Background: One of the most common and enduring cancer- and treatment-related side effects is fatigue. Fatigue affects 70-100% of cancer patients and endures for up to 10 years post-treatment. Evidence supports the prescription of exercise for the management of cancer-related fatigue; however, the influence of specific prescriptive parameters such as exercise intensity, is not yet fully elucidated.
Aim: To compare 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on fatigue in colorectal cancer (CRC) survivors.
Methods: Fifty-two CRC survivors (planned accrual target: n=27) (54% male; age 61±10 years; body mass index 26.9±4.5 kg.m-2; 4.1±2.5 years post-diagnosis) were randomised to either HIIT [4x4 min at 85–95% peak heart rate (HRpeak)] or MICT [50 min at 70% HRpeak; consistent with current physical activity guidelines]. Participants completed 24 training sessions over 8 weeks; sessions were supervised by accredited exercise physiologists. The primary endpoint was fatigue measured by the Functional Assessment of Chronic Illness Therapy – Fatigue questionnaire.
Results: Study completion rates for HIIT and MICT were 99.3 and 100.0%, respectively. Data were analysed using mixed effects modeling with Bonferroni adjustments for pairwise comparisons. Significant between-group differences (+3.1 points; p=0.008, 95% CI=0.011-1.00) were observed following the intervention, with HIIT eliciting a greater reduction in fatigue compared to MICT. A significant within-group reduction in fatigue was seen for the HIIT group (+3.9 points; p=0.015, 95% CI=-0.099--0.007), whereas no change was observed with MICT (+1.2 points; p>0.05). No serious adverse events occurred during the exercise sessions.
Conclusions: For CRC survivors, an 8-week HIIT program appears to offer clinically- and statistically-superior improvements in fatigue compared to MICT. Furthermore, MICT, aligned with current physical activity guidelines, did not appear to improve fatigue in CRC survivors. HIIT may therefore be an effective clinical utility for the reduction of fatigue in CRC survivors.