The effect of a regular walking program on dyspnoea severity and quality of life in normal weight, overweight, and obese patients with chronic obstructive pulmonary disease

Quantification of physical activities in daily life in patients with chronic obstructive pulmonary disease has increasing clinical interest. However, detailed comparison with healthy subjects is not available. Furthermore, it is unknown whether time spent actively during daily life is related to lung function, muscle force, or maximal and functional exercise capacity. We assessed physical activities and movement intensity with the DynaPort activity monitor in 50 patients (age 64 +/- 7 years; FEV1 43 +/- 18% predicted) and 25 healthy elderly individuals (age 66 +/- 5 years). Patients showed lower walking time (44 +/- 26 vs. 81 +/- 26 minutes/day), standing time (191 +/- 99 vs. 295 +/- 109 minutes/day), and movement intensity during walking (1.8 +/- 0.3 vs. 2.4 +/- 0.5 m/second2; p < 0.0001 for all), as well as higher sitting time (374 +/- 139 vs. 306 +/- 108 minutes/day; p = 0.04) and lying time (87 +/- 97 vs. 29 +/- 33 minutes/day; p = 0.004). Walking time was highly correlated with the 6-minute walking test (r = 0.76, p < 0.0001) and more modestly to maximal exercise capacity, lung function, and muscle force (0.28 < r < 0.64, p < 0.05). Patients with chronic obstructive pulmonary disease are markedly inactive in daily life. Functional exercise capacity is the strongest correlate of physical activities in daily life.

Information about the influence of regular physical activity on the course of chronic obstructive pulmonary disease (COPD) is scarce. A study was undertaken to examine the association between regular physical activity and both hospital admissions for COPD and all-cause and specific mortality in COPD subjects. From a population-based sample recruited in Copenhagen in 1981-3 and 1991-4, 2386 individuals with COPD (according to lung function tests) were identified and followed until 2000. Self-reported regular physical activity at baseline was classified into four categories (very low, low, moderate, and high). Dates and causes of hospital admissions and mortality were obtained from Danish registers. Adjusted associations between physical activity and hospital admissions for COPD and mortality were obtained using negative binomial and Cox regression models, respectively. After adjustment for relevant confounders, subjects reporting low, moderate or high physical activity had a lower risk of hospital admission for COPD during the follow up period than those who reported very low physical activity (incidence rate ratio 0.72, 95% confidence interval (CI) 0.53 to 0.97). Low, moderate and high levels of regular physical activity were associated with an adjusted lower risk of all-cause mortality (hazard ratio (HR) 0.76, 95% CI 0.65 to 0.90) and respiratory mortality (HR 0.70, 95% CI 0.48 to 1.02). No effect modification was found for sex, age group, COPD severity, or a background of ischaemic heart disease. Subjects with COPD who perform some level of regular physical activity have a lower risk of both COPD admissions and mortality. The recommendation that COPD patients be encouraged to maintain or increase their levels of regular physical activity should be considered in future COPD guidelines, since it is likely to result in a relevant public health benefit.

Accurate assessment of the amount and intensity of physical activity in daily life is considered very important due to the close relationship between physical activity level, health, disability and mortality. For this reason, assessment of physical activity in daily life has gained interest in recent years, especially in sedentary populations, such as patients with chronic obstructive pulmonary disease (COPD). The present article aims to compare and discuss the two kinds of instruments more commonly used to quantify the amount of physical activity performed by COPD patients in daily life: subjective methods (questionnaires, diaries) and motion sensors (electronic or mechanical methods). Their characteristics are summarised and evidence of their validity, reliability and sensitivity is discussed, when available. Subjective methods have practical value mainly in providing the patients' view on their performance in activities of daily living and functional status. However, care must be taken when using subjective methods to accurately quantify the amount of daily physical activity performed. More accurate information is likely to be available with motion sensors rather than questionnaires. The selection of which motion sensor to use for quantification of physical activity in daily life should depend mainly on the purpose of its use.