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Cycling to better health, one leg at a time
20 January 2010
The Norwegian University of Science and Technology (NTNU)
People with chronic-obstructive pulmonary disease (COPD) often find themselves in a downward spiral when it comes to their health. COPD, which includes chronic bronchitis and emphysema, means that the elasticity of the lungs is destroyed.
One of the results of this loss of elasticity is that people with the disease find it difficult to completely exhale when they breathe. As a result, COPD patients are more likely to be sedentary, which in turn makes their physical condition even poorer. A series of new studies from Professor Jan Helgerud and co-workers at the Norwegian University of Science and Technology (NTNU) have found several ways to help improve a COPD patient’s overall fitness, which improves their quality of life. All it takes is a little extra oxygen, or cycling on a stationary bicycle, using just one leg at a time.
Increasing intensity using oxygen
Exercise places demands on the muscles, which in turn need the lungs to provide enough oxygen. This oxygen demand is at the crux of good training. For COPD patients who exercise, however, the lungs may have such a difficult time providing the oxygen they need that the oxygen saturation in their blood may drop below 88 percent.
One approach to help these patients is to provide them with extra oxygen when they exercise. In a study published online in the Scandinavian Journal of Medicine and Science in Sports in September 2009, Helgerud and co-workers at Faculty of Medicine, NTNU and St. Olavs Hospital in Trondheim have shown that when inhaled air contains 100% oxygen, and the blood becomes sufficiently saturated, COPD patients can actually exercise at the intensity that’s needed to provide optimal stimulation of the muscles and heart.
After 24 high-intensity training sessions where additional oxygen was supplied, COPD patients in the study had improved a key measure of cardiovascular fitness, maximal oxygen uptake (VO2 peak), by an average of 20 per cent. And the patients reported that their quality of life improved by 24 per cent in terms of their physical health status, and 35 per cent in their mental health status.
By improving their fitness, COPD patients used less of their maximum capacity, which makes training less of an effort. And because the effort required to breathe is reduced, that means patients are less limited overall by their disease. But what if training with extra oxygen simply isn’t an option? That’s where one-legged bicycling comes in.
Ride with one leg, rest the other
Siri Bjørgen, a newly minted PhD from the NTNU Faculty of Medicine’s Department of Circulation and Medical Imaging has published a series of studies with her colleagues showing that one-legged cycling can dramatically improve fitness in COPD patients. This is cycling with one leg while the other leg rests. The approach maximizes the supply of oxygen to the muscles while minimizing the effects of reduced lung capacity.
Essentially, exercising only one leg at a time enables the load on each leg to be increased without increasing the work that the lungs have to do.
In one study published in the European Journal of Applied Physiology late last year, one-legged cycling increased two measures of fitness, whole body VO2peak and peak work rate by 12 and 23 per cent, respectively, compared to two legged cycling, where improvements in the same measures were only 6 and 12 per cent. However, in a study published in December in the International Journal of Sports Medicine, Bjørgen and her colleagues reported that providing extra oxygen to COPD patients when they exercise using one-legged cycling doesn’t further increase the benefits of this approach.
Better shape - better life
Bjørgen says that the goal of improving fitness in COPD patients is that it allows them to participate in social life and perform everyday tasks such as to get the mail or go to the store. In fact, every participant in the study said that they felt that their quality of life had improved because they were in better physical shape.