Associations between Total Daily Step Count and Minutes of “Healthy” Physical Activity

Total daily step count recommendations for healthy physical activity have recently increased in popularity. Few studies have addressed whether total activity (steps per day) is related to daily minutes of healthy physical activity that would correspond to current health-related recommendations for moderate-to-vigorous intensity physical activity (MVPA) (Pate, 1995). PURPOSE: To examine the relationship between total daily steps and minutes of MVPA, across multiple METHODS of measurement and multiple populations. METHODS: Pedometer and accelerometer measures of daily physical activity were obtained from samples of young (Y; n = 51), middle aged (MA; n = 107), and older (O; n = 50) adults during their regular physical activity. Data were also collected from a middle-aged to older adult sample (MAO; n = 57) who were enrolled in an organized walking program. Participants wore Omron pedometers (Y, MAO samples), Yamax pedometers (Y, MA, O samples), and/or Actigraph accelerometers (Y, MA, O samples) for 24 h. Total daily steps were obtained from all three instruments. Minutes of MVPA were obtained in three ways: (a) using the Omron “aerobic steps” mode, which saves steps above 60 steps/min if accumulated in bouts of at least 10 min; (b) from Actigraph counts using the Freedson et al (1998) cut-offs for moderate activity (≥ 1952 cts/min) over all minutes (intermittent MVPA); and (c) from Actigraph counts ≥ 1952 cts/min accumulated in bouts of at least 10 min. RESULTS: The correlations between Omron total steps and Omron-determined minutes of aerobic steps were r = .68 (MAO sample) and r = .71 (Y sample). Correlations between total steps and Actigraph-determined intermittent MVPA minutes ranged from r = .18 (Actigraph steps, Y sample) to r = .84 (Omron steps, Y sample); mean r = .59. For Actigraph-determined MVPA in 10+ min bouts, correlations ranged from r = .14 (Actigraph steps, Y sample) to r = .70 (Yamax steps, O sample); mean r = .46. CONCLUSIONS: Using two different criteria for healthy physical activity, the association between total steps and minutes of MVPA across several samples and measurement METHODS ranged from very low (2% common variance) to high (70% common variance), with an average 31 % common variance between the two forms of expressing “healthy” physical activity behavior.