A group of Italian researchers reports in the November issue of the Journal of Applied Physiology that while breathing a low-density mixture of 79% helium and 21% oxygen (called heliox), the length of time that 12 COPD patients could do real exercise was 9 minutes, versus only 4.2 minutes for 12 patients breathing regular air (79% nitrogen/21% oxygen). And the exercise involved wasn't trivial: The subjects cycled "until exhaustion" at a rate of 50 rpm at 80% of their maximal rate measured several days earlier while on air.
COPD: 4th leading cause of death in world and U.S., and rising
The World Health Organization estimates that chronic obstructive pulmonary disease (COPD, defined as emphysema and chronic bronchitis) as a single cause of death around the world shares fourth place with HIV/AIDS, following coronary heart disease, cerebrovascular disease and acute respiratory infection. WHO estimates that 2,740,000 people died of COPD worldwide in 2000; cigarette smoking is blamed for about 85% of cases.
According to the National Heart, Lung, and Blood Institute (NHLBI), COPD is the fourth leading cause of death in the U.S. and is projected to rise to third place for both men and women by the year 2020. NHLBI says 12.1 million Americans 25 and older were diagnosed with COPD in 2001. Estimated cost of COPD in 2002 was $32.1 billion, of which $18 billion were direct costs.
COPD is characterized by shortness of breath (dyspnea) and exercise intolerance. Among severely affected patients, especially those with emphysema, the inabil