Effects and social design features of physical activity interventions on loneliness and subjective well-being in older adults: a systematic review

Physical activity is promoted in later life, yet its capacity to reduce loneliness or improve subjective well-being remains uncertain when social contact is incidental rather than intentionally designed. This review synthesised controlled intervention evidence and examined how social-design features were classified across interventions. Following PRISMA 2020, Web of Science Core Collection, PubMed and CENTRAL were searched for controlled studies published during 2022–2026. Eligible studies involved adults aged 60 years or older and measured loneliness, evaluative subjective well-being, particularly life satisfaction, subjective happiness, positive affect or negative affect. Twenty-four studies were included and synthesised narratively. Findings were heterogeneous across comparator types, outcome measures and risk-of-bias profiles. Some interventions reported favourable loneliness or affective outcomes, particularly movement-based, neighbourhood-oriented or multicomponent programmes, but evidence for evaluative subjective well-being, particularly life satisfaction, was weaker and less consistent. Social-design features were unevenly specified and rarely tested as mechanisms. Group or digital delivery without explicit relational content did not provide reliable evidence of social benefit. Analyses of delivery mode, participant context, sex, gender and equity-related factors were limited. The evidence remains insufficient to determine whether physical activity interventions, specific social-design features or delivery modes reliably reduce loneliness or improve subjective well-being. Future studies should separate physical and relational objectives, test social mechanisms directly and evaluate effects across diverse populations and settings.