Originally Posted by
smarkinson
1984 Francesco Moser set the hour record at Mexico City which is about 7,500 ft altitude. Less dense air at altitude makes for better aerodynamics.
It would be necessary for any rider to acclimatise to the effects of altitude. As you go up in altitude the air density (ie the air pressure) is less so there are simply less air molecules in a litre of air. As your lung capacity is largely fixed this means there will be less oxygen molecules in every breath you take. Up to 5,000 ft it's not really a problem but for every 1,000 ft above that you lose about 3% of your VO2 max. This article explains it and provides a lot of references:
https://www.nfpt.com/blog/understand...tude-challenge
It's generally known among pro cyclists that riding in high altitudes (+5,000ft) will lead to a decreased power output. If I recall correctly Phil Gaimon talks about the drop in power in this video of him winning the National hill climb championship:
https://www.youtube.com/watch?v=lQodP6n4KfQ
This is actually a math problem that can be solved.
Power output drops with altitude, even if your acclimitized. IIRC, at 10,000 feet, it's around a 8% drop even for acclimitized athletes. There are publsihed studies showing the effect for acclimitized and no acclimitized at increasding altitudes.
Wind resistence also decreases with altitude. So google the know data, and find the sweet spot altitude wise where the curves intersect.