# Short-term pre-operative high-intensity interval training does not improve fitness of colorectal cancer patients

PMID: 31116453
Journal: Scandinavian journal of medicine & science in sports
Published: 2019 Sep
Authors: Boereboom CL, Blackwell JEM, Williams JP, Phillips BE, Lund JN

## Question

Can a short pre-operative cycling HIIT program improve cardiopulmonary fitness in colorectal cancer patients before surgery?

## Summary

In colorectal cancer patients waiting for surgery, a short supervised cycling HIIT program was completed with full compliance and no clinically significant HIIT-related adverse events, but it did not significantly improve VO2peak or anaerobic threshold. Some blood-pressure and exercise-efficiency measures improved, so this is a useful cautionary paper: very short pre-operative HIIT may be feasible but should not be promised to raise fitness.

## Population

- Colorectal cancer patients awaiting surgery without neoadjuvant therapy
- Sample size: 18
- Age: 67 +/- 8 years
- Sex: 13 men, 5 women
- Fitness level: Mostly inactive
- Health status: Pre-operative colorectal cancer population with varied comorbidities

## Methodology

- Prospective single-arm pre-operative intervention study
- About 19 +/- 7 days of training before surgery
- Hospital pre-operative clinical exercise testing and supervised cycling HIIT

## Protocol

- Pre-operative cycling HIIT.
- Modality: Stationary cycling.
- Work intervals: 1 minute.
- Recovery: 90 seconds unloaded active recovery.
- Sets or repetitions: 5 intervals.
- Intensity: 100%-120% of baseline CPET maximum wattage.
- Session duration: About 15 minutes including warm-up and monitoring.
- Frequency: 3 to 4 times/week.
- Program length: Mean 19 +/- 7 days.
- Progression: Workload set individually from CPET/HIIT assessment.

## Outcomes

### VO2peak
Status: no clear change
VO2peak did not significantly improve after the short HIIT program.

23.9 +/- 7.0 to 24.2 +/- 7.8 mL/kg/min; table p=0.47

### Anaerobic threshold
Status: no clear change
Anaerobic threshold did not significantly improve.

14.0 +/- 3.4 to 14.5 +/- 4.5 mL/kg/min; p=0.50

### Exercise tolerance
Status: improved
Time to failure and maximum wattage improved.

Time to failure p=.02; maximum wattage p=.007

### Blood pressure
Status: improved
Resting systolic blood pressure decreased.

152 +/- 19 to 142 +/- 19 mmHg; p=.0005

## Practical Insights

- Very short HIIT blocks should not be expected to reliably improve VO2peak.
- A compact 5 x 1-minute cycling structure may be feasible under clinical supervision.
- For frontend, emphasize feasibility and null fitness result rather than benefit claims.

## Limitations

- Small sample
- No control group
- Not randomized
- Very short intervention
- Clinical pre-operative cancer population
- Surgery timing constrained dose

## Safety And Adherence

- No clinically significant adverse events related to HIIT occurred.
- Participants were clinically screened and monitored; surgery was not delayed.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/31116453/) (pubmed)
- [DOI](https://doi.org/10.1111/sms.13460) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771883/) (full text)

## Agent Guidance

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