Diurnal Physical Activity Patterns in Patients With Chronic Obstructive Pulmonary Disease.

PURPOSE: People with chronic obstructive pulmonary disease (COPD) have reduced physical activity (PA) levels compared with healthy controls. The pattern of their PA level during the day is much less documented. A better understanding of these diurnal PA patterns could help optimize interventions targeting PA levels in this population. The aim of this study was to examine, in patients with COPD, diurnal PA patterns using accelerometer data and different approaches to data handling (arbitrary, mealtime, equal tertiles). METHODS: Fourteen COPD patients (aged 71 ± 9 yr; forced expiratory volume in 1 sec [FEV1]: 58% ± 13% predicted) completed the study. Daily PA was assessed via accelerometry for 7 d, 24 hr/d. Diurnal PA patterns were evaluated using an arbitrary (08:00-12:00, 12:01-16:00, 16:01-20:00), mealtime (wake time-lunchtime, lunchtime-suppertime, suppertime-bedtime), and equal tertiles (tertiles 1, 2, and 3) approaches. Results were interpreted on the basis of descriptive statistics and effect sizes (Cohen f) for time-of-day changes in PA. RESULTS: Regardless of the handling approach used, mean PA levels decreased in the evening and the effect size for time-of-day changes in PA level was large (f = 0.97; 1.82; and 1.66 for the arbitrary, mealtimes, and tertiles approaches, respectively). The observation of a decrease in the evening was highly homogeneous across our sample, particularly with the mealtime and equal tertiles handling approach. CONCLUSION: Results from this study support prior findings that PA levels decrease substantially in the evening in patients with COPD, thereby providing a better understanding of within-day PA behavior and offering valuable insight into interventions targeting PA.

Diurnal Variations in Psychological Distress in Chronic Obstructive Pulmonary Disease.

PURPOSE: The aim of this study was to investigate the association between depressive symptoms severity and amplitude of diurnal variations in depression symptoms in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Prospective, observational proof-of-concept study. METHODS: Fourteen participants with moderate/severe COPD completed a 20-item Center for Epidemiologic Studies Depression Scale (CES-D) estimating depressive symptoms severity. Throughout one week, the four-item very short version of the CES-D was completed every day in the morning, afternoon, and evening. FINDINGS: Strong positive correlations were observed between depressive severity and the mean range of diurnal variations in positive (r = .61) and depressed affects (r = .67), somatic complaints (r = .82), and disturbed interpersonal relationships (r = .71). CONCLUSION: In COPD patients, a greater diurnal variation in depression symptoms was associated with greater depression severity. This relationship seems independent of COPD severity. CLINICAL RELEVANCE: Diurnal variation in the symptoms of depression is a new method of identifying depression severity in COPD.

Acute responses to exercise training and relationship with exercise adherence in moderate chronic obstructive pulmonary disease.

The objectives of our study were to (i) compare, in chronic obstructive pulmonary disease (COPD) patients, acute responses to continuous training at high intensity (CTHI), continuous training at ventilatory threshold (CTVT) and interval training (IT); (ii) examine associations between acute responses and 12-week adherence; and (iii) investigate whether the relationship between acute responses and adherence is mediated/moderated by affect/vigour. Thirty-five COPD patients (forced expiratory volume in 1 second = 60.2 ± 15.8% predicted), underwent baseline assessments, were randomly assigned to CTHI, CTVT or IT, were monitored throughout about before training, and underwent 12 weeks of exercise training during which adherence was tracked. Compared with CTHI, CTVT was associated with lower respiratory exchange ratio, heart rate and respiratory rate (RR), while IT induced higher [Formula: see text], [Formula: see text]maximal voluntary ventilation, RR and lower pulse oxygen saturation. From pre- to post-exercise, positive affect increased (F = 9.74, p < 0.001) and negative affect decreased (F = 6.43, p = 0.005) across groups. CTVT reported greater end-exercise vigour compared to CTHI (p = 0.01) and IT (p = 0.02). IT exhibited lowest post-exercise vigour (p = 0.04 versus CTHI, p = 0.02 versus CTVT) and adherence rate (F = 6.69, p = 0.004). Mean [Formula: see text] (r = -0.466, p = 0.007) and end-exercise vigour (r = 0.420, p = 0.017) were most strongly correlated with adherence. End-exercise vigour moderated the relationship between [Formula: see text] and adherence (ß = 2.74, t(32) = 2.32, p = 0.03). In summary, CTHI, CTVT and IT improved affective valence from rest to post-exercise and induced a significant 12-week exercise training effect. However, they elicited different acute physiological responses, which in turn were associated with differences in 12-week adherence to the target training intensity. This association was moderated by acute end-exercise vigour.

Clinical impact of time of day on acute exercise response in COPD.

The purpose of this pilot study was to determine the impact of time of day on the acute response to incremental exercise in chronic obstructive pulmonary disease (COPD). Fourteen subjects (nine men) aged 71 ± 7 years with moderate to severe airflow obstruction (FEV1: 58 ± 13% predicted) followed a counterbalanced randomized design, performing three symptom-limited incremental cycling tests at 8:00, 12:00, and 16:00 hours on different days, each preceded by a spirometry. COPD medications were withdrawn prior to testing. No overall time effect was found for peak exercise capacity (p = 0.22) or pulmonary function (FEV1, p = 0.56; FVC, p = 0.79). However, a large effect size (f = 0.48) was observed for peak exercise capacity and several pulmonary function parameters. For peak exercise capacity, the average within-subject coefficient of variation was 5.5 ± 3.9% and the average amplitude of change was 7 ± 5W. Seven subjects (50%) showed diurnal changes at levels equal to or beyond the minimal clinically important difference for both peak exercise capacity and pulmonary function. In this sub-group, peak exercise capacity was greatest at 16:00 hours (p = 0.03, ƒ = 1.04). No systematic time-of-day effect on peak exercise capacity was obtained in COPD patients in the present pilot study. However, based on the observed effect size and on the average amplitude of change and within-subject variations seen across testing times, the guidelines recommendation that time of day be standardized for repeat exercise testing in COPD should be maintained.

Using continuous data tracking technology to study exercise adherence in pulmonary rehabilitation.

Pulmonary rehabilitation (PR) is an important component in the management of respiratory diseases. The effectiveness of PR is dependent upon adherence to exercise training recommendations. The study of exercise adherence is thus a key step towards the optimization of PR programs. To date, mostly indirect measures, such as rates of participation, completion, and attendance, have been used to determine adherence to PR. The purpose of the present protocol is to describe how continuous data tracking technology can be used to measure adherence to a prescribed aerobic training intensity on a second-by-second basis. In our investigations, adherence has been defined as the percent time spent within a specified target heart rate range. As such, using a combination of hardware and software, heart rate is measured, tracked, and recorded during cycling second-by-second for each participant, for each exercise session. Using statistical software, the data is subsequently extracted and analyzed. The same protocol can be applied to determine adherence to other measures of exercise intensity, such as time spent at a specified wattage, level, or speed on the cycle ergometer. Furthermore, the hardware and software is also available to measure adherence to other modes of training, such as the treadmill, elliptical, stepper, and arm ergometer. The present protocol, therefore, has a vast applicability to directly measure adherence to aerobic exercise.