Just reading this article
And I note
“ Effects of chronic exposure to high altitude on other systems are summarized in Table 1.
Which at the bottom mentions decreased VO2 max and decreased aerobic exercise capacity. The table itself lists a bunch of references at the top if anyone wants to keep digging.
This is a really interesting thread, thanks guys. One question I would have is … is there any data (or would it even be possible to obtain data) that compares a rider who constantly lives and trains at altitude with one who constantly lives and trains at sea level. I confess I haven’t had time yet to read through all of the linked studies, but I haven’t seen it mentioned yet.
Obviously the rider who trains at altitude can produce greater power when they drop to sea level and vice versa, but is there a fundamental difference between what a rider would produce if they only ever rode at one or the other? That is one of the questions Zwift would need to wrestle with.
As I say, fascinating discussion, and one that I hadn’t considered before.
@Gerrie_Delport and @David_Cooper
Is your thinking that if an athlete spends enough time at altitude, they will produce the same power that they are capable of at sea level? They won’t. They can’t because the oxygen density is lower.
After several weeks at altitude, any adaptations that can help compensate for the lower atmospheric pressure have occurred. They are acclimatized. Any further changes are insignificant.
This is my big question and how this can be tested.
Let’s say someone lived there whole life at altitude will it be possible for them to train to produce the same power as someone that lived their whole life at sea level.
We can test this by separating identical twins at birth, that’s always the answer.
As someone else? The question does not make sense.
Take someone who lived their entire life at high altitude, test them at altitude. Then take them to sea level and test them there. They will be able to make more power at sea level.
That is not what I am questioning, we have all the data to understand what happen.
My question is living and training at altitude does that make a difference.
Most of our races are where we live, not may people travel to do a race.
I guess I really do not understand what you are questioning. If you live and train at altitude, you become acclimatized. At that point it is well understood - as shown in the charts above in this thread - how much power you are losing at altitude. Compensating for this loss of power would be the point of Altitude Compensation in Zwift.
For example, someone living and racing at 6000’ is able to produce only 92.7% of the power that the same person would produce if they were living and racing at sea level.
I’m with you, Bhaltair.
That’s precisely why I brought up this topic and why I want to have it addressed by Zwift in the software.
I’m not concerned with the temporary differences that happen in power when going from sea level to altitude, or when going from altitude to sea level. I’m talking about reduced power output long after acclimatization happens, which is what you’re pointing at as well.
I live at 5,800 feet here in Boulder. I’ve been here for years. My power is about 8% to 10% less here, based on my own data, than when I’m at sea level past the acclimatization period. And my coach, Tom Danielson, has hundreds of athletes and loads of corroborating data. He also sees about a 10% drop for his athletes that live at about 6,000 feet.
In fact, he knows the power reduction at altitude, long term, is so real that when we do team races against each other in zwift for RGT, he creates an “altitude division” with our own podium.
To make the virtual races more fun though, I’d rather have the software account for the power drop of athletes who race on a trainer at altitude so that our avatar in game gets an appropriate boost in power output to compensate for the altitude induced reduction of power. That way, instead of having a separate division for altitude riders who end up going slower in the game and finish behind the sea level riders, the altitude riders can stay with the sea level peloton.
There’s enough studies done to show proof of the long term, post acclimatization period, reduction of power output as a result of lower oxygen density that zwift could confidently adjust power output of altitude riders. I’m just not sure there is anyone on their team that cares enough about this yet to work on it, or maybe there is, but they don’t have the bandwidth.
I haven’t checked where zwift headquarters is, but I have a feeling that if their main office was at 6,000 feet and their own executive team were trying to compete at that altitude, they’d change the algorithms pretty quickly to create altitude compensated power output in the game world.
Thanks for joining in on the conversation. Maybe one day this will get added into the app so we can level the playing field 
I see this as mostly a philosophical question. Should Zwift compensate for riders geographical life choices (living at altitude) and if so what others should it consider compensating for? Excessive humidity in Bangalore? Arctic conditions in Alaska? Pollution in Beijing?
I think the only way Zwift can play this is straight. You produced X watts today, this is how fast you go.
What about for people who live at sea level, but in really tall high rise buildings? Can we accommodate them too?
Sometimes I don’t eat a good breakfast and as a result I produce less watts, can I get a credit for that too?
Hey zwift, could you monitor my sleep and give me extra watts to make up for when I don’t get enough rest?
C’mon guys at some point we gotta just race and not focus on how much we think we aren’t being treated fairly
Thanks, Ketzal. Yes, I know I can adjust my weight to account for the 8% drop in power I have from living at 6,000 feet, but I’d rather not do that because it’ll look like weight doping on the zwift power site.
I don’t know what you’re referring to with Alex Dowsett struggling with this issue. Do you have a link to an article about it? Has he been racing in some of the pro races on zwift recently and having trouble because he’s currently living at a high altitude?
he constantly brings it up on his YouTube channel to the point that it’s a running joke.
Awesome. Thank you. Will check out some of his videos. Thanks!
Glad to hear other people are talking about this, because parts of this thread are starting to make me look like I’m complaining and whining about not being treated fairly.
All I’m trying to do is address known physiological responses of the human body so that those of us who are limited by altitude can still have fun racing with riders at sea level.
At any rate, thanks for the link to Alex’s channel
Forest: why can’t you have fun racing now? Is there no one in Zwift with whom you can compete?
Maybe I’ll just buy some oxygen tanks.
But what if you can’t afford those things? Is it tough luck? Are you suggesting Zwift should only accommodate the exceptionalism of those that can afford to pay to mitigate their own shortcomings while it boldly steps in to resolve the ‘living at altitude’ problem that money can’t buy?
The absolute only thing Zwift can do is say, here’s the way it works. You input watts, we output speed*
*Of your digital avatar
I’m not digging at the OP here, just pointing out that if Zwift deals with any exceptionalism, then it must deal with all exceptionalisms. And taken as a thought experiment, it very quickly becomes ridiculous.
I can, and I do. It can just get frustrating sometimes if I get maxed out from lots of efforts at 4.0 w/kg to 6.0 w/kg for 15 or 20 min in an A or B race and I still get dropped from the front group, meaning, I lose a chance to finish in the top 5 or top 10.
It’s still fun, but not as fun as being in the front group and pushing for a top placed finish.
Thanks for the question.
Ultimately, this isn’t a huge deal, and it’s definitely a first world problem.
I brought it up because other cycling apps like Training Peaks and Today’s Plan have altitude adjusted power and thought it would be nice to have that in zwift.
Annnyway, time to get on the bike and train.