Heart rate and its variability are associated with resting metabolic rate and substrate oxidation in young women but not in men Alcántara Pilar, Juan Miguel González Acedo, Anabel Amaro Gahete, Francisco José Plaza-Florido, Abel gas exchange Kubios parasympathetic Background: This study aims to examine the relationship between resting vagal-related heart rate variability (HRV) parameters and heart rate (HR) with resting metabolic rate (RMR) and respiratory exchange ratio (RER) in young adults. Methods: A total of 74 young adults (22 ± 2 years old, 51 women) were included in this cross-sectional study. HRV was assessed using a HR monitor, whereas RMR and RER were determined by indirect calorimetry. Results: Linear regression analyses showed a positive association between HR and RER in women (standardized β = 0.384, p = 0.008), while negative associations were observed between vagal-related HRV parameters and RER in women (β ranged from −0.262 to −0.254, all p ≤ 0.042). No significant association was found between the abovementioned physiological parameters in men. Conclusion: Here, we show that HR is positively associated with RER in young women but not in men, while vagal-related HRV parameters are inversely related to RMR, therefore suggesting a potential sexual dimorphism between cardiac rhythm and its relationship with markers of cardiometabolic health status. 2024-10-07T08:59:07Z 2024-10-07T08:59:07Z 2024-09-20 journal article Alcántara Pilar, J.M. et. al. Am J Hum Biol e24157. [https://doi.org/10.1002/ajhb.24157] https://hdl.handle.net/10481/95604 10.1002/ajhb.24157 eng http://creativecommons.org/licenses/by-nc/4.0/ open access Atribución-NoComercial 4.0 Internacional Wiley Online Library