My POWERbreathe has made a remarkable difference in my life; I had completely given up running a few years ago due to my asthma and never being able to catch my breath. I discovered the POWERbreathe on Concept2's U.K. site and decided the research seemed sound and it was worth trying. The result? -- I have begun running again --with no problems in my breathing... I cannot thank you folks enough for this wonderful, elegant little gadget.