Plasma Water T2 Is Associated With Exercise Duration In Females With Excess Body Weight

Plasma water T2, an indicator of metabolism-driven changes in the rotational/translational diffusion of water, has been suggested as a practical biomarker for the early detection of poor metabolic health. Water T2 detects early insulin resistance in individuals with normal blood glucose, triglycerides, hemoglobin A1C, and high-density lipoprotein. However, the relationship of T2 with cardiorespiratory fitness is unknown. PURPOSE: The overall objective of this research is to quantify the association between water T2 levels and cardiorespiratory fitness in untrained adults with overweight or obesity. METHODS: This is an observational cross-sectional study utilizing baseline samples from an ongoing clinical trial (ID: NCT05295719). Participants completed a modified Bruce cardiopulmonary exercise test (CPET) on a cycle ergometer. Anthropometric data was recorded and fasted blood samples were collected for assessment of metabolic and inflammatory markers, as well as water T2. A preliminary analysis was conducted with a machine-learning predictor screening of CPET variables (exercise duration, VO2max, etc.) with plasma water T2 as the outcome followed by a multivariable linear regression analysis with exercise duration as the outcome and plasma T2 as the primary exposure. RESULTS: Preliminary CPET data and blood samples from twenty females (age 32 ± 14 years, BMI 33 ± 4 kg/m2), and twelve males (age 35 ± 12.4 years, BMI 31.6 ± 4.6 kg/m2) were analyzed. Multi-variable linear regression, when stratified by sex, revealed plasma T2 as a significant predictor of exercise duration in females (p = 0.0273), but not in males (p = 0.9773). CONCLUSIONS: The association between T2 and exercise duration is influenced by sex, with plasma water T2 serving as a predictor of exercise duration during VO2max testing in females. These preliminary findings warrant further investigation. Supported by: USDA NIFA grant #2020-67034-31761