How Many Steps Are Enough? Dose–Response Curves for Pedometer Steps and Multiple Health Markers in a Community-Based Sample of Older Australians

BACKGROUND: Although an overall public health target of 10,000 steps per day has been advocated, the dose-response relationship for each health benefit of physical activity may differ. METHODS: A representative community sample of 2458 Australian residents aged 55-85 wore a pedometer for a week in 2005-2007 and completed a health assessment. Age-standardized steps per day were compared with multiple markers of health using locally weighted regression to produce smoothed dose-response curves and then to select the steps per day matching 60% or 80% of the range in each health marker. RESULTS: There is a linear relationship between activity level and markers of inflammation throughout the range of steps per day; this is also true for BMI in women and high density lipoprotein in men. For other markers, including waist:hip ratio, fasting glucose, depression, and SF-36 scores, the benefit of physical activity is mostly in the lower half of the distribution. CONCLUSIONS: Older adults have no plateau in the curve for some health outcomes, even beyond 12,000 steps per day. For other markers, however, there is a threshold effect, indicating that most of the benefit is achieved by 8000 steps per day, supporting this as a suitable public health target for older adults.