New Research Suggests Preoperative High-intensity Interval Training is Beneficial for Cardiorespiratory Health

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Preoperative high-intensity interval training (HIIT) may improve cardiorespiratory fitness (CRF) and reduce postoperative complications, suggest findings from a recent systematic review and meta-analysis.

HIIT–which involves repeated aerobic high-intensity intervals at approximately 80% of the maximum heart rate, followed by active recovery–has previously been shown to increase CRF, according to researchers.

“The rapid increases in CRF elicited with HIIT is appealing for preoperative patients, and in the context of pathology, age, and comorbidities, the volume of training stimulus required to improve CRF can often be achieved,” wrote authors in JAMA Network Open.

Investigators from the University of Otago in New Zealand conducted the meta-analysis to summarize current data comparing the association of preoperative HIIT to standard hospital care with preoperative CRF and postoperative outcomes, including complications, hospital length of stay (LOS), and patient quality of life.

Researchers searched Medline, Embase, and other databases for randomized clinical trials and prospective cohort studies with HIIT protocols in adults undergoing major surgery. The primary outcome was change in CRF, as measured by either peak oxygen consumption (V̇o2 peak) or 6-Minute Walk Test distance, according to the study.

FINDINGS

A total of 12 eligible studies including 832 patients were identified. The mean age of participants was 66.5 years in the intervention group and 67.1 years in the control group, and the majority of participants in both groups were men (59.7% and 65.4%, respectively). Pooled results indicated several positive associations for HIIT compared with standard care on both CRF and postoperative outcomes, according to researchers.

In 8 studies including 627 patients, investigators found moderate-quality evidence of significant improvement in V̇o2 peak (cumulative mean difference 2.59mL/kg/min, 95% CI 1.52-3.65; P<.001). Also, in 8 studies including 770 patients, there was moderate evidence that preoperative HIIT reduces the odds of postoperative complications by 56% (odds ratio 0.44, 95% CI 0.32-0.60; P<.001).

Investigators did not find any evidence that HIIT differed from standard care in hospital LOS (cumulative mean difference -3.06 days, 95% CI -6.41 to 0.29 days; P=.07).

Further, the analysis showed an overall low risk of bias but a high degree of heterogeneity in study outcomes, indicated “the need for further well-designed studies to improve the quality of evidence and confirm effective HIIT protocols,” wrote researchers.

Limitations of the review and meta-analysis include study heterogeneity, incomplete reporting of findings, limited sample size, and lack of masking for participants, added investigators.

“The results of this meta-analysis suggest that preoperative HIIT may be beneficial for surgical populations through the improvement of exercise capacity and reduced postoperative complications. These findings support including HIIT in prehabilitation programs before major surgery,” concluded study authors.

Reference: Clifford K, Woodfield JC, Tait W, Campbell HA, Baldi JC. Association of preoperative high-intensity interval training with cardiorespiratory fitness and postoperative outcomes among adults undergoing major surgery: A systematic review and meta-analysis. JAMA Netw Open. 2023;6:e2320527.