A Jacketed Telemetry Method for Monitoring Cardiorespiratory Adaptation During Exercise in Rats.

The assessment of cardiorespiratory adaptation during exercise is not only crucial for studying physiological adaptation to physical training, but also essential for preclinical research, as measurements at rest can mask underlying physiological phenomena. However, conventional preclinical methods, such as surgically implanted telemetry or hermetic chambers, come with important constraints. To overcome these limitations, we present a surgery-free methodology using a jacketed telemetry system, enabling the simultaneous monitoring of heart rate (HR), respiratory rate (RespR), and locomotor activity (AL) in rats during forced treadmill exercise. The protocol implements a two-phase acclimatization process designed to ensure both the appropriate running performance of the animals and data integrity: first, habituation to wearing the telemetry jacket, which integrates respiratory inductive plethysmography sensors and surface electrocardiogram electrodes; and second, a 2-week (five days per week) habituation to treadmill exercise. We detail equipment procedures and essential quality control steps, including real-time signal verification, to minimize animal stress and ensure reliable, low-noise physiological data. We also provide representative signal examples to help users achieve high data quality, especially during exercise protocols, but also in other experimental contexts. When implemented correctly, this protocol enables consistent monitoring at speeds up to 40 cm.s⁻1, allowing the quantification of changes in HR, RespR, and AL compared to baseline. By eliminating the need for surgical interventions, this protocol strongly adheres to the ethical principles of the 3Rs (reduce, refine, replace). While the provided techniques focus on exercise, they have potential applications across diverse fields, including comprehensive cardiorespiratory characterization, animal handling training, welfare monitoring, and physiology, pharmacology, or education.