Suspended animation is the technical term for the slowing without termination of life processes by external means. Outside science fiction, the technique is hypothetical. Breathing, heartbeat, and other involuntary functions may still occur, but they can only be detected by artificial means. Extreme cold is used to precipitate the slowing of an individual's functions; use of this process had led to the developing science of cryonics.

Placing astronauts in suspended animation has been proposed as one way for an individual to reach the end of an interplanetary or interstellar journey, avoiding the necessity for a gigantic generation ship; occasionally the two concepts have been combined, with generations of "caretakers" supervising a large population of frozen passengers.

Suspended animation is also a common device in fiction used to transport individuals from one time period to another. Among the characters or works that utilize suspended animation are:

• Edward Bellamy's 1887 novel Looking Backward
• Robert Heinlein's 1957 novel The Door Into Summer
• Anne McCaffery's and Jody Lynn Nye's 1990 novel, The Death of Sleep
• Captain America, who survived the end of World War II and was revived by The Avengers in the 1960s
• Red Dwarf, which had one character surviving a radioactive crisis by spending three million years in stasis
• Star Trek: The Original Series episode "Space Seed" and Star Trek: The Next Generation episode "The Neutral Zone" and Star Trek: Voyager episode "The 37's", in which individuals from the 20th century are revived three and four centuries later, respectively
• Stargate Atlantis, in which most of the Wraith were hibernating in their ship until the caretaker was killed.
• Woody Allen's movie Sleeper
• 2001: A Space Odyssey, in which three scientists are placed in suspended animation for a spaceflight of a few years' duration, the ship being tended by two living astronauts
• Alien, its sequels and related works set in the Alien universe, in which characters call suspended animation "hypersleep".

See also For some “real life” starting points:

• Cryptobiosis
• Hibernation