Cardiorespiratory and Metabolic Responses After Sleeve Gastrectomy in Adults With Obesity: Systematic Review.

Following sleeve gastrectomy (SG), relative VO₂peak improves, yet absolute VO₂peak declines at all reported time points, revealing a paradoxical dissociation between apparent and actual aerobic capacity. This systematic review synthesizes very limited evidence from seven observational reports (n = 162, two independent cohorts) identified through PubMed, Scopus, CENTRAL, and ProQuest (2015-2025), restricted to studies using cardiopulmonary exercise testing with direct gas analysis. Oxygen uptake kinetics (τ) worsened at 1 and 6 months before trending toward baseline by 16 months. Walking economy improved through biomechanical adaptations. These findings are consistent with a possible period of metabolic vulnerability in the early post-SG months, during which tolerance to high-intensity exercise may be reduced. However, this hypothesis requires prospective validation.