CATEGORY: EXERCISE & MOVEMENT
What does it buy a patient to get fitter before an operation? Researchers pooled 186 randomized trials of prehabilitation, covering 15,684 surgical patients, to find out. Patients put on an exercise program in the weeks before major surgery had about half the odds of a complication afterward and left the hospital nearly a day sooner, according to the analysis published in The BMJ.1 Nutrition support beforehand lowered the odds of complications by 38%. The elaborate multi-part programs many hospitals favor did no better than exercise on its own.
Getting in Shape for an Operation, Tested 186 Times
Prehabilitation is a structured program of preparation in the weeks before surgery, and it rests on a simple idea. An operation is a physical ordeal, and the body that arrives fitter weathers it better, much as a hiker who trains before a mountain handles the climb better than one who starts cold. The researchers gathered every randomized trial that tested at least seven days of preparation, built from exercise, nutrition support, psychological preparation, thinking exercises or combinations of those, then compared each approach against usual care and against the others. Every trial had allotted its patients a program at random rather than letting them choose, which is why the groups started out alike and why differences in how they fared can be credited to the preparation. Nearly half the operations studied were cancer surgeries. About a quarter were orthopedic procedures such as joint replacements, and the rest included heart, blood vessel and other major operations.
Half the Odds of Trouble, and Almost a Day Less in the Hospital
Patients on exercise-only programs had 50% lower odds of a complication after surgery than patients given usual care, problems such as infections, breathing trouble or poor wound healing. Their hospital stays ran 0.93 days shorter on average. Nutrition-only programs, typically protein supplements or dietary counseling, went with 38% lower odds of complications and stays about a day shorter. Exercise paired with psychological support showed the largest cut in time in the hospital, at 2.44 fewer days. None of this came from exotic training. Most of the exercise programs were ordinary aerobic conditioning, walking or cycling, often with basic strength work, done at home or in a clinic in the last few weeks before the operation.
The Teamwork the Researchers Expected, and Did Not Find
The study team included patients and caregivers as partners, and it went in expecting the combinations to win. Those partners, the authors wrote, had expressed a strong belief in the likely underlying clinically meaningful interaction of different prehabilitation components. The data said otherwise. A three-part combination of exercise, nutrition and psychological support lowered the odds of complications by 36%, a real benefit but no better than exercise alone. No multi-part program beat the single ingredients it was built from.
Why the Certainty Is Graded Low Anyway
Most of the 186 trials were small and many had design weaknesses, so the authors rate the certainty of the evidence as low to very low overall. The true sizes of these effects could shift as larger trials report. The core findings were not fragile, though. Restricted to the trials at lowest risk of bias, the benefits of exercise and of nutrition support held up. An independent group reached a matching conclusion after pooling 25 randomized trials of 2,674 patients preparing for major abdominal operations: aerobic exercise beforehand lowered the odds of complications by 39%, and pairing it with inspiratory muscle training, which is breathing exercises against resistance that strengthen the muscles used to fill the lungs, went with far fewer pneumonias afterward, about 138 fewer cases for every 1,000 patients.2
Key Takeaways
- Exercise programs in the weeks before major surgery halved the odds of complications afterward and shortened hospital stays by nearly a day, pooled across 186 trials and 15,684 patients.
- Nutrition support lowered complication odds by 38%. Combination programs helped, but no more than exercise alone, which is the opposite of what the research team expected.
- The evidence is rated low-certainty overall because many trials were small, yet the exercise and nutrition results held when only the most rigorous trials were counted.
- An independent pooled analysis of abdominal surgery trials found the same pattern, with breathing-muscle training linked to markedly fewer pneumonias.
References
- McIsaac DI, Kidd G, Gillis C, et al. Relative efficacy of prehabilitation interventions and their components: systematic review with network and component network meta-analyses of randomised controlled trials. BMJ. 2025;388:e081164. link
- Ricci C, Alberici L, Serbassi F, et al. Physical Prehabilitation in Patients who Underwent Major Abdominal Surgery: A Comprehensive Systematic Review and Component Network Meta-Analysis Using GRADE and CINeMA Approach. Annals of Surgical Oncology. 2024;31(3):1725–1738. link