How does altitude affect power output?


Two Wheel Blogs has a simple and interesting analysis of how altitude affects Power output.

I live at 600 metres (2,000 feet) which appears to lead to just a 2% loss of power versus sea level. The highest I have ever cycled is a 2,802 metres (a little over 9,000 feet) on Col de la Bonette. I’ve also cycled Col de l’Iseran (2,770 metres) and Col du Galibier (2,645 metres). This altitude lead to roughly a 15% reduction in power versus sea level. Wow!

While these are three of the most beautiful and challenging climbs in France, there are many steeper climbs at lower altitude. But the thinner air clearly adds to the difficulty. See the article at Two Wheel Blogs for more details.

Below: I am sprinting the very last stretch versus an unsociable guy at 2,800 metres – at the Col de la Bonette – the highest road in France. My lungs are very close to exploding – but I beat him (ok he was a touch old).

Col de la Bonnette / Restefond

During our Tour of Wales this summer, we faced some incredibly steep stretches, but all of these were near sea-level. Gospel Pass, part of our Tour, is the highest paved road in Wales and it’s even below my house in altitude at 550 metres.

Below, Doreen “sprints” up a 20% stretch. Ah the extra power of oxygen-rich air!



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Happiest while cycling uphill.

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