Dead or alive - 11-03-2010
Where a conversation can lead to.
The other evening some club members were discussing bones, in particular Peter Holman’s, and we got on to the subject of healing rates and blood supplies. This proved to be an inspiration for me to pen the article below which I hope will be of interest to you.
I know some of you will have read this information, in part at least, by reading previous issues of the club newsletter or emails I have sent.
DEAD OR ALIVE:
Almost all of you is alive and therefore has a blood supply. The exceptions being hair (apart from the root), the same for nails and lastly the enamel of your teeth. This is why the hair is a good recorder of whether you have for example been taking drugs. The growth part of the hair will contain the drug by virtue of it’s blood supply and as the hair emerges from the skin that part will die and thus it looses the conduit for the disposal of this incriminating evidence. So when Bradley Wiggins was pointing to his long hair he was saying ‘look you can see I’m not worried about you taking a sample of my hair.’ The subplot was something like (can you trust those with shorn hair).
No Blood supply no growth or renewal.
Our Arteries and Veins are the superhighway which transports all our needs to our cells and unwanted items for recycling or disposal.
An adult male typically has 5Litres of blood.
Hematocrit - some of you have heard this mentioned re the maximum level allowed in cycling under UCI ( Union Cyclist International) rules.
So when we hear that the max allowable level is 52% it means that the red blood cell volume as a percentage of the total blood volume must not exceed 52%. This was set at such a level that almost all riders would fall below that level. Typically an endurance athlete will have a higher blood volume but the same sort of number of red blood cells than the general population so their hematocrit is lower than these couch potatoes. Thus for an athlete it would be somewhere in the mid to low forties.
If a riders % is over 52 it’s a pretty sure sign they have been up to no good-see below- and a rider is prevented from riding for a certain number of days when they are retested. The rider passport which professionals need has a record of these levels.
EPO- Erythropoietin. We hear of this as an enhancer of endurance. EPO drugs were developed as a treatment for those suffering from a low blood cell count (red blood cells) due to side effects of cancer treatments or for other clinical reasons. The body naturally contains EPO which stimulates the bone marrow to make red blood cells to replace those dying - red blood cells live for about 100 to 120 days and are replaced automatically. They also suffer damage as they squeeze through the capillaries - the final leg of the arteries feeding muscles/cells etc. So I speculate that sports people just might need to replace red blood cells at a marginally faster rate than couch potatoes.
So sports cheats use EPO type products to boost their oxygen levels -red blood cells carry the oxygen- and thus rate of energy release (power) and coincidentally endurance.
Before manufactured EPO sports cheats blood doped; that is removing some of you blood and keeping the red blood cells in cold storage and injecting close to the date of the competition they wanted to do well in thus giving themselves a higher than normal red blood cell count= more oxygen.
Iron - The red blood cells carry iron around the body and are sometimes called ‘iron hungry.’
Unfortunately they will also absorb carbon monoxide even easier than oxygen so that’s why it’s so easy to dies from carbon monoxide poisoning.
Blood Pressure- The typically quoted figure is 120/80. That is when the heart is pumping the pressure of the blood can support a column of mercury 120 mm high and when not in the pump part of the cycle the pressure could support a column 80mm high-these pressures at the exit from the heart.
There is a school of thought around that suggests that with a healthy diet our blood pressure should not rise with age. This conclusion has been drawn by looking at the ape family where blood pressure seems not to rise with age - bear in mind here that the great apes live for some 30 years or so.
By the time the blood has got to the farthermost reaches of the capillaries the pressure is a mere mm or two. You might then wonder how it gets back to the heart. Well the heart doesn’t suck it back, rather the deep down muscles squeeze the veins in a flowing movement and so example the venous blood from the feet rises. To stop the blood falling back down the body due to gravity the veins contain non return valves. Thus the blood is lifted back to the heart whereupon it is sent to the lungs to discharge carbon dioxide and take up oxygen. During exercise the muscles of cycling -for instance -aid the flow of returning blood.
Breathing- Did you know that your rate of breathing is controlled by the carbon dioxide level in the blood. So as your CO2 level increases due to exercising at a higher level so your body prompts the muscles controlling breathing to operate quicker.
Oxygen Debt- This is typified when you have exercised very hard and you are still breathing heavily even when stopping or riding easy. Here you body is getting the CO2 level down to a normal level. The phase when oxygen debt builds up is during anaerobic (energy released without oxygen as the agent) but in doing so the CO2 level rises dramatically. Aerobic means when oxygen is being used as the agent for the release of energy.
CO2. This is a bye product of energy release.
Stretching before/after exercise - This subject was raised by Mick H in the café the other day. He said that he had read/heard that stretching before exercise was considered to be of no benefit but was after exercise.
I support him as I also heard this but a couple of years ago now. I asked the wife of a Dartford Wheeler- who incidentally was a prime mover in setting up Team Darenth - about the story as a qualified physiotherapist (MSC) and about to take up a university post. She confirmed that post exercise stretching was valuable but pre exercise stretching of dubious value. So by all means warm up by pedalling the bike and stretch after completing your warm down.
Pre exercise stretching could damage muscles/tendons. Tendons connect the muscle to the bone.
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