Altitude Training Mask for CO2 Tolerance

[psimian]

Does anyone have any experience using one of the various "altitude training masks" for training CO2 tolerance? I don't mean wearing one while actively exercising, which seems to be generally regarded as unnecessary if not outright counterproductive because it increases oxygen usage by the heart and diaphragm.

Most studies seem to agree that there is a positive correlation between aerobic endurance and tolerance of hypercapnia/hypoxia. Studies also seem to support the use of CO2 tables, though it is unclear if they work for the same reasons as aerobic conditioning.

I found a reference to using a training mask to help keep blood CO2 levels elevated while recovering from high intensity sprints, and it seems to based on the same principles as the CO2 tables:

Activity: Hill Runs at 85-95% of max PE (Perceived Exertion) with no mask

Recovery Period: Don the mask and perform 10 breaths at a cadence of 3 seconds of inhalation with 7 seconds of exhalation. Choose a low to moderate mask setting for the first couple of workouts. We advise sticking to 3k until you can perform all ten of your recovery breaths during each set of your workouts in a non-labored manner.
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Has anyone tried anything like this, or know of any studies that might be relevant?

I am also curious about doing sedantary training with a flow-restrictive mask and a fingertip O2 meter to slowly elevate blood CO2 levels while maintaining a steady heartrate. This would seem to accomplish the same effect as CO2 tables.

 

[J Campbell]

Is this mask different than simply putting a plastic bag over your head? Could this kill you if you wern't careful?

 

[psimian]

Well, it certainly costs more than a plastic bag... It's basically a respirator (like painters use) that has been modified to restrict the air flow. The effect is kind of like breathing through a straw. I suppose you could theoretically pass out if you had the flow set too low for long enough, but it would get horrifically uncomfortable long before you got to that point. I'd guess the risk is about on par with blacking out as result of holding your breath (on dry land, without hyperventilating first). It's possible, but takes serious mental effort.

 

[Nathan Vinski]

A cheaper option to the hill running exercise you've quoted... run the hill at 100% and only do 4 breaths recovery with 5s inhale, 12s exhale, all without the mask.. You'll still end up with crazy CO2 levels.

Its always the same issues with these masks.. as they don't actually simulate altitude and just restrict air flow and you are always left with the same options. perform "x" with the mask, or perform "x" at a much higher intensity.. for the same results.

 

[psimian]

Good point. I was trying to come up with some scenario in which the mask might be useful, but it doesn't really do anything that can't be accomplished by just changing your breathing pattern.