This thesis introduces a bioimpedance-based system for monitoring fluid balance during sports, integrating a Body Sensor Network (BSN) for measuring various physical parameters and a model to compensate for exercise-related fluid shifts. Validated through a clinical trial, the system addresses the crucial need for balanced hydration to optimize sports performance, as imbalances can hinder performance and impact health. Athletes can lose significant fluids—up to 4 liters per hour—during intense exercise, yet even professionals often struggle with hydration. Bioimpedance spectroscopy (BIS) is a recognized method for assessing hydration but requires strict measurement protocols, prohibiting exercise 24-48 hours prior to avoid skewed results due to metabolic changes. This limitation restricts BIS applicability for athletes. To enhance this, the Integrated Posture and Activity Network by MedIT Aachen (IPANEMA BSN) was developed, incorporating sensors to quantify exercise intensity alongside BIS measurements. The thesis expands the BIS model to account for dynamic metabolic changes and fluid shifts, modeling physiological processes like sweat production and muscle pressure conditions. Validation with 12 athletes demonstrated that simulation results closely matched observed fluid shifts during running, reducing BIS measurement errors by 80%. Ultimately, this research confirms the feasibility of monitoring athletes' hydration status u
