# 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

PMID: 32819304
Journal: BMC cancer
Published: 2020 Aug 20
Authors: Toohey K, Pumpa K, McKune A, Cooke J, Welvaert M, Northey J, Quinlan C, Semple S

## 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.

## Population

- Seventeen sedentary female breast cancer survivors completed the pilot RCT.
- Sample size: 17
- Age: Mean 62 +/- 8 years
- Sex: Female
- Fitness level: Sedentary
- Health status: Breast cancer survivors within 2 years after treatment

## Methodology

- Three-arm randomized controlled pilot trial
- 12 weeks
- University exercise laboratory
- Randomized and controlled study design.

## Protocol

- Cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 30 seconds as hard as possible.
- Recovery: 2 minutes active recovery.
- Sets or repetitions: 4 progressing to 7 intervals.
- Intensity: Hard/all-out effort; HR and RPE monitored.
- Session duration: 20-30 minutes.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Progressed to 7 intervals by week 4.
- CMIT and wait-list control.
- Modality: Cycle ergometer for CMIT; usual lifestyle for control.
- Work intervals: Continuous 20 minutes for CMIT.
- Intensity: 55%-65% maximal power, RPE 9-13 for CMIT.
- Session duration: 30 minutes for CMIT.
- Frequency: 3 sessions/week for CMIT.
- Program length: 12 weeks.

## Outcomes

### VO2peak
Status: improved
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
Status: no clear change
No significant group changes in HRV were observed.

All p>.05.

### Stress markers
Status: mixed
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
Status: improved
No adverse events were reported during supervised exercise.

## Practical 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 And Adherence

- No adverse events were reported.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/32819304/) (pubmed)
- [DOI](https://doi.org/10.1186/s12885-020-07295-1) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441660/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.