# Short-term high-intensity interval training improves fitness before surgery: A randomized clinical trial

PMID: 35088469
Journal: Scandinavian journal of medicine & science in sports
Published: 2022-05-01
Authors: Woodfield JC, Clifford K, Wilson GA, Munro F, Baldi JC

## Question

Can a short preoperative HIIT program improve VO2peak before major abdominal surgery, and what postoperative clinical signals are observed?

## Summary

This single-center randomized trial tested whether a short, supervised HIIT program could improve fitness before major abdominal surgery. Patients aged 45-85 were assigned to standard care or about 14 HIIT cycling sessions over 4 weeks. The HIIT group improved VO2peak by about 2.7 mL/kg/min more than standard care and also improved peak work rate. Clinical outcomes such as complications and hospital stay numerically favored HIIT but were not statistically significant. The program was fairly intense and frequent, averaging 3.7 sessions per week and about 100 total minutes of intense exercise, with minimal adverse events under supervision.

## Population

- Adults aged 45-85 scheduled for major abdominal surgery.
- Sample size: 63
- Age: Median 66-66.5 years by group.
- Sex: Exercise 20 male/8 female; control 18 male/17 female.
- Fitness level: Preoperative surgical candidates with baseline VO2peak around 20-22 mL/kg/min.
- Health status: Major abdominal surgery candidates; medically screened for exercise contraindications.

## Methodology

- Single-center, two-arm, parallel, prospective randomized controlled trial.
- 4 weeks / approximately 14 sessions before surgery.
- Preoperative hospital-linked supervised exercise program using stationary cycling.
- Randomized and controlled study design.

## Protocol

- 4-week preoperative cycling HIIT.
- Modality: Stationary cycling.
- Work intervals: Initially 1-minute high-intensity intervals; progression toward 2-minute intervals.
- Recovery: Initially 1-minute active rest at >=60% HRmax; later 1-2 minutes lower-intensity cycling.
- Sets or repetitions: Initially about ten 1-minute intervals; aim toward five 2-minute intervals.
- Intensity: Goal to reach 90% HRmax at least once per session and then in as many intervals as possible.
- Session duration: Approximately 30 minutes.
- Frequency: About 3.7 sessions per week on average.
- Program length: 4 weeks / 14 prescribed sessions.
- Progression: Increase load or intense interval duration; start with shorter intense bouts if comorbidities required.
- Standard preoperative care.
- Modality: Advice and usual perioperative preparation.
- Intensity: Encouraged to exercise more; no supervised intensity prescription.
- Program length: Preoperative period.

## Outcomes

### VO2peak
Status: improved
HIIT improved VO2peak meaningfully more than standard care.

HIIT +2.87 +/- 1.94 vs standard care +0.15 +/- 1.93 mL/kg/min; difference 2.73, 95% CI 1.53 to 3.93, p < 0.001.

### Peak work rate
Status: improved
Peak work rate increased significantly in the exercise group compared with control.

p = 0.037 per-protocol; p = 0.05 ITT.

### Clinical outcomes
Status: mixed
Complications, length of stay, and SF-36 physical component numerically favored HIIT but were not statistically significant overall.

Complications per patient 0.64 vs 1.16, p = 0.072; mean LOS 5.5 vs 7.4 days adjusted p = 0.067; PCS overall adjusted p = 0.057.

### Adverse events
Status: mixed
Two safety events were documented and resolved after stopping: arrhythmia during CPET and chest pain during HIIT.

## Practical Insights

- HIIT can improve VO2peak within 4 weeks when frequency and intensity are high.
- A small amount of total hard work, about 100 minutes over the program, produced a meaningful VO2peak gain under supervision.
- Short-term fitness gains do not automatically prove fewer complications; outcome-powered trials are needed.
- High-risk users need screening because CPET and HIIT revealed cardiac symptoms/events.

## Limitations

- Underpowered for postoperative outcomes.
- Patient blinding impossible.
- Control-group disappointment and exercise contamination.
- Selected motivated patients near hospital.
- Supervised clinical context limits consumer generalization.

## Safety And Adherence

- New arrhythmia diagnosed during initial CPET.
- Chest pain during HIIT.
- Both events resolved on stopping the intervention without sequelae.
- Safety committee reviewed protocols and adverse events.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/35088469/) (pubmed)
- [DOI](https://doi.org/10.1111/sms.14130) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9306492/) (full text)

## Agent Guidance

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