Does low volume high-intensity interval training elicit superior benefits to continuous low to moderate-intensity training in cancer survivors?
Question
To determine the impact of low-volume high-intensity interval training and continuous low-to-moderate intensity exercise training on cardiovascular disease risk and health outcomes in cancer survivors.
Summary
This randomized 12-week trial compared supervised low-volume high-intensity interval cycling, supervised continuous low-to-moderate intensity cycling, and a non-exercise control group in sedentary cancer survivors within 24 months of diagnosis. Low-volume HIIT improved six-minute walk distance, sit-to-stand performance, waist circumference, and quality of life more than the comparator groups, while both exercise groups improved quality of life. The protocol was short in high-intensity work time but supervised and clinically screened.
Methodology
- Sedentary cancer survivors within 24 months of diagnosis, mostly female breast cancer survivors in the post-treatment phase.
- 75 participants.
- Stationary cycling.
- Work intervals: 30 seconds.
- Recovery: 60 seconds.
- Intensity: >=85% predicted maximal heart rate.
- Approximately 16 minutes after full progression including warmup and cooldown.
- 3 sessions per week.
- 12 weeks.
- 12-week randomized controlled trial with three parallel groups: LVHIIT, CLMIT, and control.
- Six-minute walk test, Sit-to-stand test, Waist circumference, and Quality of life were tracked.
Outcomes
Six-minute walk test
LVHIIT increased six-minute walk distance from 510.7 +/- 114.9 m to 607.7 +/- 85.5 m, with a larger effect than CLMIT and control.
Interaction effect P<0.01; LVHIIT d=0.97 (95% CI 0.36, 1.56), CLMIT d=0.17, control d=-0.13.
Sit-to-stand
LVHIIT improved sit-to-stand time from 10.1 +/- 2.8 s to 8.1 +/- 2.1 s.
Interaction effect P<0.01; LVHIIT d=-0.83 (95% CI -1.40, -0.22), CLMIT d=-0.59, control d=0.36.
Waist circumference
LVHIIT reduced waist circumference from 91.1 +/- 11.7 cm to 85.7 +/- 10.5 cm, while CLMIT and control changed little.
Interaction effect P=0.01; LVHIIT d=-0.48 (95% CI -1.10, 0.10), CLMIT d=-0.05, control d=0.11.
Quality of life
Overall FACT-G quality of life improved in both exercise groups, with the largest effect in LVHIIT.
Interaction effect P<0.01; LVHIIT d=1.11 (95% CI 0.50, 1.72), CLMIT d=0.57, control d=-0.15.
Vessel stiffness parameters and biomarkers
No interaction effects were found for vessel stiffness parameters or biomarkers.
Authors reported no interaction effects; selected time effects included AP P=0.02 and CSP P=0.07.
Adverse events
No adverse events were reported during the study.
Insights
- In a clinically screened and supervised cancer survivor population, very short high-intensity cycling intervals can improve functional capacity and waist circumference over 12 weeks.
- Short hard-work time does not mean low supervision needs in clinical populations.
- Gradual progression from fewer intervals to the full interval count is a practical safety and tolerability feature.
Limitations
- Diet and daily physical activity outside sessions were not controlled.
- Cardiorespiratory fitness was assessed with six-minute walk rather than VO2max testing.
- No male participants completed the study.
- Different medications and cancer treatment protocols could have influenced results.
- The control group had high attrition.
Safety
- No adverse events were reported.
- Blood pressure was monitored immediately before and after each exercise session.
- Participants were clinically screened with exclusions for severe hypertension, pregnancy, brain or metastatic bone cancer, bone pain, and exercise-limiting musculoskeletal problems.