Partial Metabolic Inflexibility is Associated with Higher Cardiovascular Strain and Altered Resting Physiology

Authors: Sophia Aparicio, Mariam Nada, Ronae Watson, Callen O’Connor, Rania Khan, Sara Saleh, Nema Sayeed, Maxime Argenson, Daniel Miller, Lina Begdache

Field of Study: Biological Sciences

Program Affiliation: Metabolic and Exercise Physiology Lab

Faculty Mentors: Daniel Miller, Lina Begdache

Easel: 8

Timeslot: Midday

Abstract: Metabolic inflexibility, the reduced ability to maintain favorable resting substrate use, may reflect broader physiological variation. Participants underwent resting metabolic rate testing and completed a series of validated surveys. They were categorized by the count of partial metabolic inflexibility criteria met (0, 1, or ≥2), and steady-state resting metabolic variables were compared using Kruskal–Wallis tests in Python 3.14.3. In the steady-state cohort (n=115), groups differed significantly in resting pulse (p<0.001), BMI, FeO2%, and ventilation rate (p<0.05). Notably, the ≥2 criteria group showed higher pulse (78.61 vs. 68.06 bpm), higher BMI (24.91 vs. 21.98 kg/m2), and higher ventilation (31.75 vs. 27.76 L/min) than the 1-criterion group. These findings suggest that the metabolically inflexible phenotype corresponds to greater cardiovascular strain, body-size burden or body composition, and altered gas-exchange rather than differences in resting metabolic rate alone.