Physical Activity and Components of Fitness
- Lower sedentary time (SED), and greater steps/day and moderate–vigorous physical activity (MVPA) (and their changes over time) were each associated with better cardiorespiratory fitness measures.
- The highest effect estimate was observed for MVPA, which was associated with favorable cardiopulmonary exercise testing fitness measures throughout various intensity levels of incremental exercise (i.e., from initiation to recovery).
- Different forms of PA (especially MVPA) are associated with cardiorespiratory fitness in the general public regardless of one’s age, sex, BMI, or CVD status and should be universally encouraged.
What are the direct links between distinct components of physical activity (PA), their changes over time, and cardiorespiratory fitness?
The investigators obtained and analyzed maximum effort cardiopulmonary exercise testing (CPET) and objective PA measures (sedentary time [SED], steps/day, and moderate–vigorous PA [MVPA]) via accelerometers worn for 1 week concurrent with CPET and 7.8 years prior were obtained in 2,070 Framingham Heart Study participants. The authors evaluated the cross-sectional associations of CPET (dependent) variables with PA measures at exam 3 (independent variables) using multivariable linear regression models adjusted for age, sex, cohort, season of activity monitor wear (fall: September–November; winter: December–February; spring: March–May; summer: June–August), location (New England vs. others, to account for geographic weather differences that may affect PA), average minutes of activity monitor wear (for steps and MVPA), body mass index (BMI), resting systolic blood pressure, hypertension medication use, smoking, diabetes, and prevalent cardiovascular disease (CVD).
Study participants were aged 54 ± 9 years, 51% women, SED 810 ± 83 min/day, steps/day 7,737 ± 3,520, MVPA 22.3 ± 20.3 min/day, and peak oxygen uptake (VO2) was 23.6 ± 6.9 ml/kg/min. Adjusted for clinical risk factors, increases in steps/day and MVPA and reduced SED between the two assessments were associated with distinct aspects of cardiorespiratory fitness (measured by VO2) during initiation, early–moderate level, peak exercise, and recovery, with the highest effect estimates for MVPA (false discovery rate <5% for all). Findings were largely consistent across categories of age, sex, obesity, and cardiovascular risk. Increases of 17 minutes of MVPA/day (95% confidence interval [CI], 14-21) or 4,312 steps/day (95% CI, 3,439-5,781; ~54 minutes at 80 steps/min), or reductions of 249 minutes of SED per day (95% CI, 149-777) between the two exam cycles corresponded to a 5% (1.2 ml/kg/min) higher peak VO2. Individuals with high (above-mean) steps or MVPA demonstrated above average peak VO2 values regardless of whether they had high or low SED.
The authors concluded these data suggest that favorable longitudinal changes in PA (and MVPA in particular) are associated with greater objective fitness.
This study reports that lower SED, and greater steps/day and MVPA (and their changes over time) were each associated with better cardiorespiratory fitness measures. Furthermore, the highest effect estimate was observed for MVPA, which was associated with favorable CPET fitness measures throughout various intensity levels of incremental exercise (i.e., from initiation to recovery). These findings suggest that different forms of PA (especially MVPA) are associated with cardiorespiratory fitness in the general public regardless of one’s age, sex, BMI, or CVD status and should be encouraged.
Keywords: Accelerometry, Blood Pressure, Body Mass Index, Cardiorespiratory Fitness, Diabetes Mellitus, Exercise, Exercise Test, Fitness Trackers, Hypertension, Metabolic Syndrome, Obesity, Primary Prevention, Risk Factors, Sedentary Behavior, Smoking
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