High-intensity interval training improves cardiorespiratory fitness in cancer patients and survivors: A meta-analysis.

Objective: The primary objective of this systematic review and meta-analysis was to compare the effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) and usual care (UC) on cardiorespiratory fitness (peak V̇O ) in cancer patients and survivors. Secondary objectives were to compare the effects of HIIT versus MICT and UC on other cardiopulmonary exercise testing (CPET) indices. Safety and adherence to HIIT were also evaluated.

Methods: A systematic review and meta-analysis of controlled trials were undertaken using eligible studies from electronic database searching (inception-December 2019). Mean differences (MD) with 95% confidence intervals (CI) were compared and heterogeneity assessed using Cochran's Q and I statistic.

Results: Twelve eligible studies included 516 participants with post-intervention CPET data. No serious adverse events occurred. Adherence to HIIT ranged between 71.2% and 95.6%. HIIT had significantly higher peak V̇O compared with UC (MD = 2.11 ml kg  min , 95% CI 0.75-3.47, p = .002). No significant difference was found between HIIT and MICT (MD = 2.03 ml kg  min , 95%CI -0.75-4.83, p = .15). HIIT was more effective than UC to improve peak oxygen pulse (MD = 1.59 ml/beat, 95%CI 0.06-3.12, p = .04).

Conclusions: Quantitative assessment of HIIT studies indicates good compliance, with a significant effect on peak V̇O and peak oxygen pulse compared with UC in cancer patients and survivors. HIIT demonstrates a comparable effect with MICT to improve peak V̇O .