Methodological aspects for accelerometer-based assessment of physical activity in heart failure and health

Abstract

Background: For valid accelerometer-assessed physical activity (PA) data, several methodological aspects should be considered. We aimed to 1) visualize the applicability of absolute accelerometer cut-offs to classify PA intensity, 2) verify recommendations to measure PA over 7 days by examining inter-day variability and reactivity, 3) examine seasonal differences in PA, and 4) recommend during which 10 h day period accelerometers should be worn to capture the most PA in patients with heart failure (HEART) and healthy individuals (HEALTH).

Methods: Fifty-six HEART (23% female; mean age 66 ± 13 years) and 299 HEALTH (51% female; mean age 54 ± 19 years) of the COmPLETE study wore accelerometers for 14 days. Aim 1 was analyzed descriptively. Key analyses were performed using linear mixed models.

Results: The results yielded poor applicability of absolute cut-offs. The day of the week significantly affected PA in both groups. PA-reactivity was not present in either group. A seasonal influence on PA was only found in HEALTH. Large inter-individual variability in PA timing was present.

Conclusions: Our data indicated that absolute cut-offs foster inaccuracies in both populations. In HEART, Sunday and four other days included in the analyses seem sufficient to estimate PA and the consideration of seasonal differences and reactivity seems not necessary. For healthy individuals, both weekend days plus four other days should be integrated into the analyses and seasonal differences should be considered. Due to substantial inter-individual variability in PA timing, accelerometers should be worn throughout waking time. These findings may improve future PA assessment.

Trial registration: The COmPLETE study was registered at clinicaltrials.gov ( NCT03986892 ).

Keywords: Activity monitor; Leisure activities; Sedentary behavior; Wearing time.

Conflict of interest statement

None of the authors has any conflict to declare.

© 2021. The Author(s).

Figures

Fig. 1

Participant flow. GGIR is the R-package used for data processing [25]. Abbreviations: HEART, patients with heart failure; HEALTH, healthy individuals; CPET, cardiopulmonary exercise testing

Fig. 2

Cardiorespiratory response in % of V.O2peak to exercising at 2, 3, and 6 METs across the age spectrum (20 to 91 years) for patients with heart failure (HEART) and healthy individuals (HEALTH). The age of all participants is displayed on the x-axes. The relative intensity in % of the subjects’ V.O2peak that would be required to exercise at the three absolute intensities (2, 3, and 6 METs) is depicted on the y-axes. Intensity categories are marked by the dashed lines. LPA is defined as 0 to < 46% of V.O2peak, MPA as 46 to < 64% of V.O2peak, and VPA as 64 to 100% of V.O2peak.2 The hatched area symbolized the intensity that cannot be maintained for a prolonged time, as it exceeds the individual’s cardiorespiratory fitness. Abbreviations: LPA, light physical activity; MPA, moderate physical activity; VPA, vigorous physical activity; V.O2peak, peak oxygen uptake

Fig. 3

Mean physical activity patterns ± SE for each day of the week for patients with heart failure (HEART) and healthy individuals (HEALTH), respectively. Dotted lines in the MVPA graph additionally illustrate minutes accumulated in bouts of ≥ 10 min. Abbreviations: LPA, light physical activity; MPA, moderate physical activity; MVPA, moderate-to-vigorous physical activity; VPA, vigorous physical activity; TPA, total physical activity; SE, standard error

Fig. 4

Violin plots of daily physical activity patterns of patients with heart failure (HEART) and healthy individuals (HEALTH) for each season of the year. Bold horizontal lines in the violin plots depict the median and dotted lines represent 25th and 75th percentiles. Number of days included in the analyses for each season of the year for HEART and HEALTH, respectively: Spring (n = 269 & 1589), Summer (n = 157 & 813), Autumn (n = 151 & 803), and Winter (n = 115 & 540). Abbreviations: LPA, light physical activity; MPA, moderate physical activity; MVPA, moderate-to-vigorous physical activity; VPA, vigorous physical activity; TPA, total physical activity. * P < .05; ** P < .01; *** P < .001; † sig. different from summer with P < .05

Fig. 5

Histogram showing the distribution of the midpoint of the most active 10 h period during the day for patients with heart failure (HEART) and healthy individuals (HEALTH), respectively