Originally Posted by
erig007
Didn't say that.
Clue number 1:
when i breath through my mask part of my breath goes back into my lungs (i can notice the difference in terms of smell between my breath and fresh air). To be expected since when i expels some CO2 i have to create enough pressure for the CO2 to go through the mask valves. As you can guess not everything can go through.
Clue number 2:
i ride slower with my mask on. Get tired faster....
If you're using a mask, there's a very simple test you can do to see if it does anything. Wear a pulse oximeter while exercising with the mask on. For it to have an effect, your blood oxygenation has to drop below 93%. Pulse oximeters are quite inexpensive.