Training masks are junk science and dont work. If you want cardio fast, do cardio fast, I.e. any HIIT training.
Are you referring to those "gas mask" type things? I was thinking of getting one (after research of course), but I didn't want to look like a gimp when running through the forest....It's bad enough with my rubber suit. Good to know that it's a crock...you saved me some ££££.
you dont a mask, you can naturally control your breathing, i have a weiner dog that can do this as well. I have good cardio for a guy my age. chek out my log called body shot
How exactly are you judging your good cardio, hr recovery, VO2 figures, resting hr, power output at threshold?? How you perform in competition? The ironic thing is that the TS asked the question 4years ago i suspect he has build his cardio by now