High doses of vitamin D supplementation on top of a standard rehabilitation program may improve the outcome in terms of exercise capacity and respiratory muscle strength of patients with chronic obstructive pulmonary disease (COPD), according to a new study from Belgium.
In the randomized controlled trial, 50 COPD patients with a history of exacerbations who had been referred for rehabilitation were randomly assigned to receive either a monthly dose of 100,000 IU vitamin D or placebo (1). All patients participated in a pulmonary rehabilitation program for three months. At the beginning of the study and again at the completion of the rehabilitation program, peripheral and respiratory muscle strength, exercise capacity and vitamin D levels were measured. At the end of the study, researchers found that patients treated with vitamin D had a significant improvement in exercise capacity and respiratory muscle strength compared to those in the placebo group.
The researchers commented that vitamin D deficiency is common among patients with COPD, and is often associated with lack of exposure to sunlight and diet. COPD patients often have limited physical activity as a result of breathing difficulties associated with the disease, which also may result in less exposure to sunlight. Low levels of vitamin D in the blood have been related with muscle weakness, a major target for respiratory rehabilitation and increased risk of falls. The scientists concluded that the study results would support the idea that correcting vitamin D deficiency by adding high doses of vitamin D supplements to training programs allows COPD patients to achieve better results from rehabilitation, including improvements in muscle strength and exercise capacity. In the U.S. the recommended daily allowance of vitamin D is 600 IU daily for adults up to age 70 and 800 IU daily for adults over age 70.
Chronic obstructive pulmonary disease is the co-occurrence of chronic bronchitis and emphysema, a pair of commonly co-existing diseases of the lungs in which the airways become narrowed making it increasingly difficult to breathe. COPD is considered a respiratory disease but has important non-respiratory consequences, such as osteoporosis, cardiovascular disease and muscle weakness. These consequences eventually are negatively influenced by physical inactivity, which, along with exercise intolerance, is a common feature among patients with COPD and is proven to be related to mortality.