Abstract
BackgroundAccelerometry data are frequently analyzed without considering whether moderate-to-vigorous physical activities (MVPA) were performed in bouts of >10 minutes as defined in most physical activity guidelines. We aimed i) to quantify MVPA by using different commonly-applied physical activity guidelines, ii) to investigate the effect of bouts versus non-bouts analysis, and iii) to propose and validate a MVPA non-bouts cut-point to classify (in-) active subjects.MethodsHealthy subjects (n=110;62±6yrs) and patients with Chronic Obstructive Pulmonary Disease (COPD) (n=113;62±5yrs) wore an activity monitor for 7 days. Three Metabolic Equivalent of Task (MET) cut-offs and one individual target (50% VO2 reserve) were used to define MVPA. First, all minutes of MVPA were summed up (NON-BOUTS). Secondly, only minutes performed in bouts of >10 minutes continuous activity were counted (BOUTS). Receiver operating characteristic (ROC) curve analyses were used to propose and (cross-) validate new MVPA non-bout cut-points based on the criterion of 30 minutes MVPA per day (BOUTS). Likelihood ratios (sensitivity/[1-specificity]) were used to express the association between the proposed MVPA non-bout target and the MVPA bout target of 30 min*day-1.ResultsMVPA was variable across physical activity guidelines with lowest values for age-specific cut-offs. Selecting a METs cut-point corresponding to 50% VO2 reserve revealed no differences in MVPA between groups. MVPA’s analyzed in BOUTS in healthy subjects were 2 to 4 fold lower than NON-BOUTS analyses and this was even 3 to 12 fold lower in COPD. The MVPA non-bouts cut-point of 80 min*day-1 using a 3 METs MVPA threshold delivered positive likelihood ratios of 5.1[1.5-19.6] (healthy subjects) and 2.3[1.6-3.3] (COPD).ConclusionMVPA varies upon the selected physical activity guideline/targets and bouts versus non-bouts analysis. Accelerometry measured MVPA non-bouts target of 80 min*day-1, using a 3 METs MVPA threshold, is associated to the commonly-used MVPA bout target of 30 min*day-1.
Highlights
The increasing burden of a physically inactive lifestyle has become a worldwide public health problem since it is directly related to morbidity and mortality and does increase the health care costs [1]
This study showed that (i) the time spent in moderate to vigorous physical activities (MVPA) was variable across different physical activity guidelines with lowest values for agespecific cut offs (ACSM 2011)
Healthy subjects and patients with chronic obstructive pulmonary disease (COPD) spend less time in MVPA when only bouts of 10 minutes were considered. (ii) The proposed MVPA non-bouts cut-point of 80 min*day-1, using a 3 Metabolic Equivalents of Task (METs) MVPA threshold, was associated with the MVPA bouts cut-point of 30 min*day-1 in subjects with and without COPD
Summary
The increasing burden of a physically inactive lifestyle has become a worldwide public health problem since it is directly related to morbidity and mortality and does increase the health care costs [1]. The target of at least 30 minutes of MVPA per day, in bouts of at least 10 minutes, during at least 5 days of the week is proposed to distinguish active from inactive subjects [6,7]. The daily targets of ≥ 30 minutes of MVPA (bouts) and 1.7 PAL are commonly used and are embedded in two official physical activity recommendations by the World Health Organization [10,11]. The impact of using different physical activity guidelines and data analysis ((non-)bouts) along with the validation of the “new” proposed MVPA non-bout cut-point is important in patient populations with chronic disease, such as COPD. In a sample of healthy subjects and patients with COPD we aimed (i) to investigate to what extent the use of commonlyapplied physical activity guidelines and targets on MVPA provide different results, (ii) to investigate the effect of bouts versus non-bouts analysis on MVPA (iii) to propose and (cross-) validate a non-bout MVPA cut-point equivalent to the commonly-used 30 minutes (bouts) criterion and to validate this proposed MVPA non-bout cut-point in healthy subjects and in patients with COPD
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
