Buying Time in Suspended Animation; June 2005; Scientific American Magazine; by Mark B. Roth and Todd Nystul; 8 Page(s)

Fantasy writers have long been captivated by the possibility of preserving human life in a reversible state of suspended animation. In fictional tales the technique enables characters to "sleep" through centuries of interstellar travel or terrestrial cataclysms, then awaken unaffected by the passing of time. These stories are great fun, but their premise seems biologically far-fetched. In reality, we humans do not appear capable of altering our rate of progression through life. We cannot pause the bustling activity of our cells any more than we can stop breathing for more than a few minutes without sustaining severe damage to vital organs.

Nature, however, abounds in organisms that can and do reversibly arrest their essential life processes, in some cases for several years at a time. Scientists describe these phenomena by a variety of terms--quiescence, torpor, hibernation, among others--but all represent different degrees of suspended animation, a dramatic reduction of both energy production (metabolism) and energy consumption (cellular activity). What is more, organisms in this state enjoy extraordinary resistance to environmental stresses, such as temperature extremes, oxygen deprivation and even physical injury.