A recent observational study found that, regardless of disease severity, more than half of patients experienced COPD symptoms throughout the whole 24-hour day, and nearly 80% of patients reported experiencing symptoms during at least two parts of the day. The presence of symptoms is associated with worse health status, depression, anxiety, and poor sleep quality. Preserving or improving physical activity may have far-reaching benefits for hospitalization and mortality rates.
The well-defined symptoms commonly reported by patients with COPD include cough, sputum production, wheeze, and breathlessness. However, the impact of symptoms on an individual patient’s daily living activities varies depending on a number of factors, for example, their disease severity and comorbidities. The incidence and severity of symptoms also have a varying impact on a patient’s quality of life at different times of the day, with early morning and nighttime symptoms having a particularly detrimental influence on health status. The impact of COPD symptoms on a patient’s quality of life is often underestimated; for instance, 36% of patients who describe their symptoms as being mild-to-moderate also admit to being too breathless to leave the house.
Studies have shown that physical activity declines with advancing COPD, as patients with moderate-to-severe disease had lower activity levels than healthy controls. The most inactive patients were those on oxygen therapy. Activity levels start to decline early in disease progression; by the time patients reach moderate levels of airflow limitation (GOLD stage II), they are already starting to become inactive. The decline in physical activity in COPD sufferers may correlate with a range of factors, including airflow obstruction, dynamic lung hyperinflation, cardiac dysfunction, muscle deconditioning and quadriceps strength, and systemic inflammation.
The systemic consequences of COPD, such as muscle weakness and osteoporosis, commonly arise in inactive patients. Additionally, data suggest that patients with COPD who have low levels of physical activity are more likely to be admitted to hospital. Preserved levels of physical activity are related to a better prognosis in COPD. In two separate studies, patients with COPD who had different activity levels were followed for 3 years and 5–8 years. The probability of survival was significantly improved in those patients who were more active, even after correcting for lung function and exercise capacity. One of the studies concluded that the objective measurement of physical activity is the strongest predictor of all-cause mortality in patients.
Improving physical activity: an integrated approach
As in appropriately dosing medication, it is important that the level and timing of physical activity is guided by an overall rehabilitation strategy for the patient. Pulmonary rehabilitation therefore aims to improve the physical and psychological health of patients with chronic respiratory disease, and includes a focus on improving physical activity levels. Pulmonary rehabilitation techniques can include exercise training (under direct supervision or at home), behavior modification, and education of the patient about COPD.
Many patients with COPD find that their symptoms are at their worst in the early morning and at night. Symptoms such as coughing, general fatigue, and tiredness are commonly experienced in the morning, with 50% of patients with severe COPD experiencing these immediately upon waking on all or most days. Furthermore, 37% of all patients with COPD were woken up by their symptoms on at least 3 days per week. At night, patients experiencing symptoms such as fatigue, tiredness, and back pain stated their symptoms were worse than normal. To help alleviate early morning and nighttime symptoms, patients must ensure that they take their medication at the optimum time and physicians must advise patients on the most suitable time to take their medication. Bronchodilator therapy is known to improve exercise tolerance and exertional dyspnea in patients with COPD, but may also improve physical activity, as has recently been demonstrated for the LAMA aclidinium and for the LABA indacaterol.
[Based on the proceedings of a session at the 1st World Lung Disease Summit held in Lisbon on November 15–17, 2013, which brought together experts in the field of COPD.]
