The impact of physical activity on chronic diseases: a meta-analysis

Chronic diseases represent a major global health challenge. While physical activity is advocated for prevention and management, the comparative efficacy of different exercise modalities and the influence of geographic context remain areas requiring definitive synthesis. This meta-analysis aimed to: (1) quantify the pooled effect of physical activity on key health indicators in people with, or at risk of, chronic disease; (2) compare the effectiveness of different exercise types; and (3) examine regional variation in outcomes. We conducted a systematic review and meta-analysis following PRISMA guidelines. Four electronic databases (PubMed, Google Scholar, Web of Science, and Embase) were searched from inception to December 2023, yielding 2,867 initial records. After screening, 93 effect sizes from 48 publications were included. All outcomes were continuous, and a single effect measure was used throughout: the standardized mean difference expressed as Hedges’s g, pooled with 95% confidence intervals (CIs) under a random-effects model estimated by restricted maximum likelihood (REML). Heterogeneity was quantified using Cochran’s Q, the I² statistic and τ². Subgroup analyses were performed for exercise modality, health indicator, geographic region and disease type, and differences between subgroups were tested using the Q statistic for between-group heterogeneity (Qb). The review was registered on PROSPERO (CRD420261357663). Across all 93 effect sizes the pooled estimate favoured physical activity (g = -0.68, 95% CI: -1.02 to -0.34; I² = 98.70%); because this overall value aggregates indicators whose desirable direction differs, the indicator-specific estimates below are the more informative results. Among exercise modalities, only aerobic exercise reached statistical significance (g = -0.54, 95% CI: -0.82 to -0.27); resistance exercise (g = -0.45, 95% CI: -1.96 to 1.06) and combined aerobic-plus-resistance exercise (g = -1.27, 95% CI: -2.64 to 0.09) had confidence intervals that included zero, and the three modalities did not differ significantly from one another (Qb(2) = 1.08, p = 0.58). Physical activity significantly improved systolic blood pressure (g = -1.26, 95% CI: -2.11 to -0.42), diastolic blood pressure (g = -0.99, 95% CI: -1.85 to -0.13), heart rate (g = -1.01, 95% CI: -1.73 to -0.30) and VO2max (g = 1.17, 95% CI: 0.18 to 2.17; for this outcome a positive value denotes improvement), but had no significant effect on BMI (g = -0.42, 95% CI: -0.88 to 0.04), physical health (g = -0.38, 95% CI: -1.14 to 0.38) or mental health (g = 0.06, 95% CI: -0.44 to 0.57). Total cholesterol was the only indicator to move significantly in an unfavourable direction (g = 2.95, 95% CI: 2.36 to 3.53), an estimate resting on a single effect size. Effects were significant for hypertension (g = -0.90, 95% CI: -1.43 to -0.37) and diabetes (g = -0.57, 95% CI: -1.07 to -0.07) but not for cardiovascular disease (g = -0.17, 95% CI: -0.39 to 0.04). The largest regional point estimate was observed in Asia (g = -1.19, 95% CI: -1.96 to -0.41), followed by North America and Europe among the regions reaching significance, although between-region differences were not statistically significant (Qb(5) = 8.32, p = 0.14). This meta-analysis indicates that physical activity improves several key health indicators in people with chronic disease, with the clearest benefits for blood pressure, heart rate and cardiorespiratory fitness, and for hypertension and diabetes specifically; no significant effect was found for body mass index, physical health, mental health, or for cardiovascular disease. Aerobic exercise was the only modality with a statistically significant pooled effect, but because the modalities did not differ significantly from one another, the superiority of any single modality cannot be established from these data, and the same applies to the regional comparison. Given the very high heterogeneity, these pooled estimates should be interpreted with caution. The findings nonetheless reinforce the importance of promoting physical activity and support the development of tailored, region-sensitive public health strategies alongside better-standardized primary trials in underrepresented regions.