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John Platero

I currently use a Hypoxico tent and sleep 8-10 hours a night in it. My blood was tested before i started to sleep in it and my hematocrit level was 42. After two months of sleeping at over 8000 ft. my hematocrit level was 49.6, a 17.6% improvement in my red blood cells. Don't know where you got the 17 hour fact from, but 17 hours a day is not necessary to increase red blood cells.

Joe Friel

Hi John--That's from the research as reported by Wilber in his altitude book. There are fast and slow responders. You are probably on the fast side. Good for you.


Joe, There is obviously some adverse effect from cycling at altitude.

However I think you should also counsel people to take things in perspective and not get overly concerned about this.

I worry that the fear of the effects of altitude will be greater than the actual effect of the altitude itself.

By definition folks will be at their most tired at the top of climbs where has, in theory, the greatest impact. The last thing people should be doing at this point is worrying about oxygen levels and the like. They should be digging in and pushing harder.

Fwiw I have found that for me being well trained pretty much zeros actual impact of altitude. I have ridden and raced up the highest mountains in Europe so up to 2800m. The power data for the rides shows no significant correlation with altitude. The impact of good/bad pacing/nutrition is hugely greater.


Martin, everyone responds to altitude differently and this is a reasonable concern for first time riders at altitude. The passes in CO are >3,000' where oxygen concentrations are ~70% what they are at sea-level. The mountain towns are at ~2500m so traveling to CO to do classic mountain rides is more stressful to the body than Europe where you'll typically sleeping at a lower elevation your body is accustomed too and allow you to recover/sleep well. I agree that pacing/nutrition is ultimately a larger impact on performance but the altitude is a concern. Pacing at altitude is slower because there's less oxygen (an climbs make you work harder - talk about double edged sword) and nutrition is more difficult because fluid needs may change. I need to drink more at 8000'-10,500'than at 5000'-8000' rides. Cheers


My understanding in 4 words is: sleeping high/ train low


In response to Martin I have just returned from the Alpes. I know that I struggle a bit at altitude from my experiences skiing. Light headed, headache, nausea, generally feeling a bit unwell. I hoped that I wouldn't struggle so much cycling as the climbs generally stop at the bottom of the ski lifts rather than further up the mountains. But I did struggle. I was blowing like a steam train very early in each climb with a high HR. I rode the lauteret, galibier, glandon, croix de fer, d'huez, sarenne, deux alpe.

The guy I rode with had no problems with altitude what so ever. At my normal elevation I am a much faster and stronger rider than my friend. We are both of similar age 42-44 with me being the better trained. I race TT's.

The effects of altitude are very individual and people riding high mountains (above 1500 meters) should be aware of the physical effects of just being at that altitude as well as how the altitude could effect your riding.

At a European sportive a club mate was removed from the ride (a 6 day event) by the organisers due to him having trouble riding at altitude.

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