Diabetes Alters Cardiorespiratory Dynamics: Insights from Short-Term Recurrence Quantification Analysis of Pulse-Respiration Quotient

José Javier Reyes-Lagos ¹ Kioko Rubi Guzman-Ramos ^2* Joel Lomeli ³ Adriana Pliego ¹ Miguel Ángel Peña-Castillo ⁴ Pedro López-Sánchez ³ Virgilio Eduardo Trujillo- Condes ¹ Laura Ivoone Garay-Jiménez ⁵ Juan C Echeverría ⁴ María Fernanda Villegas-Zarco ⁶ Laura Mercedes Santiago-Fuentes ^1,4

• ¹ Universidad Autónoma del Estado de México, Toluca, Mexico
• ² Autonomous Metropolitan University, Lerma, Lerma, Campeche, Mexico
• ³ Escuela Superior de Medicina (IPN), Mexico City, México, Mexico
• ⁴ Autonomous Metropolitan University, Iztapalapa, México, Mexico
• ⁵ Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas, Instituto Politécnico Nacional, Ciudad de México, Mexico
• ⁶ Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, México, Mexico

The Pulse-Respiration Quotient (PRQ) is considered as a powerful tool for assessing dynamic interactions between cardiac and respiratory rhythms. Type 2 diabetes mellitus (T2DM) disrupts the autonomic control, which may result in a compromise of the complexity and adaptability of the cardiorespiratory dynamic. In this cross-sectional, exploratory study, we investigated whether T2DM alters the cardiorespiratory dynamics by analyzing short-term PRQ signals through conventional linear indices and Recurrence Quantification Analysis (RQA).Thirty-eight participants (20 T2DM and 18 controls) completed four standardized tasks—supine rest, orthostatic challenge, paced breathing, and the Valsalva maneuver—while electrocardiographic and respiratory signals were continuously recorded. From these signals, R-to-R peak interval (RRI) and breath-to-breath (BB) time series were derived, allowing us to compute the PRQ time series as the ratio of instantaneous heart rate to instantaneous breathing rate. Linear indices of PRQ and RQA metrics were then calculated for the PRQ signals, enabling comparisons between groups (T2DM vs. control) and across tasks. Additionally, entropy-based mutual information (MI) between RRI and BB was assessed as a quantitative measure of cardiorespiratory coupling.Our results indicated that T2DM participants displayed higher recurrence rates and prolonged recurrence time of the first type in the PRQ series, particularly during paced breathing, suggesting a more rigid and less adaptive control mechanism. Although linear PRQ indices showed changes in some stage-dependent responses, these indices were less adept than those from the RQA to distinguish subtler differences between groups. The complementary cardiorespiratory coupling assessment by MI revealed distinct compensatory patterns in T2DM during paced respiration and Valsalva, suggesting potential dysautonomia or partial autonomic dysregulation.