J Affect Disord. 2026 Sep 6:122480. doi: 10.1016/j.jad.2026.122480. Online ahead of print.
ABSTRACT
BACKGROUND: Cardiorespiratory fitness (CRF) predicts cardiovascular and all-cause mortality and is reduced in severe mental illness. This systematic review with meta-analysis estimated the mean CRF of people with bipolar disorder (BD), the difference from controls without BD, and the effect of physical activity interventions on CRF in BD.
METHODS: Five databases (PubMed, Embase, Web of Science, PsycINFO, SPORTDiscus) were searched from inception to November 24, 2025, and updated on August 25, 2026. Random-effects models pooled the mean CRF and the difference versus controls; subgroup and sensitivity analyses were post hoc. The review was not prospectively registered.
RESULTS: Twenty studies were included; ten reported oxygen uptake, nine of which were pooled. In adults, mean CRF was 27.0 mL/kg/min (k = 8, n = 190; 95%CI 21.5 to 32.5; I2 = 97.0%); adding the adolescent sample gave 28.7 mL/kg/min (k = 9, n = 210; 95%CI 22.3 to 35.1; I2 = 98.1%). CRF was 7.4 mL/kg/min lower in BD than in controls (k = 7, n = 333; 95%CI -12.7 to -2.1; p = 0.006; I2 = 89.9%; standardized mean difference – 0.89, 95%CI -1.41 to -0.38). Only two uncontrolled pilot studies reported pre-post CRF, precluding meta-analysis.
LIMITATIONS: The evidence base is small, cross-sectional and heterogeneous; the between-group estimate was not robust to excluding one study, and two indirect protocols applied to the same participants differed by 19.3 mL/kg/min.
CONCLUSION: CRF was consistently lower in BD than in healthy controls, although heterogeneity means the pooled mean is a descriptive summary rather than a representative value. No conclusion about exercise efficacy can be drawn. Adequately powered controlled trials with standardized CRF assessment are required.
PMID:42702273 | DOI:10.1016/j.jad.2026.122480
