Training and lung complications: a 29-trial meta-analysis

A systematic review and meta-analysis pooled 29 randomised trials with 2,070 adults awaiting cardiac, lung, oesophageal or abdominal surgery. It compared people who trained before the operation with people who received usual care or sham training. Training was associated with fewer pulmonary complications after surgery (relative risk 0.52).

VO₂max and fitness before surgery

VO₂max, maximum oxygen consumption, measures how much work the heart, lungs and muscles can sustain together. At the end of the preparation period, peak oxygen uptake was 2 ml/kg/min higher in the trained groups.

The authors start from an observation: poor fitness and weak respiratory muscles before surgery are associated with more pulmonary complications. In the trained groups the hospital stay was 2.3 days shorter; postoperative mortality did not change.

In the groups that trained, pulmonary complications after surgery (for example pneumonia or atelectasis) were about half those of the control groups: 48% fewer, across 23 trials and 1,864 patients, with moderate-quality evidence according to the authors. It is an average across many studies, not a forecast for one person.

How much and what kind of training

The meta-analysis found no difference in effect by type of surgery, by type of training (respiratory muscles, endurance or both) or by how long people trained before the operation. Which training, and for how long, is decided by the care team, person by person.

Many sports watches give an estimate of VO₂max: it is an estimate, not the result of a laboratory exercise test.

The Digital Twin and this research

The Digital Twin lines up the data your devices write to your phone, such as steps, heart rate and sleep, and shows you how they change over time. It does not calculate whether you are ready for surgery and it does not diagnose: this research describes groups of people, not you. Preparation for surgery is decided and followed by the care team.