“Originally hibernation was considered a continuation of sleep, but physiologically it is very different because your metabolism is totally suspended, although it is still regulated,” says Vyazovskiy. “Torpor, this extreme metabolic challenge, seems to do something to the brain or body which necessitates sleep, which in turn provides some type of restoration.”
Suspended animation in deep-space flight has been a movie trope since the dawn of science fiction, and for just as long NASA has been working to make it real. John Bradford of SpaceWorks Enterprises has been contracted by NASA to develop just such a technology. Inspired by the unique physiologies of animal hibernators, he is working on overriding the body’s steady 37-degree-Celsius core temperature in a technique called targeted temperature management. Metabolism slows by about 7 percent for every degree of cooling. Though uncontrolled hypothermia can be fatal, a constant 32-degree body temperature still allows for normal nerve functions that are critical for breathing and heartbeats.
“Humans can’t hibernate, but we can mimic how animals hibernate,” he says. “Earlier in our evolutionary history we did hibernate, but now it’s turned off.”
Did I mention he’s an engineer? Am I the only one who gets worried when engineers are hired to do doctorish things? For one thing, in true hibernators, platelets and white blood cells are sequestered in lymph nodes away from the blood vessels during dormancy. This prevents the blood clots that can form with inactivity and avoids the inflammation that causes kidney damage upon rewarming. There will be a lot of research necessary before humans can safely hit the pause button on their metabolisms. Luckily, Bradford hasn’t been permitted any real live human subjects yet.
Then again, doctors have been pursuing this capability for years in the field of emergency medicine. When a severely injured patient arrives at a hospital, minutes count. A rapid cooling of the body saves tissues that are cut off from blood supply—a slower metabolism consumes less oxygen—so cooling patients for surgery is now a routine procedure. A low dose of narcotics prevents the patient from shivering to warm themselves up. In China, experiments with therapeutic hypothermia put patients into a deep chill for up to two weeks before successfully reviving them.
It really would be great if we could make it happen. The advantages of crew hibernation could mean the difference between a successful Mars colonization and an Earth-bound humanity. Mars is only six months’ journey from Earth, so life extension is not the primary issue at play, but hibernation pods would cut down the required habitat size and food needs. They could even provide solutions to some of spaceflight’s most long-standing health issues. Spinal fluid rising into the skull in low gravity causes pressure that diminishes most astronauts’ eyesight in flight, but the hibernation state should help to clear up that issue.