Putting people into a state of suspended animation is a mainstay of science fiction, but a new study may have brought the idea closer to reality. By exposing mice to low concentrations of hydrogen sulfide gas in air, researchers slowed the animals' metabolic rate to a near standstill with no apparent ill effects.
Many animals undergo periods of extreme metabolic slowdown, or torpor, in which heart rate drops, breathing slows, and body temperature plunges. For some organisms, such as several species of hummingbirds, this drop in metabolic rate is a daily event. Other animals, such as bears, experience a seasonal slowdown for months while they hibernate.
Researchers have predicted numerous benefits of inducing torpor in people—for example, preventing further damage after a stroke or heart attack by slowing the body's often-harmful response, or putting a patient into a metabolically suspended state while he or she awaits a vital-organ transplant. However, scientists