Cardiorespiratory fitness (CRF) improves physical and cognitive function and is associated with a lower risk of cardiovascular disease, diabetes, and cancer; fewer postsurgical complications; and improved health-related quality of life. An expanding body of evidence suggests that CRF can be increased preoperatively, improving postoperative outcomes.
The systematic review and meta-analysis of studies comparing prehabilitative high-intensity interval training (HIIT) with standard care in patients undergoing major surgery was published on June 30 in JAMA Network Open.
The meta-analysis included 12 studies with 832 patients (mean age, 67). Major surgery was defined in individual study methods and could include a procedure expected to last 2 hours or with an anticipated blood loss of greater than 500 mL. In the study, HIIT involved repeated aerobic high-intensity exercise intervals at about 80% of maximum heart rate, followed by active recovery. 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 no evidence that HIIT differed from standard care in hospital length of stay (cumulative mean difference, −3.06 days; 95% CI, −6.41 to 0.29 days; P = .07).
The analysis showed a high degree of heterogeneity in study outcomes and an overall low risk of bias.
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. The high degree of heterogeneity in both exercise protocols and study results supports the need for further prospective, well-designed studies.
