High-intensity interval training effects in cardiorespiratory fitness of lung cancer survivors: a systematic review and meta-analysis

Purpose: To assess the exercise intervention focused on high-intensity interval training (HIIT) in lung cancer survivors. Design: We performed a literature search using PubMed, Web of Science, and Science Direct (last search March 2021). Quality assessment and risk of bias were assessed using the Downs and Black scale and the Cochrane tool. Participants: A total of 305 patients of 8 studies were assessed, with their mean age ranging from 61 +/- 6.3 to 66 +/- 10 years in the exercise group and from 58.5 +/- 8.2 to 68 +/- 9 years in the control group. Methods: A systematic review and meta-analysis of randomized controlled trials and pilot randomized controlled trials was performed. We included controlled trials testing the effect of HIIT in lung cancer survivors versus the usual care provided to these patients. The data were pooled and a meta-analysis was completed for cardiorespiratory fitness (VO2peak). Results: We selected 8 studies, which included 305 patients with lung cancer: 6 studies were performed around surgical moment, one study during radiotherapy's treatment, and other during target therapy. After pooling the data, exercise capacity was included in the analysis. Results showed significant differences in favour to HIIT when compared to usual care in cardiorespiratory fitness (standard mean difference = 2.62; 95% confidence interval = 1.55, 3.68; p < 0.00001). Conclusions and implications: The findings indicated a beneficial effect of HIIT for improving cardiorespiratory fitness in lung cancer patients in early stages around oncological treatment moment. Nevertheless, this review has several limitations, the total number of studies was low, and the stage and subtype of lung cancer patients were heterogeneous that means that the conclusions of this review should be taken with caution.