Hi I'm new in this forum A few years ago, I purchased the 'Expand-a-lung' (no big investment: $29) just to give it a try...I don't have any testing equipment to see if there were monumental or minimal improvements in my VO2, but I did see an increase in actual resistance use....meaning that my ability to inhale longer and exhale longer improved; all the while increasing the resistance...
BFD..I can't see how it would be harmful...for $29, I went for it....would I do it again? Yep; although I haven't used it in almost a year, but will begin this week... fun to drive long distances and have that thing stuck in your mouth you get some confused stares along the expressway...
Final note...my doctor does comment that I have twice the lung capacity of people my age (67yo) This may be attributed to biking also...
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