The impact of sleep duration on physical activity in daily life in patients with idiopathic pulmonary fibrosis

BACKGROUND

Despite the high prevalence of sleep disturbances in idiopathic pulmonary fibrosis (IPF), the relationship between physical activity in daily life (PADL) and sleep in this population remains unclear.

OBJECTIVES

Investigate the impact of sleep on different domains of PADL in IPF and characterize their PADL profile.

METHODS

Sixty-seven participants (thirty-three with IPF and thirty-four healthy subjects [control group]) were included. The subjects underwent assessments of pulmonary function, exercise capacity, respiratory and peripheral muscle strength, PADL, sleep, dyspnea, and health-related quality of life. PADL and sleep measures were assessed using an activity monitor (Actigraph®, wGT3x-BT). Associations between sleep and PADL were done using correlation and regression models.

RESULTS

In the IPF, sleep duration at night associated significantly with step counts, sedentary, light, and moderate-to-vigorous physical activity (MVPA) (-0.82 ≤ R ≤ 0.43; p < .05 for all). Lung function and sleep partially explained PADL variables (0.19 ≤ R2 ≤ 0.65, p < .05 for all). Compared to controls, the IPF subjects presented lower step counts, less time spent in MVPA, standing position, and more time spent in lying position (p < .05, for all).

CONCLUSIONS

Sleep duration is associated with PADL in IPF. The PADL profile of patients is worse than in control subjects.

Profile and determinants of daily physical activity objectively assessed in university students

BACKGROUND

The aim of this study was to quantify and compare physical activity (PA) levels of university students from different fields of study, and to investigate its correlates.

METHODS

221 students (111 female, 20 [18-23] years), from different study fields were cross-sectionally assessed for daily PA (pedometer), cardiorespiratory fitness (20 m Shuttle Run Test-20mSRT), health-related quality of life (HRQoL), anxiety and depression symptoms.

RESULTS

In general, 60% of the students were physically active (>8000 steps/day), presented good HRQoL and cardiorespiratory fitness, minimal symptoms of depression and moderate of anxiety. The highest PA level was observed in students from physical education and sport sciences, and the lowest in those from social sciences (median [IQR]: 9882 [8435-13510] versus 7593 [6070-9753] steps/day, respectively; P<0.01). Male students were more active than female. Steps/day was moderately associated with VO<inf>2</inf>max (r=0.42), VO<inf>2</inf>%pred (r=0.41) and distance achieved in the 20mSRT (r=0.43) (P<0.0001 for all), and weakly associated with anxiety symptoms (r=-0.20; P=0.004) and HRQoL domains (0.15<r<0.21; P<0.05). Distance achieved in the 20mSRT was the only determinant of steps/day (adjusted R2=0.22; P<0.0001).

CONCLUSIONS

Most university students can be considered as physically active. In these young adults, lower PA level correlates moderately with worse cardiorespiratory fitness and weakly with worse HRQoL and anxiety symptoms.

Home monitoring of breathing rate in people with chronic obstructive pulmonary disease: observational study of feasibility, acceptability, and change after exacerbation

Telehealth programs to promote early identification and timely self-management of acute exacerbations of chronic obstructive pulmonary diseases (AECOPDs) have yielded disappointing results, in part, because parameters monitored (symptoms, pulse oximetry, and spirometry) are weak predictors of exacerbations.

Application of Mixed Effects Limits of Agreement in the Presence of Multiple Sources of Variability: Exemplar from the Comparison of Several Devices to Measure Respiratory Rate in COPD Patients

Introduction

The Bland-Altman limits of agreement method is widely used to assess how well the measurements produced by two raters, devices or systems agree with each other. However, mixed effects versions of the method which take into account multiple sources of variability are less well described in the literature. We address the practical challenges of applying mixed effects limits of agreement to the comparison of several devices to measure respiratory rate in patients with chronic obstructive pulmonary disease (COPD).

Methods

Respiratory rate was measured in 21 people with a range of severity of COPD. Participants were asked to perform eleven different activities representative of daily life during a laboratory-based standardised protocol of 57 minutes. A mixed effects limits of agreement method was used to assess the agreement of five commercially available monitors (Camera, Photoplethysmography (PPG), Impedance, Accelerometer, and Chest-band) with the current gold standard device for measuring respiratory rate.

Results

Results produced using mixed effects limits of agreement were compared to results from a fixed effects method based on analysis of variance (ANOVA) and were found to be similar. The Accelerometer and Chest-band devices produced the narrowest limits of agreement (-8.63 to 4.27 and -9.99 to 6.80 respectively) with mean bias -2.18 and -1.60 breaths per minute. These devices also had the lowest within-participant and overall standard deviations (3.23 and 3.29 for Accelerometer and 4.17 and 4.28 for Chest-band respectively).

Conclusions

The mixed effects limits of agreement analysis enabled us to answer the question of which devices showed the strongest agreement with the gold standard device with respect to measuring respiratory rates. In particular, the estimated within-participant and overall standard deviations of the differences, which are easily obtainable from the mixed effects model results, gave a clear indication that the Accelerometer and Chest-band devices performed best.

Long-term effects of a program to increase physical activity in smokers

BACKGROUND

Programs aimed at increasing physical activity in daily life (PADL) have generated growing interest to prevent the deleterious effects of physical inactivity. Recent literature has shown that a short-term protocol using pedometers increased PADL in smokers with normal lung function. However, the long-term effects of such a protocol were not yet studied. The objective of this study was to evaluate the results of 1-year follow-up after a program aimed at increasing PADL in smokers with normal lung function.

METHODS

Twenty-four smokers were followed (15 men; mean [interquartile range (IQR)], 51 [41-57] years of age; BMI, 26 [22-29] kg/m2; 20 [20-30] cigarettes/d). Subjects were assessed at baseline, immediately after completion of the program, and 1 year later for PADL, lung function, 6-min walking distance (6MWD), smoking habits, quality of life, anxiety, and depression. The 5-month program used pedometers and informative booklets as interventions.

RESULTS

The gains achieved after the program were maintained in the long term: steps/d (postprogram vs 1-year follow-up, mean [IQR]: 10,572 [9,804-12,237] vs 10,438 [9,151-12,862]); 6MWD (625 [530-694] m, 88 [81-97] % predicted vs 609 [539-694] m, 89 [81-96] % predicted), anxiety (34 [26-41] points vs 35 [36-47] points) and depression (6 [2-9] points vs 5 [2-11] points) (P > .05 for all). One year after the program, 20% of the subjects had quit smoking.

CONCLUSIONS

In smokers with normal lung function, improvements in daily physical activity, exercise capacity, anxiety, and depression obtained through a 5-month program aimed at increasing physical activity are sustained 1 year after completion of the program. Furthermore, such a program can contribute to smoking cessation in this population.