Association of Physical Fitness and Body Mass Index with Premature Discharge from Military Service-Study among...

The aim of this study was to investigate whether physical fitness and body mass index (BMI) are associated with premature discharge from military service because of health reasons.

The data was collected using a cross-sectional design and included the fitness test results and background information of Finnish conscripts (n = 228, 125) from 2012 to 2021. The physical fitness measures included a 12-minute running test, standing long jump, sit-up, and push-up tests. The BMI was calculated based on height and weight.

Conscripts in any of the lowest quartile of physical fitness were more likely to be discharged from their service compared to those in the highest quartiles (12-minute running test odds ratio (OR) 1.99; 95% confidence interval (CI) 1.88-2.11; standing long jump OR 1.45; 95% CI 1.38-1.53; sit-up test OR 1.46; 95% CI 1.38-1.54; and push-up test OR 1.50; 95% CI 1.42-1.59). The likelihood of being discharged from military service was higher among underweight (OR 1.35; 95% CI 1.22-1.50) and obese conscripts (OR 1.32; 95% CI 1.23-1.42) compared to normal weight conscripts. The most significant predictors for being discharged from service, found using backward elimination regression, were the 12-minute running test performance and BMI. The highest risk of being discharged from service was found to be among underweight conscripts with poor fitness.

Physical fitness and BMI were both associated with discharge from military service. Both under and overweight conscripts and those with poor physical fitness had a higher probability of being discharged from service. Therefore, the use of pre- and in service modifications to improve physical fitness and BMI could save resources for the Defence Forces and society as a whole.