Preoperative exercise was significantly associated with a reduced risk of postoperative venous thromboembolism in a dose-dependent manner, with patients exercising ≥3 times per week showing the lowest and statistically significant risk reduction (aOR: 0.66, 95% c.i.: 0.45-0.96).
Key Findings
Results
Preoperative exercise was significantly associated with a reduced risk of postoperative VTE compared to no exercise.
Total cohort included 118,340 patients from the National Health Insurance Service-National Sample Cohort (2009-2016)
Adjusted odds ratio for VTE among exercisers versus non-exercisers was 0.69 (95% c.i.: 0.49-0.99, P = 0.041)
Multivariable logistic regression adjusted for demographic, clinical, and surgical factors was used
Results
A dose-response relationship was observed between preoperative exercise frequency and postoperative VTE risk.
Exercising 1-2 times per week was associated with a lower but non-significant VTE risk (aOR: 0.79, 95% c.i.: 0.48-1.26, P = 0.334)
Exercising ≥3 times per week was associated with the lowest and statistically significant VTE risk (aOR: 0.66, 95% c.i.: 0.45-0.96, P = 0.031)
P for trend across frequency categories was 0.032, confirming a statistically significant dose-response relationship
Exercise was classified as none, 1-2 times/week, or ≥3 times/week
Results
Secondary analyses confirmed protective trends of preoperative exercise for deep vein thrombosis specifically.
Similar protective trends for deep vein thrombosis were confirmed in secondary analyses
Varying degrees of risk reduction were also observed for other complications such as stroke
The paper does not report specific aOR values for DVT alone in the abstract
Results
The protective effect of preoperative exercise on postoperative outcomes was more pronounced in male and smoking patients.
Subgroup analyses were conducted across demographic and lifestyle strata
The impact of exercise was described as 'more pronounced in male and smoking patients'
Specific subgroup odds ratios for male and smoking patients are not provided in the abstract
Conclusions
Preoperative exercise was identified as an independent, modifiable factor associated with reduced postoperative VTE risk.
Exercise status was assessed via preoperative health screening within the National Health Insurance Service-National Sample Cohort
The association remained significant after adjustment for demographic, clinical, and surgical factors
The study characterized preoperative exercise as 'a non-pharmacological strategy to enhance surgical safety'
The study design was a nationwide population-based cohort study using data from 2009-2016
What This Means
This research suggests that patients who exercise regularly before surgery have a meaningfully lower chance of developing dangerous blood clots (venous thromboembolism, or VTE) after their operation. Using a large national database of over 118,000 South Korean adults who had surgery between 2009 and 2016, researchers found that people who exercised before surgery were about 31% less likely to develop postoperative blood clots compared to those who did not exercise. The benefit appeared strongest for those exercising at least three times per week, who had a 34% lower risk, while those exercising one to two times per week showed a trend toward lower risk that did not reach statistical significance.
The study also found a clear 'dose-response' pattern — meaning more frequent exercise was linked to greater protection — which strengthens the case that exercise itself, rather than some other unmeasured factor, is driving the reduction in clot risk. The protective effect appeared especially strong among male patients and those who smoked. Similar protective trends were found specifically for deep vein thrombosis (clots in the legs) and to some degree for stroke risk as well.
This research suggests that encouraging patients to exercise regularly in the weeks before a planned surgery — a concept known as 'prehabilitation' — could serve as a practical, low-cost strategy to reduce serious postoperative complications without medication. Because the study was observational and conducted in a single country's insurance database, further research would be needed to confirm these findings in other populations and to determine exactly what types and amounts of exercise are most beneficial.
Kim C, Park B, Yoon H, Sim J. (2026). Association between preoperative physical exercise and the risk of postoperative venous thromboembolism: nationwide population-based cohort study.. BJS open. https://doi.org/10.1093/bjsopen/zrag109