The impact of high-intensity interval training exercise on breast cancer survivors: a pilot study to explore fitness, cardiac regulation and biomarkers of the stress systems
Question
Can supervised HIIT improve fitness and stress-system biomarkers in breast cancer survivors compared with moderate continuous training or wait-list control?
Summary
In a small pilot RCT of sedentary breast cancer survivors, 12 weeks of supervised cycling HIIT improved VO2peak more than moderate cycling or a wait-list control. Attendance was similar between exercise groups and no adverse events were reported, but the sample was very small.
Methodology
- Seventeen sedentary female breast cancer survivors completed the pilot RCT.
- 17 participants.
- Cycle ergometer.
- Work intervals: 30 seconds as hard as possible.
- Recovery: 2 minutes active recovery.
- Intensity: Hard/all-out effort; HR and RPE monitored.
- 20-30 minutes.
- 3 sessions/week.
- 12 weeks.
- Three-arm randomized controlled pilot trial
- VO2peak, HRV, Salivary biomarkers, and Safety were tracked.
Outcomes
VO2peak
HIIT increased VO2peak by 19.3%, while CMIT and control did not significantly improve.
F2,12=6.53, p=0.01; HIIT B=3.98, 95% CI 1.88 to 6.02.
HRV
No significant group changes in HRV were observed.
All p>.05.
Stress markers
s-IgA did not change; cortisol slightly increased overall; s-AA response changes were not significant at group level.
s-cortisol time effect p=0.03; s-IgA p>.1; s-AA group changes p>.2.
Safety
No adverse events were reported during supervised exercise.
Insights
- Short hard cycling intervals can improve VO2peak in selected sedentary breast cancer survivors when supervised.
- Attendance was comparable between HIIT and moderate-intensity cycling.
Limitations
- Very small pilot sample.
- Treatment imbalance across groups.
- Unobserved saliva collection.
- Generalizability limited to selected survivors able to cycle.
Safety
- No adverse events were reported.