Unveiling the Bohr Effect through Modern Biochemical Modeling of Invasive Exercise Physiology Data
Research Project | 1 Project Members
The transport of oxygen (O₂) and carbon dioxide (CO₂) by hemoglobin (Hb) is critical for maintaining homeostasis, and the oxygen dissociation curve (ODC) is central to understanding this process. While the Bohr effect, which describes the modulation of Hb’s affinity for O₂ by factors like pH, CO₂, and temperature, is well established, the dynamics of this effect in vivo—especially in relation to the ODC’s inflection point—remain insufficiently understood. The inflection point of the ODC, which is not to be confused with the O₂ partial pressure at 50% saturation, is thought to represent a critical transition in O₂ unloading, but it has received limited attention in the literature despite its potential physiological relevance. Recent work has suggested that this inflection point may align with the anaerobic threshold (gas exchange threshold = GET), where the Bohr effect is triggered, yet no study has fully explored this phenomenon under in vivo conditions.
This study aims to address this significant gap by combining highly invasive cardiopulmonary exercise testing (CPET) data with state-of-the-art biochemical modeling of O₂, CO₂, and H⁺ binding to Hb. Using a unique dataset from completed CPET studies, where blood was sampled simultaneously from femoral venous, mixed-venous, and arterial blood, this project will explore the dynamics of the ODC inflection point during exercise. The goal is to investigate how the interaction between CO₂ and H⁺ binding to Hb changes as O₂ saturation crosses the inflection point, and to link this shift with the activation of the Bohr effect and the GET.
This research is expected to provide novel insights into the optimal point of O₂ unloading and its relationship to the Bohr effect, a question that has remained unresolved since the discovery of the ODC over a century ago. By elucidating these mechanisms, this study aims to deepen our understanding of cardiorespiratory physiology and enhance clinical applications in exercise physiology, critical care, and blood gas analysis. The findings may lead to improved methods for interpreting blood gas data and refining therapeutic interventions in both athletic and clinical settings.
