S25 / Fitness and wellness
Daily activity patterns and the limits of wellness segmentation
A wellness analytics team wants to understand whether daily activity rhythms reveal useful population segments beyond total movement. Study how pattern estimates change with wear-time quality and demographic composition.
Planned topic
Proposed design & source
Functional PCA; clustering stability; complex survey inference
Build participant-level daily curves from NHANES monitor summaries using documented MIMS units, wear/sleep flags and quality checks. Fit functional principal components and a small, stable clustering model. Link same-cycle public demographics and selected examination/laboratory measures by participant ID only as explicitly documented companion files.
Evaluation: Compare rhythm-based segments against total-activity bins. Assess within-person day-to-day reliability, weighted cluster stability and sensitivity to valid-day thresholds. Hold participants together and test transfer between survey cycles; report weighted uncertainty and sample exclusions.
Boundary: Use thresholds appropriate to MIMS, not legacy accelerometer-count cutoffs. These data do not measure gym retention or validate personalized wellness advice; linked health endpoints require compatible survey weights and eligibility.