The new PowerLung ($64) is a cool new device designed to increase your lung capacity and strengthen the respiratory muscles that support your lungs for inhaling and exhaling. Just like strength training, the PowerLung adds adjustable resistance to both your inhalation and exhalation. In about ten minutes a day, while sitting or standing, just breathe into the PowerLung to efficiently workout your lungs. This is not only great for fitness training, sports, diving and swimming, it's also great for musicians, public performers and sufferers of mild asthma (check with doctor first). Wouldn't you like to be able to run faster, exercise easier, dive deeper, perform longer, train harder or just breathe better? Me too. (via The Green Head)

The Powerlung helps you train the muscles associated with breathing. By doing inhalation and exhalation exercises, you can increase your lung stamina and physical endurance. I would imagine that this would also be good for asthmatics or people with poor lung functions.