Changes in Peak Aerobic Capacity During an 8-Month Period in First-Year Medical Students: A Prospective Pilot Cohort...

Background/Objectives: Medical school has long been thought to have a potentially detrimental effect on the health of its students. In this preliminary study, we sought to determine whether students experienced a decline in their cardiorespiratory physical fitness during an 8-month period of their first year of medical school. Methods: A single-center, uncontrolled prospective pilot cohort of first-year medical students (n = 13) from a single institution was recruited during their first month of school to undergo VO₂peak testing via indirect calorimetry. They were re-tested approximately 8 months later near the end of the academic year using the same protocol. Measurements of body mass, body fat percentage, and resting metabolic rate were also taken before VO₂peak testing. Participants were also asked to complete surveys related to diet, exercise, sleep, and mental health. Results: We were unable to recruit our planned sample size of n = 32 based on a priori power analysis. The final sample of 13 participants increased the risk of Type II error and limits the generalizability of these preliminary findings. We observed a statistically significant decrease in mean VO₂peak from 37.3 mL/kg/min to 35.0 mL/kg/min (mean change = -2.3, 95% CI [-4.3, -0.3], p = 0.048; median paired change = -2.1 [IQR: -4.3, -0.6]). An exploratory food-sufficiency measure showed a nominal decrease, whereas other self-reported lifestyle factors, body composition, and mental health measures did not show statistically detectable changes. Conclusions: In this small exploratory cohort, VO₂peak declined over the approximately 8-month observation period. No changes in self-reported lifestyle factors, body composition, or mental health reached preliminary statistical significance.