Gas masks and respirators are made to filter out dangerous airborne impurities from mid-air and provide an individual with a climate supply.
Gas cover up training has been falsely sold to sportsmen as an 'hypoxic training help', even although the structure of air filtered through the face mask and into the lungs is equivalent to outdoors air (i.e. 20.94% O2; 0.03% CO2; 78.94% nitrogen, and other traces).
The cover-up will not lower the ratio of O2 in the air you inhale and exhale, nor would it reduce the incomplete pressure of air much like that bought at 'high' altitude, so that it shouldn't be considered a hypoxic training help.
Most Gas masks cover at least the nostril and mouth and show an air filtering canister or a tiny hole that restricts air flow.
It has the result of increasing respiration resistance, particularly if ventilation rates deal with and exceed the top limit of the particular respirator was created to provide; most commercial respirators are designed for air moves of around 85 liters/min.
Compare this with the standard ventilation of resting humans (6 to 7 l/min) and the ones heavily working out (120 to 140 l/min).
Out of this, you can view a respirator will exert little physiological effect during slumber or moderate depth exercise, however, your ventilation rate will probably go beyond the maximal ventilation capacity of the cover up if you are exercising heavily, which can impact your physiology and performance.