Purpose
To catalog the relationships between step-based accelerometer metrics indicative of physical activity volume (steps/day, adjusted to a pedometer scale), intensity (mean steps/min from the highest, not necessarily consecutive, minutes in a day; peak 30-min cadence) and sedentary behavior (percent time at zero cadence relative to wear time; %TZC) and cardiometabolic risk factors.
Methods
We analyzed data from 3388 20+ year-old participants in the 2005-2006 National Health and Nutrition Examination Survey with ≥1 valid day of accelerometer data and at least some data on weight, BMI, waist circumference, systolic and diastolic blood pressure, glucose, insulin, HDL-cholesterol, triglycerides, and/or glycohemoglobin. Linear trends were evaluated for cardiometabolic variables, adjusted for age and race, across quintiles of steps/day, peak 30 min-cadence, and %TZC.
Results
Median steps/day ranged from 2247-12334 for men and 1755-9824 steps/day for women, and median peak 30-min cadence ranged from 48.1-96.0 for men and 40.8-96.2 steps/min for women, for the 1st and 5th quintiles, respectively. Linear trends were statistically significant (all p<0.001), with increasing quintiles of steps/day and peak 30-min cadence inversely associated with waist-circumference, weight, BMI and insulin, for both men and women. Median %TZC ranged from 17.6-51.0% for men and 19.9-47.6% for women, for the 1st and 5th quintiles, respectively. Linear trends were statistically significant (all p<0.05), with increasing quintiles of %TZC associated with increased waist circumference, weight and insulin for men, and insulin for women.
Conclusions
This analysis identified strong linear relationships between step-based movement/non-movement dimensions and cardiometabolic risk factors. These data offer a set of quantified access points for studying the potential dose-response effects of each of these dimensions separately or collectively in longitudinal observational or intervention study designs.
