A short bout of preoperative high-intensity interval training (HIIT) improves cardiorespiratory fitness (CRF) for patients slated for major surgery. It cuts the risk of postoperative complications and may shorten hospital length of stay and improve postoperative quality of life.


Evidence suggests CRF ― which improves physical and cognitive function and is associated with a reduction in cardiovascular risk ― can be enhanced before major surgeries, but reported postoperative outcomes in previous reviews have been inconsistent.

In the study, HIIT involved repeated aerobic high-intensity exercise intervals at about 80% of maximum heart rate, followed by active recovery.

The meta-analysis included 12 studies with 832 patients (mean age, 67) that compared preoperative HIIT― supervised at hospitals, gyms, or community or physical therapy centers or unsupervised at home ― with standard care for patients slated for major surgery, including liver, lung, colorectal, urologic, and mixed major abdominal operations.

The primary outcome was change in CRF by peak VO2 or 6-minute walk test; other endpoints included change in endurance time and postoperative outcomes.


Preoperative HIIT (median total, 160 minutes; range, 80–240 minutes; intense exercise during six to 40 sessions) was associated with an increase in peak oxygen consumption (VO2 peak) by 2.59 mL/kg/min (95% CI, 1.52 – 3.65 mL/kg/min; P < .001) compared to standard care, which represents about a 10% increase in CRF.

In eight studies that involved 770 patients, there was moderate evidence that preoperative HIIT cut the odds ratio (OR) for postoperative complications by more than half (OR, 0.44; 95% CI, 0.32 – 0.60; P < .001); there was a similar apparent benefit in an analysis that was limited to patients who were slated for abdominal surgery (OR, 0.45; 95% CI, 0.29 – 0.68; P < .001).

An analysis that was limited to studies that reported hospital length of stay showed a clinically relevant but nonsignificant 3-day reduction among patients in the HIIT groups.

Most quality-of-life assessments did not show post-HIIT improvements; some showed a significant benefit 6 weeks after surgery.


The results suggest preoperative HIIT may improve postoperative outcomes. By extension, it could be cost-effective and “should be included in prehabilitation programs,” the report states.


The study was carried out by Kari Clifford, PhD, Otago Medical School, University of Otago, Dunedin, New Zealand, and colleagues. It was published online June 30, 2023, in JAMA Network Open.


Included studies were heterogeneous in methodology; for example, HIIT definitions and protocols varied across almost every study. Data reporting was incomplete, the samples sizes in the studies were limited, and patients could not be blinded to their intervention. The patients could not be stratified on the basis of frailty. There were limited HIIT data from patients who underwent orthopedic surgeries.


The study received funding from the University of Otago. The authors reported no conflicts.

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