Device-Based Measures of Sedentary Time and Physical Activity Are Associated With Physical Fitness and Body Fat Content

Abstract

Introduction/Purpose: Physical activity and sedentary time may associate with physical fitness and body composition. Yet, there exists some observational studies that have investigated the associations of device-based measures of sedentary time and physical activity (PA) with cardiorespiratory fitness (CRF) and body composition but associations with muscular fitness (MF) are less studied.Methods: Objective sedentary time and physical activity was measured by a hip worn accelerometer from 415 young adult men (age: mean 26, standard deviation 7 years). Cardiorespiratory fitness (VO2max) (CRF) was determined using a graded cycle ergometer test until exhaustion. Maximal force of lower extremities was measured isometrically and lower body power was assessed using standing long jump (MF). Body composition was determined with bioimpedance method. Single and compositional approach was used in regression analysis.Results: Mean sedentary time was 707 (standard deviation 133) minutes per day (77 ± 8% of the wear time). Volumes of all PA intensities were positively associated with CRF and associations showed linearly increasing magnitudes with higher intensities in single regression models adjusted for age and smoking (p < 0.001). Similarly, PA intensities were positively associated with lower body MF, however, with weaker associations (p < 0.005). After further adjustment for resistance training, the associations remained significant. The associations of the relative distribution of time within sedentary behavior (SB), light intensity PA (LPA) and moderate-to-vigorous PA (MVPA) behaviors as a whole with using compositional analysis further revealed that within the composition MVPA and SB were positively associated with CRF and MF (p < 0.001), while LPA was not. In addition, within the composition, accumulated PA bouts lasting more than 3 min were consistently associated with CRF and MF, and with all body composition variables (p < 0.001), while sedentary time was associated with body fat percentage (p < 0.001).Conclusion: Promoting physical activity and reducing sedentary time may have positive influence on physical fitness and body fat content, and thereby may offer positive health effects. Physical activity of higher intensities may offer greater benefits.

Aerobic Capacity Determines Habitual Walking Acceleration, Not Electromyography-Indicated Relative Effort

“…In previous studies, accelerometry-measured absolute total physical activity level has been higher in men than women, decreased by BMI, and increased by aerobic fitness level (Dyrstad et al, 2016;Kujala et al, 2017;Tucker et al, 2011;Vaara et al, 2020). Such estimations of absolute physical activity can lead to underestimated physical activity in those with a lower aerobic fitness level.…”

“…However, accelerometer-measured physical activity intensity lacks consideration for an individual's fitness level. People with a high aerobic fitness level have more moderate and vigorous physical activity and are more likely to meet the current physical activity guidelines defined as 150 min/week of moderate to vigorous physical activity when estimated with accelerometry (Dyrstad et al, 2016;Vaara et al, 2020). When the activity volume is considered relative to maximal fitness, people with high and low aerobic fitness levels have a more similar activity profile (Kujala et al, 2017).…”

Blood and affective markers of stress in Elite Airmen during a preparatory training course: A pilot study

“…They have both relevance and significance as characteristics of trainee's ability to deal with and recover from the physical component of the stress. Furthermore, exhaustive physical activity, which in this study occurred at the extended training days of D20* and D42*, is known to effect affective state ( Henning et al 2011 ; Vaara et al, 2020 ; Lieberman et al, 2016 ). Levels of Cl, an electrolyte found in blood, were significantly higher in non-grads at both D1 and at D52 compared to that in grads.…”

“…Both animal and human studies have identified strain or individual differences in reactivity to stress, whether physical or emotional ( Solberg et al, 2006 ; Mann et al 2014 ). Since stress affects both physiological and affective processes ( Henning et al 2011 ; Vaara et al, 2020 ; Lieberman et al, 2016 ), the ideal measures of stress reactivity would contain some of these factors. The most well-known physiological stress response is the activation of the hypothalamic-pituitary-adrenal (HPA) axis.…”

Sedentary Behaviors and Health Outcomes among Young Adults: A Systematic Review of Longitudinal Studies

“…To strengthen the evidence based on sedentary behavior as an adult health risk, a large number of longitudinal studies have been conducted to investigate the association between sedentary behavior and health outcomes among adults, but the findings have been mixed [ 9 , 10 , 11 , 12 , 13 ]. Some studies have reported that sedentary behavior is associated with health outcomes.…”