Lung Function Improved as Patients Increased Strenuous Daily Physical Activity, Study Says

Replacing 30 minutes each day of sedentary time spent sleeping or sitting with strenuous or strength-building physical activity improved lung function in individuals with obstructive lung diseases, according to a study in Health Reports.

The study was the first to assess the effects of replacing sedentary time with different levels of physical activity on measures of lung function among adults with and without obstructive lung disease. For the purposes of the study, participants who did not have an obstructive lung disease were referred to as “healthy adults.” Those who reported having asthma, chronic obstructive pulmonary disease (COPD), or were below the lower limit of normal (LLN) for forced expiratory volume in 1 second (FEV₁) were considered to have an obstructive lung disease.

Data were used from participants of the Canadian Longitudinal Study on Aging, a random, stratified sample of 51,338 Canadian men and women 45 to 85 years old. Participants were recruited from 2012 to 2015. Only individuals with complete data for spirometry, sleep, physical activity,and sedentary time were included in the study. Individuals who had taken a bronchodilator 6 or 12 hours before spirometry was assessed and those with sleep disorders or lung cancer were excluded.

The final sample size was reduced to 18,105 individuals after accounting for data on all covariates, which included total pack years smoking cigarettes, height, weight, ethnicity, and whether they were retired. Of these participants, 1822 had asthma, 609 had COPD and 1494 were below the LLN for FEV₁.

Researchers evaluated lung function according to spirometry. Levels of physical activity and time spent sitting were assessed using a modified version of the Physical Activity Scale for the Elderly. Researchers performed isotemporal substitution analysis to examine the effects of replacing 30 minutes per day of one movement behavior with another, while keeping the total time constant. Separate analyses were conducted for healthy adults and individuals with an obstructive lung disease.

Spirometry was measured using a TrueFlow EasyOne Air spirometer. Data values on FEV₁ and forced vital capacity (FVC) were gathered using maximal inspiratory and expiratory measurement methods. Participants self-reported whether a doctor ever diagnosed them with COPD, asthma, emphysema, chronic bronchitis, or other chronic lung changes due to smoking. Those with obstructive lung disease had lower lung function, were less physically active, and had higher body mass indexes than those without any lung disease.

In all participants, both those considered healthy adults and those with an obstructive lung disease, all physical activity variables were positively associated with FEV₁ and FVC while time spent sitting was negatively associated with FEV₁ and FVC. Researchers found that FEV 1 increased when healthy individuals replaced 30 minutes per day spent sitting with 30 minutes of any type of physical activity or sleep. Participants with an obstructive lung disease saw an increase in FEV₁ when they replaced 30 minutes per day spent sitting or sleeping with 30 minutes of strenuous or strength-building physical activity.

Healthy adult participants demonstrated an increase of 0.2 to 0.8 percentage points of improvement in lung function outcomes after replacement of sedentary time with physical activity or sleep. Individuals with a chronic obstructive lung disease demonstrated 0.9 to 1.2 percentage points of improvement in lung function outcomes after replacement of sedentary time with strenuous physical activity or strengthening activities.

Data supported the perception that movement behaviors are predictors of lung function and are crucial in preventing and managing chronic obstructive lung diseases. The additive effect of these movement behaviors may lead to significant improvements in lung function and greatly reduce age-related decline in lung function.

Researchers suggest counselling individuals that have, or are at risk for developing, an obstructive lung disease on movement behaviors could lead to improvements in their lung function. They believe that this finding has implications for clinical practice.

Reference

Dogra S, Good J, Gardiner PA, et al; Effects of replacing sitting time with physical activity on lung function: an analysis of the Canadian longitudinal study on aging. Health Rep. 2019;30(3). doi: 10.25318/82-003-x201900300002-eng.