Saturday, December 4, 2010

Oxygenation at high altitude!

How do you improve muscle, organ and brain oxygenation in sport and at rest? And what happens at high altitude - above 3000m

All summer long I worked on improving my breathing - especially in training and cycling competitions. The past couple of days on the glaciers gave the opportunity to try out "reduced breathing" in downhill skiing at high altitude. My expectations were that it would be much easier than during intense cycling or running at lower altitudes, but quite surprisingly the opposite turned out to be true. During the summer I'd cycled over the second highest mountain pass in Europe - right at home in Val d'Isère - the Col de l'Isèran - but it's only 2775m high. The skiing in Tignes goes up to 3500m and in Val to 3300m  It's when you get over 3000m that a difference in altitude can really be felt.

The point of controlling breathing through reducing the volume of air breathed for any given period is that very counter intuitively it actually leads to a much better oxygenation of the body. It hadn't occurred to me before writing this that perhaps the acclimatization to altitude that changes the blood to hold and deliver more oxygen is similar to the effect that simply reducing breathing has on the body. One thing clear is that both effects are progressive over a similar time scale. When climbing high, if you go slowly you adapt over hours and days to the thinner air - but also if you live at high altitude there is a slow and continued adaptation over weeks if not months or years. Perhaps some of the so called health benefits of living in high mountains are due to this greater oxygenation capacity of the body - despite the thinner air.

First thing that happens at -20°C or thereabouts is that your nose runs like a tap when you try to breathe through it. I found myself clearing it in true cyclist style by blocking one nostril with my glove and blowing out of the other - taking care not to get the proceeds all over my black ski jacket. I'm not sure how this will go down with clients, but we will see! It was quite hard to resist breathing though the mouth after each section of skiing, skating along the flat or even walking in ski boots and carrying the skis. There is an almost overwhelming urge to open your mouth and take a deep breathe at this altitude. Just a few moments of self-restraint though and the urge passes - giving the body a better opportunity to adapt more rapidly to both reduced breathing and the thinner air.

The first and most noticeable effect of reduced breathing is that you clearly stay warmer. Hands and feet don't get cold very easily and if they do they warm up again rapidly. It's pretty obvious to start with that an open mouth with a high volume of circulating air straight in and out of the lungs - exposing a massive internal surface area of around 160m sq. (the size of a singles tennis court), 80 times the surface area of our skin, is going to have some sort of negative impact on our body temperature. We do our best to cover up all of our skin when it gets that cold - but we expose our tennis court sized lung surfaces openly! Nasal breathing is known to cause turbulence in the back nasal passages that makes the air heat up before reaching the lungs. There is obviously still a heat exchange going on, but the air volume is dramatically reduced and the heat exchange is probably not happening so deeply near the core - though I'll need to look into that one. All I noticed in practice though is that I stayed warm when normally I'd be frozen and suffering.I know that the main reason though for staying warmer is that nasal breathing (more than just “reduced” breathing) causes blood vessels to dilate giving better circulation to hands and feet – and everywhere else.

I'd imagine also that another advantage of better oxygenation would be better alertness. Fast reactions and response times are needed when skiing off piste through trees and over hidden rocks and in variable snow conditions. Better oxygenation also favours less lactic acid accumulation which means less fatigue. I must admit that I didn't feel any muscular fatigue at all during those days - despite catching a bit of a bug (probably from prolific hand shaking with loads of sick people in the ski stations). The bug is almost gone after one day at home - just a slight headache remaining. I'm planning on making sure to nasal breathe all winter in the crowded cable cars and funiculars where people will be spreading winter bugs brought in from all over the world. It's known that nasal breathing eliminates about 98% of viruses and bacteria through entrapment in mucus, again helped by turbulence in the nasal passages. The trick as always is not just "breathing through the nose" but in accepting the resistance (air squeezing though the nasal passages) and slight "air hunger" this initially brings.

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