Altitude Compensation?

Any thoughts on adding some sort of altitude compensation? Everyone knows you have less power at higher altitudes. I’m training at 7000 feet in New Mexico where there is roughly 20% less oxygen. Through my own experience, I’ve found I have roughly 10% less power at this altitude compared with sea level. Shouldn’t Zwift add some sort of compensation for this to even things out? 

Perhaps using location services to add a quotient to your power numbers that increases speed based on power numbers relative to altitude? I believe Trainingpeaks has recently come up with a formula for this. Anyone else agree? 

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+1 I’m 68 years old AND live/train at 9,700’ in Breckenridge, CO. so I’m doubly challenged in competitions!

The median power/workload reduction at 10,000’ is 15% vs sea level. 

The new TrainingPeaks WKO4 for Mac does have an “Elevation Corrected Power” calculation that falls within a couple percent of that 15% for my outdoor or non Zwift trainer rides in my case.

Unfortunately, we high altitude folks are in the minority, so this probably won’t get a high priority.

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Same Here- about 5000’ in Utah. I would like to see my power be compensated so we are all on the same playing field in races. 

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I’m at 7,900’ in Colorado and sometimes wonder about this while gasping for air after a hard effort.  I agree Eric it seems there are so many other variables at play for the programmers to consider that this would be a low priority.  Plus when I’m training I’d prefer my power output to be as accurate as possible without a correction factor.  

It would provide another opportunity for zdopers to cheat too…  maybe if there was the option for Zwift to ‘know your location’ it could resolve the cheating issue.

It would be cool to have the option to implement the correction factor during races then turn it off for training.  It would feel like racing a Ferrari after commuting in a Volvo.  

Good points Nate Nelson… you are right that what your actual power is at the moment is what counts. Adjusting for altitude doesnt help us at higher elevation because when we are on the road, our power is what it is- no adjustment.

I think I would most like to see it adjusted in a race or on a kom/sprint segment. I usually am in the top 5 in sprints any given day. That extra boost of power adjustment could be the difference between a green jersey and the bitter taste of 2nd place. But i guess i just have to remind myself that this is basically a glorified video game- i should just enjoy it for what it is.

The difference is that while we are seemingly all riding on the same course, we are not. Riding at 4 watts/kg at 7000 feet altitude is much harder than riding 4 watts/kg at sea level. I think there should be some sort of compensation to the speed of the rider on the course based on altitude, not compensation to the power output. 

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yeah you may be right. That seems to be the correct answer… dont change our power, change our speed. That way our power in zwift actually shows what we are producing at a given moment but we aren’t penalized by being at a higher elevation in the game. 

i wonder if anyone at zwift is actually paying attention to this thread or if we are just a bunch of high altitude suckers complaining to eachother :) 

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If zwift chose to support this, there’s good hard/quantitative data on which to base the correction.

http://www.joefrielsblog.com/2010/09/altitude-and-aerobic-performance.html

There are two aspects to the solution… collecting accurate location and/or altitude from users in their profile and performing the normalization on speed and/or power while a user rides.

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7200’

quite a few of us

I’m at 7,400, seems like it wouldn’t be that hard to use the ap to geolocate and confirm altitude.

I agree!  I’m in the Lake Tahoe area at 6,700’ - it would be nice to compare apples to apples against others.

Second, Third ah whatever 6200 feet here!

in denver at 5500. and going back and forth to north carolina at 800 feet. it appears to me that the difference in watts is approximately the same as the difference in the available oxygen which i believe is appoximately 15% less in denver than sea level. its a massive difference in zwift races.

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I created this table based on a few articles I read online:

 

I know this is a little hard to read due to the formatting, but you can copy and past the text into a spreadsheet if you’re interested…

Elevation 0 1,000 2,000 3000 4,000 5,000 6000 6,700 7,000 8,000 9000 10,000 11,000 12000 13,000 14,000

Available Aerobic Power
Acclimatized 99.90% 99.20% 98.30% 97.20% 95.90% 94.40% 92.70% 91.30% 90.70% 88.60% 86.30% 83.70% 80.90% 78.00% 74.80% 71.40%
Non-Acclimatized 100.00% 98.60% 97.00% 95.20% 93.20% 91.10% 88.90% 87.22% 86.50% 84.20% 84.20% 79.30% 77.00% 74.70% 72.50% 70.40%
Pernnett et al 99.90% 98.90% 97.80% 96.80% 95.60% 94.40% 93.10% 92.05% 91.60% 89.90% 88.10% 86.00% 83.70% 81.10% 78.20% 75.00%

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I’m afraid I don’t know the answer to your questions - sorry!

I’ll have to oil my chain and see how it goes!

Also, found a few links…

http://www.joefrielsblog.com/2010/09/altitude-and-aerobic-performance.html 

https://www.trainingpeaks.com/blog/the-effect-of-racing-at-altitude/ 

http://www.hunterallenpowerblog.com/2015/05/elevation-and-racing.html 

https://www.cyclingpowerlab.com/EffectsOfAltitude.aspx 

 

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