese. Moreover, animals kept under short cycles die earlier than mice kept under normal or extended cycles. So, chronic circadian disturbance by a shortened light-dark cycle increases mortality (at least in mice). In humans, shift workers are likely the population that is more susceptible to circadian cycle derangements.
$\begingroup$ Note that this is probably tied to the fact that most, if not all, of the hormonal system in our body work in a pulsatile way, which is controlled by the circadian clock. $\endgroup$– nicoApr 6, 2012 at 6:28