Broccolidwarf said:
tobydawq said:
Broccolidwarf said:
Mayomaniac said:
The 2000m thing is an overblow myth, created by flatlanders.
A well documented myth:
https://www.higherpeak.com/altitudechart.html
A fine table. If only the relationship between athmospheric oxygen concentration and the ability of haemoglobin to bind oxygen was proportional, you might even have a point.
Sadly, it isn't (and this is based on science, rather than anecdotal ramblings from Sørensen and Riis), so the numbers in your tables are not particularly relevant.
https://breathe.ersjournals.com/content/11/3/194.figures-only
I'm amazed you and valv.piti are not hired by World Tour teams.
Since altitude has no relevance, they can all do away with the altitude training camps from now on.
You guys should give Ineos a call, this is not just a marginal gain!
Your annoying attitude really makes me want to just ignore you, but let me try:
I may not be hired by a WorldTour team, but I do have a Master's Degree in Sports Science, so I should know a little bit about this matter.
When you are at sea level, there is 20.9% oxygen in the air and under normal pressure this translates to a pressure of oxygen of approximately 100mmHg in the alveoles. This pressure, in turn, almost fully saturates the haemoglobin molecules in the blood.
When you ascend, the athmospheric pressure decreases. The oxygen percentage actually stays the same but due to a decrease in pressure, the oxygen pressure in the alveoles decreases correspondingly to the general decrease in pressure. Now, the table you sent in your post illustrates that if you, for example, are at an altitude of 4000 feet (I hate feet, but let's just play with that to talk about the numbers in your last post), the effective oxygen percentage (the percentage the given concentration of oxygen would correspond to at sea level) has decreased by 3 percentage points or 14.4%. This would translate to an oxygen pressure of approximately 85 mmHg.
However, this will obviously not affect your performance negatively by the same amount because the oxygen saturation in the blood does not decrease accordingly (here you have to look at my graph - imagine that you started at the right-most point of the graph, corresponding to 100 mmHg and move to the left until you reach 85 mmHg). Actually, the saturation may just have decreased by a single percentage point at an elevation of 4000 feet. And the oxygen saturation is of course the important parameter for an endurance athlete whose muscles need blood-carried oxygen to perform.
If we travel to 8000 feet we begin looking at the heights of the highest mountains in the Tour. Now the effective oxygen percentage will have decreased by 26.3% compared to sea level, which means that the oxygen pressure in the alveoles has been reduced to 73 mmHg. If you again look at my graph and see where this brings us, it shows that the saturation will now have worn off by maybe 5 percentage points. Still not really much, but enough to be felt - especially because these curves are obviously slightly different for individual riders.
I guess this brings me to a conclusion along the lines of Valv; you probably need to get to the really high mountains (Galibier, Iséran) before the altitude is really going to be felt. However, it is going to "be felt" by all in the sense that the power output decreases due to a slightly lowering of the blood content of oxygen; not through gasping for air.
But the really important part is that these tiny changes in oxygen saturation happen at slightly different altitudes for different riders.
And this all certainly means that you can't talk about altitude having effects as soon as the leading digit of the peak altitude begins by 2 instead of 1 (if we measure in metres of course).
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