Optimal aerobic exercise dose for improving metabolic health and functional outcomes in frail older adults: A systematic review and dose-response meta-analysis.

BACKGROUND AND AIMS: Aerobic exercise potentially mitigates frailty, yet its definitive efficacy and optimal prescription parameters remain unclear. This study aimed to quantify the efficacy and dose-response relationship of aerobic exercise on frailty and health outcomes.

METHODS

We conducted a systematic review and dose-response meta-analysis of randomized controlled trials involving adults ≥60 years with frailty or pre-frailty (searched through March 2026). Heterogeneous exercise protocols were standardized to metabolic equivalent (MET)-minutes/week. We employed random-effects models for efficacy, restricted cubic splines to model non-linear dose-response associations, and the GRADE framework to evaluate the certainty of evidence.

RESULTS

Forty-four studies (n = 4011) were included. Aerobic exercise significantly improved frailty status (Hedges' g = 0.34), depressive symptoms (Hedges' g = 0.37), muscle strength (Hedges' g = 0.21), cognitive function (Hedges' g = 0.67), quality of life (Hedges' g = 0.57), and lower-limb function (Hedges' g = 0.29 for TUGT; Hedges' g = 0.40 for 30CST) compared with usual care. Subgroup analyses showed consistent efficacy across modalities (e.g., Tai Chi, dance, walking) with no single superior type.

CONCLUSIONS

Available evidence suggests that aerobic exercise may improve frailty status and several functional and psychosocial outcomes in frail or pre-frail older adults. The dose-response findings support initiating achievable low-to-moderate volumes of aerobic exercise; however, between-study heterogeneity and sparse data at higher doses preclude firm conclusions regarding an optimal dose. Exercise prescriptions should therefore be individualized according to participants' tolerance, preferences, and clinical status.

REGISTRATION: PROSPERO CRD420251152761.