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    How Long You Can Sleep On Your Arm Without Losing It...
    By Garth Sundem | February 16th 2009 05:00 AM | 12 comments | Print | E-mail | Track Comments
    About Garth

    Garth Sundem is a Science, Math and general Geek Culture writer, TED speaker, and author of books including Brain Trust: 93 Top Scientists Dish the...

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    Last night at two in the morning I woke to find someone had grafted a zombie arm to my left shoulder. I commanded it to move—no response. I jabbed it with my right hand—no response. I threw it against the wall—no response. Would this limb remain forever zombific? Medical literature is conflicted.

    The current guidelines for tourniquet use suggest a one-hour maximum for restricted blood flow to upper extremities and a two-hour maximum for lower extremities, but also admit that the onset and degree of tissue death (necrosis) varies according to patient age and physical condition. Past these thresholds, restricted blood flow can result in nerve damage. (The tingling you feel is your nerves’ way of expressing angst—a call to roll over before they get really pissed.)

    After four hours without blood flow, wet gangrene and the decomposition of tissue due to stagnant blood trapped in extremities can begin. Generally, your arm will not fall off due to gangrene (as might a finger or a toe); rather, if you allow the infection to progress (the timing of which varies widely), you will be forced to have the arm amputated rather than allowing the infection to become systemic. If not, you will die. Though, this is unlikely to happen to even the soundest sleepers.

    The short answer: It’s not good to restrict blood flow for more than about an hour and a half; it’s very, very bad to restrict flow for more than four hours.

    I expect comments thanking me for the following illustrative image.



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    Comments

    Gerhard Adam
    Was that photo the result of throwing your arm against the wall, or did you have a really intense nap?
    Mundus vult decipi
    Garth Sundem
    Actually, the photo's a foot—the result of sleeping a full night with my legs crossed.

    Garth Sundem, TED speaker, Wipeout loser and author of Brain Trust

    Gerhard Adam
    Yeah ... but was it a good night's sleep?
    Mundus vult decipi
    Garth Sundem
    The best. I think it was worth it. After all, today's prosthetics are better than real feet anyway.

    Garth Sundem, TED speaker, Wipeout loser and author of Brain Trust

    Gerhard Adam
    With a good recliner, you don't need them anyway ... (remote and you're good to go)
    Mundus vult decipi
    Garth Sundem
    You forgot beer. For shame!

    Garth Sundem, TED speaker, Wipeout loser and author of Brain Trust

    Hank
    Maybe he is a whiskey man?

    This circulation issue might explain why we move so much while sleeping, about every 15 minutes.    If we sleep 8 hours, that means we moved 32 times.   At 190# that means I moved about 3 tons during the night.   No wonder I am so tired when I wake up!
    Gerhard Adam
    Great point Hank.  In the interest of efficiency, I'm now going to consider my sleep time, my work-out as well.  Thanks
    Mundus vult decipi
    Garth Sundem
    Ha! True jenius!

    Garth Sundem, TED speaker, Wipeout loser and author of Brain Trust

    That....
    is....
    absolutly...
    disgusting!

    wow thanks for posting... I woke up from a 2 hour nap because I needed to piss like a race horse, and totally had a zombie arm... couldnt even unbutton my pants... awkwardly accomplished it somehow with only one hand. how do I know I have gangrene... i mean if I was sleeping and i dont know for how long and my arms partly dead... when will it become evident?

    Actually, tourniquets are coming back into wider use now. There have been studies, and it has been found that a tourniquet may be applied for up to 6 hours without major tissue damage. You really should not have a problem with sleeping on your arm for any amount of time. I have found that if I sleep on my arm, I think that I wake up pretty quickly, as the ability to move my fingers comes back in 10-20 seconds, and full feeling is restored in about a minute or less.