An article asks, Reaching the stars: is human hibernation really possible? It’s not very deep — and it seems to not understand that hibernation is a physiological state of reduced metabolism, rather than a kind of freezing — and it seems to shift the goalposts a couple of times. It also seems to think that therapeutic hypothermia is a practical way to fly to Mars.
A few years ago, SpaceWorks Enterprises delivered a report to NASA on how they could use this therapeutic hypothermia for long duration spaceflight within the Solar System.
Currently, a trip to Mars takes about 6-9 months. And during that time, the human passengers are going to be using up precious air, water and food. But in this torpor state, SpaceWorks estimates that the crew will a reduction in their metabolic rate of 50 to 70%. Less metabolism, less resources needed. Less cargo that needs to be sent to Mars.
Whoa. Therapeutic hypothermia is a technique to reduce cerebral metabolic demand when the cranial circulatory system has been compromised. As the article notes, it’s been used for as long as two weeks, with intermittent arousals. Would a healthy astronaut be willing to undergo this procedure? Doesn’t sound wise to me. And do I really want to go on a trip where the bean-counters have figured out that they can pack half as much oxygen for me by rendering me unconscious in an ice bath for half a year?
A 50% reduction in metabolism also isn’t going to get anyone to even the nearest star, sorry.
But even worse — therapeutic hypothermia isn’t trivial. Here’s a review of the medical consequences of therapeutic hypothermia.
Treated patients in this trial reached target temperature to 34°C quickly but adverse events included periorbital emphysema, epistaxis, perioral bleeding, and nasal discolorations.
Not too bad, right? Air around the eyeballs, nosebleeds, small hemorrhages around the mouth, and bruised noses. I suppose that’s manageable. But then there’s this:
Adverse events associated with endovascular cooling include pneumonia, cardiac arrhythmia, thrombocytopenia, and vascular dissection.
I’d definitely want a doctor attending my awakening. Unfortunately, the doctor might have experienced this:
Uncontrolled re-warming has been associated with rebound cerebral edema, elevations in intracranial pressure, and death.
I think I’ll pass. It’s not to say it doesn’t have benefits in specific medical situations, but I wouldn’t want to risk compromising a currently healthy body.
It’s also completely different from the idea of freezing someone solid, to virtually no metabolic activity, and then thawing them out and having them survive. There’s a kind of bait-and-switch at play in these kinds of articles: squirrels can hibernate all winter long, and hey, doctors have cooled people’s body temperature to 34°C, so why not just suggest the feasibility of sub-zero freezing? The problem is that these are entirely different problems and technologies, there is no continuum here, and you can’t make this kind of blithe extrapolation.
In the next few years, we’ll probably see this technology expanded to preserving organs for transplant, and eventually entire bodies, and maybe even humans. Then this science fiction idea might actually turn into reality. We’ll finally be able to sleep our way between the stars.
I don’t think so. And it wouldn’t be anything I’d call “sleep”, either.