At this time of the year, our bats have gone into a state of torpor as they hibernate so they can conserve energy during cold weather and when food is scarce. In torpor they drop their body temperature to as low as 5⁰C and their heart rate slows down, but their blood must be able to continue to flow and supply oxygen to the body.
Recent research has discovered how they do this. Experiments with blood cells of both bats and humans showed that the red blood cells became thicker, less elastic and more viscous as temperatures dropped from 37⁰C to 23⁰C. However, the blood cells of bats continued to thicken even as the temperatures dropped further to 10⁰C, whereas those of humans did not.
This change (torpor) slows down the speed with which the red blood cells move through the capillaries of the muscles and lungs, allowing the blood cells to become highly efficient at gas exchange and uptake of oxygen throughout the body.
If drugs could be found that induce human blood cells to slow down further with cooling as happens in bats, then slowing human metabolism down by cooling could help to prevent further organ damage in surgical procedures.
There is also the possibility of cooling humans down (i.e. inducing torpor) for efficient long-distance space travel so they use less food and other resources. Why anyone would want to be subjected to this experience to go and live on Mars or some other distant planet is beyond me, but some would call it ‘discovery’ or ‘progress’ I suppose.
Similarly, I do not see much advantage in prolonging human senescence by studying the ability of axolotls to renew their organs and body parts as I mentioned in my last column. Personally, I would rather we try to repair the damage we are inflicting here on planet Earth.
