Some days ago we were at a friend’s house. After watching a very very good Indian movie (Awaara by Raj Kapoor) which has nothing to do though with the rest of what I’m writing, our Indian host brought up a very interesting subject. He was reading the book A Search In Secret India by Paul Brunton. The author of the book had travelled in India back in the 1930s to find spiritual masters and see if their legends were true. We read an excerpt from the book about a yogi (advanced practitioner of Yoga) who demonstrated to the author his ability to slow down his heart until it stopped(!). The rest of us, being modern Europeans had great difficutly in believing it. After all we’ve all learned at school that heart is a muscle which cannot be controlled by your brain right?
Modern medicine tells us that: “The heart will beat independently of any nervous or hormonal influences. This spontaneous rhythm of the heart (called intrinsic automaticity) can be altered by nervous impulses or by circulatory substances, like adrenaline. The muscle fibres of the heart are excitable cells like other muscle or nerve cells, but have a unique property. Each cell in the heart will spontaneously contract at a regular rate because the electrical properties of the cell membrane spontaneously alter with time and regularly “depolarise”. This means the reversal of the electrical gradient across the cell membrane that causes muscle contraction or passage of a nervous impulse. Mus cle fibres from different parts of the heart have different rates of spontaneous depolarisation; the cells from the ventricle are the slowest, and those from the atria are faster.” — Dr I Kestin
So, what do freezing frogs have anything to do with it? Well, our knowledgeable Indian friend, seeing the disbelief in our faces, continued by describing us a certain type of frog that can freeze completely and come back to life again! Probably the most well-known case of this phenomenon is the wood frog (Rana sylvatica) which can be found even north of the Arctic Circle! The frog’s body consists of 65% water, so when they find themselves in freezing temperatures, well, they freeze completely! Breathing, heart beat, and muscle movements all stop.
How can this be done? Meaning, how can this be done, without the frog’s cells dying due to lack of oxygen? Well, there’s a catch here. What happens is that the frogs choose to freeze themselves, all but the inside of their cells! Meaning they have an active part in the whole procedure. As the freezing procedure begins, the frogs build up high concentrations of sugars or sugar alcohols in their tissues. This acts as an anti-freeze for the inner part of their cells! Gradually after this procedure has started, breathing will stop, the heartbeats will stop and all brain activity will cease. These frogs can freeze down to -5°C (23°F) without a problem, but when temperature drops to -15°C (5°F) they die (I couldn’t find an explanation for this).
When spring time comes, thawing begins and within an hour or two the frogs are back alive and croacking! I’ve found a very informative page about these frogs. You’ll find there a thawing frog video as well! (Look at the left column of the page for the links).
So we’re at the last part of our discussion — suspended animation — which is the same as the frog’s state I’ve just described. Scientists have put mice into suspended animation by exposing them to hydrogen sulphide and revived them by briging them back to normal air. The explanation for this was that hydrogen sulphide all but shuts down the bodyΆs usual demand for the oxygen it needs to keep cells ticking over. The way I like to put it is that the cells are being “hypnotized” and no longer crave for oxygen.
This leads to a huge drop in the metabolic rate – for the mice case the metabolic rates dropped by about 90%! Their body temperature from 37°C fell to 15°C and the breathing rate from 150 breaths per minute went down to a couple of really shallow breaths a minute. The same technique can help humans as well in a broad range of cases. Just imagine the possibility of putting somebody in suspended animation until proper medical treatment arrives. This alone is enough as far as I am concerned.
(reference: New Scientist)
There’s a long way from the yogi’s performance to true suspended animation for humans and I am still skeptical about the first. My faith in science however still holds as strong as ever.
All I’ve written here show why I find talking to physicists interesting 🙂
ps. I’d like to thank Danny, Melanie and Claus for this conversation.