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

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.