I've been using the O2 Trainer for about 2 months now. And ever since I've been using it on a regular basis I haven't had an asthma attack. Now this is a big deal for me because I've had asthma all my life, I'm 40 years old now, and I've just come to live with it. When I was a kid it was really bad and I was hospitalized a lot. So much that my family almost went bankrupt and I almost didn't make it pass junior high because of so many absences. After junior high and towards high school, I got stronger from swimming and martial arts, but the asthma was always there. I never met anyone who had asthma worse than me. So it's been nothing short of a miracle for me that I haven't had any asthma for almost 2 months now. I workout more now, and I feel more confident in my cardio. I like that it makes my workouts shorter because it makes it more challenging. Here is a clip of me using it. Bas Rutten's wife was kind enough to post this video on their O2 Trainer Facebook page!