Body

The article about the art of breathing
http://www.abc.net.au/science/k2/moments/s1392360.htm

Breathing & Oxygen

Listen to Karl talk about Breathing & Oxygen
(You will need Real Audio which you can download for free)

Breathing is not an optional activity – it is something that we have to do throughout our entire lives. Nearly 2,400 years ago, the great Greek thinker, Aristotle wrote his treatise, “On Breath”, in which he asked the very deep question, “How can we account for the maintenance of breath inherent in us?” Most of us think that we breathe because we are low in oxygen – but most of us are wrong, and this may explain why fit young people can fail to come up for air in a backyard pool – and die.

The main trigger to our breathing is not that we are low in oxygen – instead, it is that we are high in carbon dioxide. We are carbon-based creatures. Our foods have carbon molecules in them. We break these carbon molecules apart, extract the energy that holds these molecules together, and use that energy to run our daily metabolism. As part of the process, our cells marry single atoms of carbon to two atoms of oxygen to make carbon dioxide – which we breathe out of our mouths as a waste product. We absolutely have to get rid of this carbon dioxide, so carbon dioxide is the main trigger to keep us breathing. (By the way, low oxygen levels are also a reason to breathe – but a much weaker trigger than the high carbon dioxide levels in your blood.)

I had learnt this academically in Physiology classes, but I really understood this when I nearly killed myself on live television (Good Morning Australia, Channel 10, 1990). I was explaining why helium gives you a squeaky voice. I had prepared myself by hyperventilating helium gas for a minute in the ad break, before the camera swung onto me. Hyperventilating is breathing in and out quickly and deeply. As we rolled into the program, I began speaking in a squeaky voice, explaining why helium did this. After a minute or so, I finished the explanation, and the camera (and everybody’s attention) swung over to the hosts, Kerri Anne Kennerley and Tim Webster, on the Home Base. Without the camera’s glare, nobody was paying any attention at all to me.

I suddenly noticed that I was very slowly crumpling to the floor. I choreographed my slow-motion fall so that I didn’t make any noise (this was live television, after all, and I was a professional Weather Man with standards to uphold). Then, as I lay on the floor, I felt that my vision was fading. This was because the retina is a very oxygen-hungry organ, and my retina was being starved of oxygen. I gradually realised that I was passing out, and probably even dying. A very small part of my logical brain wondered why on Earth this should happen.

Suddenly, I remembered my first year Respiratory Physiology. I realised that I wasn’t breathing because in hyperventilating, I had blown off all the carbon dioxide out of my lungs and out of my bloodstream. No carbon dioxide meant no desire to breathe. I was passing out because I was very low in oxygen (I hadn’t breathed for two minutes) – and I wasn’t breathing because I was very low in carbon dioxide (because of hyperventilation).

I tried to breathe, but I couldn’t – it felt really awkward, like trying to take another breathe when you have just filled your lungs with air. As the world kept colour-shifting into more grey, I tried again, and suddenly I felt myself taking a huge gasp of air. Almost immediately, the world snapped into full sharp vivid colour again, and I realised that I was on the floor, panting loudly. One of the camera crew heard me, looked over and motioned me to be quiet by frowning and putting a very stern finger to his lips.

There have been some recent cases of fit young people dying in a backyard pool, while trying to hold their breath as long as possible. Perhaps some of them hyperventilated first, and blew off all their carbon dioxide – and along with it, the essential trigger needed for breathing. Then, as they lay on the floor of the pool, without the urge to breathe, they died without taking a single breath.

So, be very careful when you have a competition to hold your breath underwater, while skylarking in the backyard pool.