As bears have a long winter sleep, it’s easy to imagine they would be very stiff when waking up. After just eight hours’ sleep, we need to stretch to get our muscles working properly again. Were we to rest for five months – as hibernating grizzlies do – we’d waste away, says Stuart Blackman.
It takes only a few hours on a life-support machine for the human diaphragm, which powers our breathing, to weaken enough that it struggles to take over from the ventilator. Yet grizzly bears emerge from their dens pretty much as fit as they went in, albeit much lighter.
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- Do all animals sleep?
- What is hibernation, how does it work, and which animals do it?
How they maintain muscle mass is of great interest to medics treating muscle-wasting conditions, and several of the genes involved have been identified by studying hibernating bears.
One trick bears use is to recycle proteins that would otherwise be expelled in urine, rather than raid their muscles for raw material (which also means less getting up for the loo).
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