Nine years of mailed nudges got older women moving. A little.
People say: “Can reminders keep older women active for years?” We read the study.
Randomised controlled trial (RCT). 49,331 people. median 8.7 years of follow-up (intervention ran ~9 years, 2015-2024).
A trial. Chance decided who did what.
Who: US women aged 66-99 (mean 79.7) from the Women's Health Initiative Extension Study 2; excluded known dementia, nursing-home residents, self-reported inability to walk, Spanish-language preference; 86.8% White, 8.8% Black; mean BMI 28
- Walking+3.2%self-reported
- Sitting-1.5%~45 min less/week
- Total exercise+3.7%~14 min walk/week
More to know, from our read of the paper:
- All activity and sitting outcomes are self-reported (annual questionnaires); intervention participants were not blinded (authors' main weakness)
- Effects are very small: e.g. walking +0.11 MET-hr/wk, total exercise +0.58 MET-hr/wk (~14 min/week of slow walking per the authors), sitting -0.76 h/week. Authors: improvements were 'dwarfed' by the age-related decline in both groups
- Health outcomes (the trial's primary outcome is major CVD events) are NOT in this paper; whether the changes bring health benefits is still being studied. Never claim health effects
- Randomized consent design: the comparison group was not told they were in the trial; 4.1% of the intervention arm opted out of materials but stay in the intention-to-treat analysis
- Minor inconsistency: passive consent given as 95.9% in the abstract and 95.6% in Methods (23,653 of 24,657 = 95.9%)
A small help. The age decline was far bigger.
This randomized trial split 49,331 US women aged 66 to 99 into two groups. One got about nine years of mailed newsletters, exercise tips, a step counter and monthly phone messages; the other got nothing new. The nudged women reported about 3% more walking, 3.7% more total exercise (roughly 14 minutes of slow walking a week) and 1.5% less sitting (about 45 minutes a week). Activity was self-reported, and it fell with age in both groups. The nudges slowed that only a little.
Stefanick ML, Mackey SF, Larson JC, Tinker LF, McGuire V, Rovzar CM, Oppezzo M, LaMonte MJ, Kooperberg C, LaCroix AZ, King AC (2026). Physical activity and sitting over 9 years of the Women's Health Initiative Strong & Healthy (WHISH) randomized physical activity intervention trial in older women. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences.
Design: Randomised controlled trial (RCT) · pragmatic randomized controlled trial with a randomized consent (Zelen) design; intention-to-treat comparison; remotely delivered 'light touch' physical activity intervention vs usual activity; all activity outcomes self-reported; participants not blinded (NCT02425345)
Goals:
We read the abstract and the full text of this paper and checked every number on this page against it (17 facts, checked on 2026-10-29). The study design is named above. Cohort and other observational studies are described as linked, not proven. Found an error? Email theis@onestudyaday.com.
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