O6.5 Physical activity and sedentary behaviour

Physical activity is defined as any bodily movement generated by skeletal muscle that results in energy expenditure above resting levels and is often classified as light, moderate or vigorous intensity according to the energy level required (Garber 2011). In its broadest form, physical activity encompasses exercise (physical activity)  that is planned, structured and repetitive, undertaken with the aim of improving or maintaining physical fitness and for health benefits), sports, and physical activity done as part of daily living, work, leisure and transportation.

It is well-established that people with COPD participate in low levels of physical activity during daily life. Data from meta-analyses indicate that, on average, people with COPD participate in 57% of the total duration of physical activity undertaken by healthy controls (Vorrink 2011). Reductions in physical activity commence early in the COPD disease trajectory (Waschki 2015). Over time, levels of physical activity substantially decline across all severity stages of COPD and this decline is accompanied by deterioration in lung function and health status (Waschki 2015).  Levels of physical activity are reduced further during hospitalisation for an exacerbation of COPD (Pitta 2006).  An Australian study assessed physical activity in 50 individuals during hospitalisation for an exacerbation of COPD, and at 1 and 6 weeks following discharge (Tsai 2016). Although there was a significant improvement in physical activity at one week following discharge when compared to activity levels during admission, the level of physical activity at 6 weeks post-discharge showed no further significant improvement (Tsai 2016).

Low levels of physical activity are associated with increased mortality and exacerbations in people with COPD (Gimeno-Santos 2014) [evidence level I]. In one cohort study of 341 patients hospitalised for the first time with a COPD exacerbation, regular physical activity was related to a higher diffusing capacity of lung for carbon monoxide (DLCO) test, expiratory muscle strength, exercise capacity (6-minute walk distance (6MWD) and VO2 peak) as well as to lower levels of systemic inflammation, after adjusting for confounders (Garcia-Aymerich 2009) [evidence level III-2].  In a population-based sample of 2,386 individuals with COPD who were followed for a mean of 12 years, those who performed some level of regular physical activity had a significantly lower risk of COPD admissions or mortality than sedentary individuals (Garcia-Aymerich 2006) [evidence level III-2].

Regular physical activity is recommended for all individuals with COPD (Garcia-Aymerich 2009). In the absence of instruction from a health professional (i.e. physiotherapist, exercise physiologist), individuals with COPD should be encouraged to be physically activity (i.e. engage in at least moderate PA for 30 minutes on 5 days each week, e.g. walking) and participate in activities of daily living that require the use of muscle strength (e.g. lifting, squatting to complete tasks such as gardening) as well as doing activities such as bowls, golf, swimming and Tai Chi that they enjoy.

There is some evidence that interventions comprising physical activity counselling, especially when combined with coaching, can produce modest increases in physical activity in people with COPD however the quality of the evidence was rated as very low (Mantoani 2016) [evidence level I]. Physical activity behavioural modification interventions of 4 to 24 weeks duration that employed a step counter and dynamic target goal setting had a positive effect on steps per day compared to usual care (n=13 studies, 1535 participants, mean difference 1035 steps/day, 95% CI 576 to 1493) (Megaritis 2023) [evidence level I] and this surpassed the previously reported MCID of 350 to 1100 steps/day Teylan 2019).

A randomised controlled trial carried out in Spain in people with moderate COPD (predominantly male) showed a significant increase in physical activity (mean difference 947 steps/day (95% CI 184 to 1731)) at the 12-month follow-up (per protocol analysis) in a group that received a multicomponent Urban Training intervention compared to a group that received usual care (Arbillaga-Etxarri 2018).  Key components of the intervention included behavioural techniques and motivational interviewing, maps of validated walking trails of different intensities, pedometer and calendar to record physical activity, text messages every 2 weeks and option to participate in a monthly supervised walking group. No between group differences were seen in any of the secondary outcomes that included 6MWD, QoL and severe exacerbations.

Supervised exercise training alone or within the context of a pulmonary rehabilitation program has been shown to produce significant but small increases in physical activity, however the benefits are inconsistent and overall the quality of the evidence was rated very low (Mantoani 2016, Megaritis 2023) [evidence level I]. A systematic review and meta-analysis (Lahham 2016) found that activity counselling, when added to pulmonary rehabilitation, increased physical activity as measured by daily step count, and that this was both significant and exceeded the minimum important difference for daily step count (mean difference 1,452 daily steps, 95% CI 549 to 2,356). Physical activity promotion with a wearable activity monitor-based intervention (i.e., pedometer or accelerometer incorporated as a tool to monitor and provide feedback on step-count throughout the intervention), improved steps per day (median (IQR) 1153 (791-3199) steps per day) compared with usual care in a systematic review and meta-analysis (Reilly 2023) [evidence level I]. Further studies are needed, but physical activity counselling in the context of a pulmonary rehabilitation program shows promise in terms of increasing physical activity in daily life.

In addition to low levels of physical activity, there is growing recognition that people with COPD spend a large proportion of their waking hours in sedentary behaviours. Hunt et al (Hunt 2014) defined as those behaviours which are undertaken in a sitting or reclined posture and have low energy requirements (e.g. watching television, reading, playing cards, sitting at a computer) (Sedentary Behaviour Research 2012). People with COPD who accumulate the greatest sedentary time during daily life are more likely to live with someone else and be characterised by more frequent exacerbations, lower exercise capacity, long-term oxygen use, lower motivation for exercise, and the presence of physical comorbidities such as obesity, musculoskeletal or neurological conditions (Hartman 2013, McNamara 2014).

In the general population, data from several large longitudinal studies have reported the deleterious health consequences (e.g. both all-cause and cardiovascular mortality) of increased sedentary time (Dunstan 2010, Thorp 2011) [evidence level I]. Sedentary behaviour defined as more > 8.5 hrs/ day spent in sedentary behaviour in a cohort of 101 Brazilian COPD patients was an independent risk factor for mortality (Furlanetto 2017) [evidence level III]. Furthermore, data collected in 76,688 people from Japan, who were followed for 19.4 years show that, when compared with men who watched television for < 2 hours/day, men who watched television for ≥ 4 hours/day had an increased risk of COPD-related mortality (HR 1.63; 95% CI 1.04 to 2.55). However, this relationship was not observed in females (HR 0.84; 95% CI 0.29 to 2.48) (Ukawa 2015). Data collected in 223 people with COPD as part of the National Health and Nutrition Examination Survey (NHANES), showed modest positive associations between sedentary time and markers of cardiometabolic risk such as waist circumference and fasting glucose levels (Park 2014).

Given that people with COPD accumulate large amounts of sedentary time and this may have deleterious health consequences, reducing sedentary time would seem to be an appropriate lifestyle goal in this population. Compared with the goal of increasing physical activity, particularly moderate or vigorous intensity physical activity, the goal of reducing sedentary time by increasing light intensity physical activity is likely to be more feasible in those with marked reductions in exercise capacity who are limited by dyspnoea during activities of daily living (Cavalheri 2016, Hill 2015). Of note, in people with COPD, greater participation in light intensity physical activity, such as slow walking, has been reported to reduce the risk of respiratory-related hospitalisations (Donaire-Gonzalez 2015).  There is a need to identify approaches that are effective at reducing sedentary time in people with COPD, and most importantly, whether any reduction in sedentary time impacts health outcomes in this population.

The table in Appendix 4 provides some strategies aimed at avoiding prolonged sedentary time