Functional and psychological variables both affect daily physical activity in COPD: a structural equations model

BACKGROUND

Daily physical activity (DPA) level is reduced in patients with COPD. The aim of this study was to investigate the association of DPA with functional and psychological variables in these patients.

METHODS

155 COPD patients (102 males, median (IQR) age 62 years (54-69 years), predicted FEV1 60% (40-75%) were included. We assessed DPA (DigiWalker SW-200), functional capacity and psychological factors.

RESULTS

DPA level was significantly associated with all functional capacity variables and two psychological variables (Perceived Physical Ability Subscale, depression subscale of the Hospital Anxiety and Depression Scale). The six-minute walking distance and St. George Respiratory Questionnaire activity score explained 37% of the variance of DPA in a regression analysis. A structural equations model revealed that psychological variables indirectly explained DPA through functional capacity variables. DPA was stronger associated with functional capacity variables and weaker with psychological variables in patients with lower functional status than in patients with higher functional status.

CONCLUSIONS

Higher levels of DPA are associated with better functional capacity, but interestingly, DPA is also affected by psychological factors, though only indirectly, via functional capacity. The effect of specific treatment addressing psychological factors on DPA level and exercise tolerance needs further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT00614796.

Consequences of physical inactivity in chronic obstructive pulmonary disease

The many health benefits of regular physical activity underline the importance of this topic, especially in this period of time when the prevalence of a sedentary lifestyle in the population is increasing. Physical activity levels are especially low in patients with chronic obstructive pulmonary disease (COPD). Regular physical activity and an active lifestyle has shown to be positively associated with outcomes such as exercise capacity and health-related quality of life, and therefore could be beneficial for the individual COPD patient. An adequate level of physical activity needs to be integrated into daily life, and stimulation of physical activity when absent is important. This article aims to discuss in more detail the possible role of regular physical activity for a number of well-known outcome parameters in COPD.

Determinants of overweight and obesity in lung transplant recipients

BACKGROUND

Obesity-related diseases have been shown to affect post-lung transplantation survival. An estimated 30% of lung transplant recipients develop overweight.

OBJECTIVE

The aim of this study was to examine the possible determinants of large increases in weight after lung transplantation. The contribution of physical activity, food intake, and resting energy expenditure was examined in lung transplant recipients.

METHODS

In this cross-sectional study 21 overweight lung transplant recipients (11 men, mean age 57 ± 7 years; BMI 30 ± 3) and 21 normal-weight lung transplant recipients (11 men, mean age 56 ± 5 years; BMI 22 ± 3) were matched for disease, gender, age, prescribed medication, and time since lung transplantation. Physical activity was measured by a pedometer and a questionnaire; resting energy expenditure was measured by the ventilated-hood technique, and daily food intake by a dietician. Additionally, fat-free mass, lower-body strength, and fatigue were measured.

RESULTS

The overweight lung transplant recipients had a significantly lower number of steps per day (4,686 ± 3,266 vs. 7,524 ± 3,448 steps/day, p = 0.01) and a lower fat-free mass (64 ± 9 vs. 75 ± 6%, p < 0.05) compared to normal-weight recipients. Obese subjects had a lower percentage of predicted resting energy expenditure level compared to normal-weight recipients (90 ± 14 vs. 100 ± 14% predicted, p = 0.04).

CONCLUSION

Our data suggest that overweight in lung transplant recipients is associated with a lower fat-free mass and lower levels of physical activity and resting energy expenditure compared to normal-weight recipients.

Validation of the Dynaport Minimod during Sleep: A Pilot Study

To measure activity during sleep, polysomnography and actigraphy are often used. The DynaPort MiniMod measures movement intensity and body position day and night. The goal was to examine the validity of the DynaPort MiniMod in assessing physical activity and body posture during sleep. In Study A, 10 healthy participants slept with the DynaPort MiniMod and the Actiwatch for one night. In Study B, 8 participants suspected of having Obstructive Sleep Apnoea Syndrome slept for one night with the DynaPort MiniMod and underwent complete polysomnography as part of the typical care protocol. In Study A, there was a significant moderate correlation ( r = .70) between the movement scores of the Actiwatch and the DynaPort MiniMod. In Study B, a high intraclass correlation ( r = .84) between body posture scores of the DynaPort MiniMod and the polysomnography position sensor was observed. The DynaPort MiniMod is a valid measurement device for physical activity during sleep.

Cross-sectional assessment of daily physical activity in chronic obstructive pulmonary disease lung transplant patients

BACKGROUND

Information about daily physical activity of chronic obstructive pulmonary disease (COPD) lung transplant patients is relevant for evaluation of the functional recovery of physical capacity after lung transplantation. The objective of this study was to cross-sectionally assess daily physical activity, pulmonary function, physical fitness, fear of physical activity and motivation to exercise in COPD patients who were lung transplant candidates and lung transplant recipients.

METHODS

Fifteen COPD lung transplant candidates (5 men and 10 women, mean age 53 years, forced expiratory volume in 1 second [FEV(1)] 20% predicted) and 47 recipients (18 men and 29 women, mean age 55 years, FEV(1) 93% predicted, 39 bilateral and 8 unilateral transplants) were enrolled in this observational study. Daily physical activity was measured using a pedometer (Digiwalker SW-200) and the Short QUestionnaire to ASsess Health-enhancing physical activity (SQUASH). Physical fitness was measured by the sit-to-stand test and the arm curl test. Fear of physical activity and motivation to exercise were measured by the Tampa Scale for Kinesiophobia-Dutch version Questionnaire and the Exercise Self-Regulation Questionnaire.

RESULTS

Mean (+/-SD) number of steps per day in lung transplant recipients was higher compared with transplant candidates: 6,642 (+/-2,886) and 1,407 (+/-1,166), respectively (p < 0.05). Number of steps per day correlated significantly with FEV(1) (r = 0.32, p = 0.03) and lower body strength (r = 0.45, p = 0.002) in lung transplant recipients. There was no significant difference in daily physical activity, physical fitness, fear and motivation between bi- and unilateral transplant recipients.

CONCLUSION

Our data suggest that lung transplantation improves daily physical activity, lower body strength and FEV(1).

Enhancement of daily physical activity increases physical fitness of outclinic COPD patients: results of an exercise counseling program

OBJECTIVE

To investigate whether a 12-week pedometer-based exercise counseling strategy is feasible and effectively enhances daily physical activity in outclinic Chronic Obstructive Pulmonary Disease (COPD) patients who do not participate in a rehabilitation program in a controlled way.

METHODS

35 outclinic COPD patients (21 males, mean age 62 years, GOLD I-III, mean FEV(1)% predicted 64.7) were randomized for a 12-week individual pedometer-based exercise counseling program promoting daily physical activities or usual care. Daily physical activity (DigiWalker SW-200), physical fitness, health-related quality of life, self-efficacy, fatigue, depression and motivation to be physically active were assessed before and after the intervention.

RESULTS

After the intervention, COPD patients in the exercise counseling group showed a significant increase in their mean number of steps/day (from 7087 to 7872), whereas the usual care group showed a decrease (from 7539 to 6172). Significant differences favoring the exercise counseling group were demonstrated in arm strength, leg strength, health-related quality of life and intrinsic motivation to be physically active.

CONCLUSION

Our study shows that a 12-week pedometer-based exercise counseling strategy is feasible and effectively enhances daily physical activity, physical fitness, health-related quality of life and intrinsic motivation in outclinic COPD patients who do not participate in a rehabilitation program.

PRACTICE IMPLICATIONS

The feasibility of our exercise counseling strategy is good and patients were motivated to participate.