The Association of Physical Activity Fragmentation with Physical Function in Older Adults: Analysis from the SITLESS Study

Jochen Klenk,Nicole E Blackburn,Paolo Caserotti,Emma Mcintosh,Natalie Klempel,Jason J Wilson,Javier Jerez-Roig,Ilona Mcmullan,Guillermo R Oviedo,Mathias Skjødt,Dhayana Dallmeier,Laura Coll-Planas,Mark A Tully

doi:10.3390/jal2010006

Abstract

The distribution of physical activity bouts through the day may provide useful information for assessing the impacts of interventions on aspects such as physical function. This study aimed to investigate the associations between physical activity fragmentation, tested using different minimum physical activity bout lengths, with physical function in older adults. The SITLESS project recruited 1360 community-dwelling participants from four European countries (≥65 years old). Physical activity fragmentation was represented as the active-to-sedentary transition probability (ASTP), the reciprocal of the average physical activity bout duration measured using ActiGraph wGT3X+ accelerometers. Four minimum bout lengths were utilised to calculate the ASTP: ≥10-s, ≥60-s, ≥120-s and ≥300-s. Physical function was assessed using the 2-min walk test (2MWT) and the composite score from the Short Physical Performance Battery (SPPB) test. Linear regression analyses, after adjusting for relevant covariates, were used to assess cross-sectional associations. After adjustment for relevant covariates, lower ASTP using ≥10-s bouts were associated with longer 2MWT distances and higher SPPB scores. Lower ASTP using ≥120-s bouts and ≥300-s bouts were associated with longer 2MWT distances but not the SPPB. Less fragmented physical activity patterns appeared to be associated with better physical function in community-dwelling older adults.

Highlights

In ageing populations, sufficient levels of physical activity at any intensity have been shown to reduce premature mortality, improve both physical and psychological function by reducing chronic disease risk and generally lead to better health and wellbeing [1–4]
This study investigated associations between physical activity fragmentation, calculated using different minimum bout lengths, with physical function in community-dwelling older adults
2-min walk test (2MWT) distances, no significant associations were found for active-to-sedentary transition probability (ASTP) using ≥60-s physical activity bouts. These findings suggest that more fragmented physical activity patterns, with reduced longer bout patterns, may be an indirect indicator of reduced functional capacity in older adults

Summary

Introduction

Sufficient levels of physical activity at any intensity have been shown to reduce premature mortality, improve both physical and psychological function by reducing chronic disease risk and generally lead to better health and wellbeing [1–4]. Current guidelines recommend that older adults should be achieving ≥150 min of moderate physical activity, ≥75 min of vigorous physical activity or a combination of both every week while limiting prolonged sedentary behaviour [8–10]. Evidence in older men has shown similar reduced risks of cardiovascular disease events from accumulating 150 min/week moderate-vigorous physical activity sporadically or in continuous bouts of greater than 10 min [11]. These new guidelines are more likely to be sustainable for individuals who are frailer and less physically fit. It has been suggested that a more fragmented physical activity pattern containing few sustained physical activity bouts coupled with frequent sedentary breaks may suggest higher levels of frailty and fatigability due to reduced muscle function [12,13]

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