The effectiveness of nudge-based physical activity interventions in frail older adults: a systematic review.

Background: Frailty is a prevalent geriatric syndrome in older adults, characterized by reduced physiological reserves and increased vulnerability to adverse health outcomes. Physical inactivity is a key modifiable risk factor that accelerates frailty progression. Nudge-based interventions, which subtly guide behavior through choice architecture, offer a promising, low-cost approach to promoting physical activity and improving health outcomes in this population METHODS: A systematic search was conducted in PubMed, EMBASE, Cochrane Library, Web of Science, PsycINFO, and EconLit from inception to May 20, 2025, for randomized controlled trials (RCTs) on nudge-based physical activity interventions in frail older adults. Two reviewers independently performed study selection, data extraction, and quality assessment using the Cochrane risk-of-bias tool. Pooled effect sizes were calculated using random- or fixed-effects models as appropriate, with standardized mean difference (SMD) or mean difference (MD) reported for continuous outcomes. Statistical heterogeneity was assessed using I² and Cochran's Q tests.

Results: A total of 16 studies involving 2,730 participants were included. Meta-analysis indicated that physical activity interventions based on nudge strategies significantly improved depressive symptoms [SMD = - 0.30, 95% CI (- 0.51, - 0.09), P = 0.016], enhanced cognitive function [SMD = 0.47, 95% CI (0.26, 0.69), P = 0.005], increased physical activity levels [SMD = 1.09, 95% CI (0.43, 1.75), P = 0.001], improved gait speed [MD = 0.07, 95% CI (0.03, 0.11), P = 0.001], enhanced quality of life (QoL) [SMD = 1.02, 95% CI (0.09, 1.94), P = 0.031], and reduced frailty scores [SMD = - 2.00, 95% CI (- 3.01, - 1.00), P < 0.001]. Although improvements were observed in self-efficacy, grip strength, balance ability, and Timed Up and Go (TUG) test performance, these differences were not statistically significant (P > 0.05).

Conclusions: Physical activity interventions based on nudge strategies can significantly increase physical activity levels, effectively improve frailty status, depressive symptoms, cognitive function, gait speed, and QoL among frail older adults. These interventions represent a low-cost and highly feasible behavioral approach for promoting healthy aging.

Registration: CRD420251229406.