Purpose: High-intensity interval training (HIIT) is a time-efficient and promising tool for enhancing physical fitness. However, there is lack of research concerning safety and feasibility of HIIT in cancer survivors. Therefore, two different HIIT protocols were investigated in terms of safety, feasibility, and acute exercise responses.
Methods: Forty cancer survivors (20 breast and 20 prostate cancer survivors, 62.9 ± 9.2 yr, BMI 27.4 ± 3.9 kg·m, 6 to 52 wk after the end of primary therapy) completed a maximal cardiopulmonary exercise test and two HIIT protocols on a cycle ergometer: 10 × 1 min at peak power output (10 × 1) and 4 × 4 min at 85%-95% peak HR (4 × 4). Safety (adverse events), acute physiological responses (HR, blood lactate concentration) and acute psychological responses (RPE, enjoyment) were recorded.
Results: No major but three minor adverse events occurred. Ninety-five percent of participants were able to complete each HIIT protocol. Estimated energy expenditure (159 ± 15 vs 223 ± 45 kcal, P < 0.001), HR (128 ± 20 vs 139 ± 18 bpm; P < 0.001), blood lactate concentration (5.4 ± 1.0 vs 5.9 ± 1.9 mmol·L; P = 0.035), and RPE legs/breathing (13.8 ± 2.0/13.1 ± 2.0 vs 14.6 ± 2.1/14.3 ± 2.0; P = 0.038/0.003) were significantly higher in the 4 × 4. Enjoyment did not differ between protocols (P = 0.301).
Conclusions: The two HIIT protocols as single sessions appear safe and in the vast majority of breast and prostate cancer survivors after the end of primary therapy also feasible and enjoyable. The 4 × 4 elicited higher energy expenditure and higher cardio-circulatory and metabolic strain and might therefore be preferred if a high training stimulus is intended.