Evidence that women meeting physical activity guidelines do not sit less: An observational inclinometry study

Abstract

BackgroundThe inactivity physiology paradigm proposes that sedentary behaviors, including sitting too much, are independent of the type of physical activity delineated for health in the Physical Activity Guidelines for Americans. Thus, we hypothesized that, when accounting for behaviors across the entire day, variability in the amount of time spent sitting would be independent of the inter-and intra-individual time engaged in sustained moderate-to-vigorous physical activity (MVPA).MethodsNinety-one healthy women, aged 40–75 years, completed a demographic questionnaire and assessment of height and weight. Participants wore the activPAL activity monitor for one week and time (minutes/day) spent sitting, standing, stepping, and in sustained bouts (bouts ≥10 minutes) of MVPA were quantified. The women were then stratified into groups based on weekly sustained MVPA. Additionally, each day of data collection for each participant was classified as either a “sufficient” MVPA day (≥ 30 min of MVPA) or an “insufficient” MVPA day for within-participant analyses.ResultsTime spent sitting, standing, and in incidental non-exercise stepping averaged 64, 28, and 11 hrs/week, respectively, and did not differ between groups with individuals meeting/exceeding the current exercise recommendation of 150 min/week of sustained MVPA in ≥10 minutes bouts (M = 294 min/week, SD = 22) compared to those with none or minimal levels (M= 20min/week, SD = 4). Time spent sitting (M = 9.1 hr/day, SD = 0.19 vs. M = 8.8 hr/day, SD = 0.22), standing (M = 3.9 hr/day, SD = 0.16 vs. M = 3.9 hr/day, SD = 0.15), and in intermittent stepping (M = 1.6 hr/day, SD = 0.07 vs. M = 1.6 hr/day, SD = 0.06) did not differ between days with (~55 min/day) and without recommended MVPA.ConclusionsThis study provides the first objective evidence that participation in sustained MVPA is unrelated to daily sitting duration in relatively healthy, middle and older-aged women. More research is needed to extend these findings to other populations and to inform distinct behavioral recommendations focused on sedentary time.

Sedentary Behavior and Health-Related Quality of Life across Meeting Physical Activity Guidelines

“…Though meeting PAGs (i.e., engagement) was significantly associated to ST, it was not significantly associated to non-ST and more specifically total time sitting, which was consistent to previous research that found equivalent sitting-time between those meeting and not meeting PAGs [31]. On the other hand, given that ST was significantly associated with engagement, the position that the influence of sedentary behavior on health and health determinants varies based on the type of sedentary behavior was further supported [60].…”

“…Moreover, the consequences of sedentary behavior are thought to be independent of physical activity [21,27,28,29,30]. In fact, Craft and colleagues [31] indicated sedentary behavior (measured as time spent sitting) may not differ between individuals meeting and not meeting PAGs (aerobic), and Matthews and colleagues [30] revealed high levels of MVPA may not mitigate the health-risks associated with prolonged sitting, especially screen-time sitting. In addition, research indicates higher levels of sedentary behaviors are significantly associated with lower levels of HRQoL and reductions in sedentary behavior may significantly improve physical HRQoL [32,33].…”

“…That is, researchers have yet to investigate the sedentary behavior and its influence on HRQoL across individuals with varying physical activity engagement such as those not meeting either PAGs, those only meeting one of the PAGs, or those meeting both PAGs [29]. While research has suggested sedentary behavior may not differ between these groups and physical activity and sedentary behavior are independent determinants of health-outcomes [21,31], it is not known whether the negative impact of sedentary behavior on HRQoL varies between these groups. Given that the frequency of sedentary behavior is considered to be higher than previous decades [22,26] and individuals generally fall into one of these three groups, improving the understanding of the dose-response relations among these variables is crucial for developing interventions to enhance HRQoL [29].…”

Managing Sedentary Behavior to Reduce the Risk of Diabetes and Cardiovascular Disease

“…Research is also beginning to show that regardless of whether people are meeting public health physical activity recommendations (i.e. ≥150 minutes/week of MVPA), there are still adverse cardiometabolic consequences from exposure to prolonged bouts of sitting [7,15,[30][31][32][33]. These findings have added further corroboration to the argument that sedentary behaviours are a separate cluster of behaviours that may impose distinct cardiometabolic risks to that of physical inactivity.…”

“…Despite large-scale physical activity intervention approaches and policy changes being put in place, physical activity continues to be rejected or ignored by large numbers [4,18]. Second, growing numbers of people are spending disproportionate amounts of their time in prolonged and unbroken periods of sedentary behaviour [15,33,74], which appear to have deleterious health consequences even among those meeting physical activity recommendations [31,32].…”