Urological malignancies are common, with surgery resulting in high complication rates and reduced quality of life for survivors. Improving cardiorespiratory fitness (CRF) before surgery may improve outcomes. Cardiopulmonary exercise testing (CPET) identifies patients at risk of post-operative complications, and increasing anaerobic threshold (VO2AT) by 1.5–2.0 ml/kg/min is considered a minimally clinically important difference (MCID). Prehabilitation exercise aims to increase physiological reserve before surgery. However, most urology prehabilitation studies focus on specific complications, not general physiological parameters. The National Cancer Action Team's 31-day treatment target limits the time for prehabilitation interventions. Moderate continuous training (MCT) is commonly used to improve CRF but takes too long for pre-operative use. High-intensity interval training (HIIT) offers a time-efficient alternative, proven effective in improving CRF in shorter time periods than MCT. This study aimed to determine if patients with urological malignancy could achieve the MCID in CRF with HIIT within 31 days, along with the effects on blood pressure, body composition, muscle architecture, and patient acceptability.

The introduction section extensively reviews the literature on urological cancer surgery, post-operative complications, the importance of CRF, CPET, minimally clinically important differences (MCIDs) in VO2AT, and the benefits of prehabilitation exercise. It highlights the limitations of existing prehabilitation approaches in urology and the rationale for using HIIT as a time-efficient intervention to improve CRF before surgery within the constraints of the UK's 31-day cancer treatment target.

This parallel-group randomized controlled trial (RCT) recruited patients scheduled for major urological surgery. Patients aged >65 years were randomized (1:1) to either a four-week, fully supervised HIIT intervention or standard care. The primary outcome was change in VO2AT. Secondary outcomes included changes in blood pressure, body composition, muscle architecture (measured by ultrasound), and patient-reported outcomes (Dukes Activity Status Index, EQ-5D-5L, WEMWBS). The HIIT protocol involved 5 × 1-min exertions at 100–115% of maximal wattage achieved during baseline CPET, interspersed with 1-min rest periods. CPET was performed before and after the intervention. Data were analyzed using ANCOVA, with baseline values as covariates. Intention-to-treat analysis was performed.

Forty patients were randomized (34 completed). Intention-to-treat analysis showed a significant improvement in VO2AT (mean difference 2.26 ml/kg/min, 95% CI 1.25–3.26) and VO2PEAK (mean difference 2.16 ml/kg/min, 95% CI 0.24–4.08) following HIIT. There was also a significant increase in CPET wattage at failure (mean difference 12.86 W, 95% CI 5.52–20.19). Systolic blood pressure decreased significantly (−8.2 mmHg, 95% CI −16.09 to −0.29), as did diastolic blood pressure (−6.47 mmHg, 95% CI −12.56 to −0.38). Muscle thickness and pennation angle increased significantly in the HIIT group. There were no significant changes in body composition parameters. No adverse safety events were reported. Patient adherence to the HIIT protocol was 84%, and patients reported the intervention to be enjoyable and acceptable.

This study demonstrates that HIIT can significantly improve CRF and cardiovascular health in patients awaiting urological surgery within the 31-day timeframe mandated by the UK National Cancer Action Team. The observed improvements in VO2AT exceeded the MCID. The reduction in blood pressure is also clinically significant. The HIIT protocol was well-tolerated and acceptable to patients. The findings support the implementation of HIIT as a feasible and effective prehabilitation strategy for urological cancer patients. The use of supervised, laboratory-based HIIT may limit generalizability, however, as it is resource-intensive.

This study provides strong evidence for the efficacy and feasibility of HIIT as a prehabilitation intervention for urological cancer patients. The significant improvements in CRF and cardiovascular health within a short timeframe are clinically relevant. Future research should investigate the impact of HIIT on post-operative complications, long-term survival, and cost-effectiveness, as well as explore the application of HIIT in other cancer types and the feasibility of delivering less resource-intensive HIIT programs.

The study was relatively small and focused primarily on prostate cancer patients. The supervised, laboratory-based setting of the HIIT intervention may limit the generalizability of the findings to real-world settings. Future research should investigate the effectiveness of less resource-intensive HIIT programs that can be delivered in community or home settings. Furthermore, the study lacked a longer follow-up period to assess the long-term effects of HIIT on post-operative outcomes.