Study Suggests Physical Activity Measurements Are a Valuable Tool in Assessing Adult Cystic Fibrosis Patients’ Aerobic Fitness

An international research team led by researchers at the Sapienza University of Rome in Italy reported that the assessment of daily physical activity in adult patients with cystic fibrosis (CF) could be used as a valuable tool to determine their aerobic fitness and exercise performance. The study was published in the journal BMC Pulmonary Medicine and is entitled “Relationship between daily physical activity and aerobic fitness in adults with cystic fibrosis.”

CF is a life-threatening genetic disease in which a defective gene causes the body to form unusually thick, sticky mucus that can result in serious respiratory and gastrointestinal manifestations.

Parameters that reflect the aerobic fitness of the individual, like the peak oxygen uptake (the maximum rate of oxygen consumption), maximal work rate and ventilator equivalents for oxygen uptake, measured during incremental cardiopulmonary exercise testing (CPET) are significant predictors of mortality in CF patients. Several studies have underscored the importance of using exercise testing in CF patients, and CF guidelines even recommend an annual assessment. However, the use of CPET in the clinical practice is still underused, mainly due to the lack of patients’ motivation to perform maximal exercise tests and the lack of adequately trained staff to conduct the test. Different methods to assess exercise capacity in CF are therefore needed.

In the study, researchers analyzed the possibility of measuring physical activity through a portable accelerometer as an additional tool to CPET in the assessment of CF aerobic state. The team analyzed both physical activity and exercise fitness at sub maximal and maximal levels in 30 adult CF patients who were clinically stable along with 15 healthy controls through an incremental CPET on a cycle ergometer. Physical activity was evaluated with the SenseWear Pro3 Armband accelerometer.

Researchers found that moderate and moderate-plus-vigorous physical exercise was related to oxygen uptake and work rate at sub maximal exercise. The oxygen uptake profile was found to be similar between CF patients and healthy controls, except for peak values. Daily physical activity levels and parameters between the two groups at submaximal exercise were also found to be similar.

The research team concluded that the daily physical activity in adult CF patients positively correlated with the aerobic physical fitness, and that physical activity measurements can be considered a valuable tool when analyzing exercise performance in adult CF patients. The team suggests that physical activity measurements could be easily integrated into interventional exercise trials to improve exercise performance and the health condition of CF patients. Further studies are required to determine whether physical activity measurements are sensitive and accurate enough to detect early changes in CF exercise capacity as a way to monitor disease progression.