High-Intensity Interval Training During Cancer Prehabilitation May Improve Cardiorespiratory Fitness: A Meta-Analysis

Background/Objectives: Cardiovascular disease is the leading cause of non-cancer mortality in cancer survivors. Exercise interventions are widely used to enhance cardiorespiratory fitness, typically assessed by VO₂peak, which predicts postoperative complications and poorer clinical outcomes. Prehabilitation provides an opportunity to optimize health. Given time constraints, high-intensity interval training (HIIT) may represent a time-efficient strategy to improve fitness during prehabilitation. This meta-analysis examines the effects of HIIT-based prehabilitation versus usual care on VO₂peak in cancer patients. Methods: A systematic search was conducted in Cinahl, Embase, PubMed, Scopus, and Web of Science from database inception to August 1, 2024 using terms related to cancer, prehabilitation, and HIIT. Random-effects meta-analysis was performed on studies assessing the effects of HIIT versus usual care on VO₂peak in adults with cancer undergoing prehabilitation. Seven studies comprising 352 participants (aged 56-73 years) with mixed cancer types were analyzed. Methodological quality was assessed using the Cochrane Risk of Bias tool (v2) and the Consensus on Exercise Reporting Template (CERT). The primary outcome was VO₂peak, analyzed using standardized mean differences (SMD) with 95% confidence intervals (CI). Results: The meta-analysis demonstrated a small but statistically significant effect in favor of HIIT over UC (SMD = 0.31, 95% CI = 0.09-0.52, p < 0.01), with low between-study heterogeneity (I² = 10%). Conclusions: This meta-analysis shows that HIIT-based prehabilitation can improve cardiorespiratory fitness in cancer patients and may provide a clinically relevant, time-efficient strategy to optimize functional capacity before treatment. However, the included studies exhibited substantial clinical heterogeneity, and although all interventions were labeled as HIIT, exercise intensity was not assessed consistently across studies, underscoring the need for cancer-specific randomized controlled trials with standardized HIIT protocols and objective intensity verification.