Cardio-respiratory coherence: a solution for restoring psycho-physical well-being, resilience, and optimal performance

Dario Boschiero1,2, Francesco Cuzzolin2,3, Michele Marro1,2, Francesca Ferrari1,2, Gianfranco Beltrami4, Sergio Pecorelli5

1Open Academy of Medicine, London, UK; 2BioTekna, Research & Development Department, Venice, Italy; 3Saint Anthony Catholic University, UCAM - Centro de Investigación en Alto Rendimiento Deportivo, Spain; 4University of Parma and San Raffaele- Uniroma 5, Italian Federation of Sports Medicine (FMSI), Rome, Italy; 5Giovanni Lorenzini Medical Foundation, Milan, Italy, Scientific & Cultural Committee Italian Federation of Sports Medicine (FMSI), Rome, Italy.

Summary. Cardio-respiratory coherence or Respiratory Sinus Arrhythmia (RSA) represents an innovative and increasingly studied technique for the recovery of psychophysical well-being. It integrates the control of heart rate variability (HRV) with mindful breathing and BioFeedback at specific frequencies and breathing patterns. This state of synchronization between heart rhythm and breathing has been associated with numerous benefits, including stress reduction, improved emotional regulation, enhanced cognitive, physical, and athletic performance, and strengthened psychophysical resilience. This review explores the underlying mechanisms of cardio-respiratory coherence, with particular attention to the interac-tion between the autonomic nervous system and the cardiovascular system. Furthermore, the effects of cardio-respiratory coherence on mental and physical health are examined through the analysis of recent studies, highlighting the potential of this practice as a non-pharmacological therapeutic intervention for stress-related disorders, anxiety, depression, and psychophysical health and performance. The findings suggest that integrating cardio-respiratory coherence into care protocols and prevention programs may represent an effective strategy for the recovery and maintenance of psychophysical well-being.

Key words. Cardio-respiratory coherence, Respiratory Sinus Arrhythmia, cardiac coherence, HRV, heart rate variability, mindful breathing, stress, emotional regulation, cognitive performance, physical performance, resilience, autonomic nervous system, ANS, anxiety, depression, well-being, health.

Coerenza cardio-respiratoria: una strategia per il ripristino del benessere psicofisico, della resilienza e della performance ottimale

Riassunto. La coerenza cardio-respiratoria, o Aritmia Sinusale Respiratoria (RSA), rappresenta una tecnica inno-vativa e sempre più oggetto di studio per il recupero del benessere psicofisico. Essa integra il controllo della variabilità della frequenza cardiaca (HRV) con la respirazione consapevole e il Biofeedback, applica-ti a specifiche frequenze e schemi respiratori. Questo stato di sincronizzazione tra il ritmo cardiaco e la respirazione è stato associato a numerosi benefici, tra cui la riduzione dello stress, il miglioramento della regolazione emotiva, l’incremento delle performance cognitive, fisiche e sportive, nonché il rafforzamento della resilienza psicofisica. La presente review analizza i meccanismi alla base della coerenza cardio-respiratoria, con particolare attenzione all’interazione tra il sistema nervoso autonomo e il sistema cardiovascolare. Inoltre, vengono esaminati gli effetti della coerenza cardio-respiratoria sulla salute mentale e fisica attraverso l’analisi di studi recenti, evidenziando il potenziale di questa pratica come intervento terapeutico non farmacologico nei disturbi correlati allo stress, nell’ansia, nella depressione e nella promozione della salute e della performance psicofisica. I risultati suggeriscono che l’integrazione della coerenza cardio-respiratoria nei protocolli di cura e nei programmi di prevenzione possa rappresentare una strategia efficace per il recupero e il mantenimento del benessere psicofisico.

Parole chiave. Coerenza cardio-respiratoria, Aritmia Sinusale Respiratoria, coerenza cardiaca, HRV, variabilità della frequenza cardiaca, respirazione consapevole, stress, regolazione emotiva, performance cognitiva, per-formance fisica, resilienza, sistema nervoso autonomo, SNA, ansia, depressione, benessere, salute.

Introduction

Psychophysical well-being is essential for quality of life, influencing not only mental health but also the physiological functioning of the body. In a social context characterized by an increasingly fast pace of life and a rise in stress factors, it has become crucial to develop and implement effective strategies for the recovery and maintenance of psychophysical well-being. Among the various emerging techniques, cardio-respiratory coherence, or Respiratory Sinus Arrhythmia (RSA), stands out for its integrated approach aimed at synchronizing heart rhythm with mindful breathing, fostering a state of balance between the sympathetic and parasympathetic nervous systems. Cardio-respiratory coherence is a practice based on the regulation of heart rate variability (HRV), a key indicator of cardiovascular health and resilience to stress. The synchronization of the heartbeat with the respiratory cycle, characteristic of cardio-respiratory coherence (RSA), promotes a range of physiological responses that can reduce stress levels, improve emotional regulation, and enhance cognitive functions. Recent studies suggest that cardio-respiratory coherence may have significant clinical applications, particularly in the management of stress-related disorders, anxiety, and depression, as well as in the prevention of cardiovascular diseases. The growing interest in cardio-respiratory coherence is fueled by an increasingly robust body of scientific evidence supporting its effec-tiveness. However, despite the numerous reported benefits, cardio-respiratory coherence (RSA) remains relatively unknown and underutilized in clinical and preventive settings. This paper aims to explore the physiological mechanisms underlying cardio-respiratory coherence, analyze its effects on psychophysical health, and discuss its potential therapeutic applications1-4.

Methods

A search strategy was employed on the PubMed database using the following keywords: (coherence cardio-respiratory) OR (RSA) OR (Respiratory Sinus Arrhythmia) OR (cardiac coherence) OR (HRV AND coherence cardio-respiratory) OR (heart rate variability AND coher-ence cardio-respiratory) OR (mindful breathing AND coherence cardio-respiratory) OR (stress AND coherence cardio-respiratory) OR (emotional regulation AND coherence cardio-respiratory) OR (cognitive performance AND coherence cardio-respiratory) OR (physical performance AND coherence cardio-respiratory) OR (resilience AND coherence cardio-respiratory) OR (autonomic nervous system AND coherence cardio-respiratory) OR (ANS AND coherence cardio-respiratory) OR ((anxiety OR depression) AND coherence cardio-respiratory) OR ((well-being OR health) AND coherence cardio-respiratory) OR (HRV AND Respiratory Sinus Arrhythmia) OR (heart rate variability AND Respiratory Sinus Arrhythmia) OR (mindful breathing AND Respiratory Sinus Arrhythmia) OR (stress AND Respiratory Si-nus Arrhythmia) OR (emotional regulation AND Respiratory Sinus Arrhythmia) OR (cogni-tive performance AND Respiratory Sinus Arrhythmia) OR (physical performance AND Res-piratory Sinus Arrhythmia) OR (resilience AND Respiratory Sinus Arrhythmia) OR (auto-nomic nervous system AND Respiratory Sinus Arrhythmia) OR (ANS AND Respiratory Sinus Arrhythmia) OR ((anxiety OR depression) AND Respiratory Sinus Arrhythmia) OR ((well-being OR health) AND Respiratory Sinus Arrhythmia). No restrictions were applied regard-ing publication language, date, or study design. The reference lists of relevant articles were manually reviewed to identify potentially eligible studies (“snowball” procedure) to maxim-ize the amount of synthesized data. Interventional, prospective, and retrospective studies, as well as narrative and systematic reviews and meta-analyses, were included5-10.

Cardio-respiratory coherence or Respiratory Sinus Arrhythmia

Cardio-respiratory coherence is a physiological state in which heart rhythm and breathing are harmoniously synchronized, creating a rhythmic and regular flow between the heart and lungs. This state of coherence has significant implications for physical and mental well-being, positively influencing the autonomic nervous system and enhancing calmness and focus4,11-14.

Physiological foundations of cardio-respiratory coherence

To understand cardio-respiratory coherence, it is essential to explore the interactions be-tween the cardiovascular and respiratory systems15-19:

1. Heart Rhythm (Heart Rate): the heart beats at a rhythm that can vary based on numerous factors, including stress, physical activity, emotions, and breathing. The variation in heart rhythm is measured as Heart Rate Variability (HRV).

2. Breathing: the process of inhalation and exhalation directly influences heart rhythm. During inhalation, heart rate tends to increase, while during exhalation, it decreases. This phenomenon is known as the respiratory effect on heart rate.

3. Autonomic Nervous System (ANS): the ANS is divided into two main branches:

• Sympathetic: responsible for the “fight or flight” response, increasing heart rate and preparing the body for action.

• Parasympathetic: promotes relaxation and recovery, decreasing heart rate and facilitating digestion and rest.

Respiratory effect on heart rate

The process of inhalation and exhalation directly affects heart rhythm through a phenome-non known as Respiratory Sinus Arrhythmia (RSA). This is a natural physiological process in which heart rate varies synchronously with breathing, increasing during inhalation and decreasing during exhalation. This phenomenon is linked to how the autonomic nervous sys-tem regulates both respiration and heartbeat. The autonomic nervous system (ANS) is responsible for the involuntary control of vital functions such as heart rate, respiration, and di-gestion.

4. Sympathetic Nervous System: involved in the “fight or flight” response, preparing the body to handle stress by increasing heart rate, blood pressure, and priming the muscles for action.

5. Parasympathetic Nervous System: has the opposite effect, activating the “relaxation re-sponse,” reducing heart rate, and promoting recovery and relaxation.

The vagus nerve, a key component of the parasympathetic system, plays a crucial role in regulating heart rate in response to breathing. During the respiratory cycle, breathing alternately influences these two systems, resulting in variations in heart rhythm20-24.

Mechanism of Heart Rate Increase During Inhalation

During inhalation, heart rate increases due to a series of interconnected physiological mech-anisms primarily mediated by the autonomic nervous system25-29. The process unfolds as follows:

1. Reduction in Intrathoracic Pressure

During inhalation, the diaphragm contracts and moves downward, expanding the thoracic cavity. This increase in thoracic cavity volume lowers intrathoracic pressure, creating a low-pressure environment within the chest.

° Effect on Venous Return: the reduced intrathoracic pressure enhances the return of blood from the venae cavae to the heart. Consequently, a greater volume of blood flows into the atria and ventricles, stimulating the heart to pump more blood.

2. Inhibition of the Vagus Nerve

The vagus nerve, the primary component of the parasympathetic system, slows down heart rate. During inhalation, vagal activity is inhibited.

° Effect on Vagal Activity: lung expansion and increased venous return inhibit the vagus nerve, temporarily reducing its influence on the heart. As the vagus nerve normally slows heart rate, it’s inhibition during inhalation allows the heart to beat faster.

3. Activation of the Sympathetic Nervous System

Inhibition of the vagus nerve during inhalation creates space for an increase in sympathetic nervous system activity, which has the opposite effect, stimulating an acceleration of heart rate.

° Sympathetic Effect: the sympathetic system directly affects the sinoatrial node (the heart’s natural pacemaker) and cardiac muscle fibers, causing an in-crease in heart rate to meet the higher demand for oxygen and blood during inhalation.

4. Bainbridge Reflex

Another contributor to the increase in heart rate during inhalation is the Bainbridge reflex, also known as the atrial reflex. This reflex is triggered when the volume of venous blood returning to the heart increases, causing atrial distension.

° Effect on Stretch Receptors: stretch receptors in the atrial walls respond to the increased blood volume by stimulating the sympathetic nervous system. This reflex induces the heart to beat faster, pushing the accumulated blood from the heart to the rest of the body.

5. Increased Metabolic Demand

During inhalation, there is a higher demand for oxygen by the respiratory muscles and organs. The body responds to this need by accelerating heart rate to quickly deliver oxygen to the tissues.

° Effect on Oxygenation: the increase in heart rate allows for faster circulation of oxygen-rich blood, meeting the heightened metabolic demand induced by inhalation.

Mechanism of heart rate reduction during exhalation

During exhalation, heart rate tends to decrease due to a series of physiological mechanisms mediated by the autonomic nervous system, particularly the vagus nerve. This reduction in heart rate is a key aspect of the phenomenon known as Respiratory Sinus Arrhythmia (RSA), which reflects the dynamic interaction between respiration and the cardiovascular sys-tem14,16,20,22,24,28. Here’s how this process unfolds in detail:

1. Increase in Intrathoracic Pressure

During exhalation, the diaphragm relaxes and moves upward, reducing the thoracic cavity’s volume. This leads to an increase in intrathoracic pressure, meaning the pres-sure within the chest rises compared to inhalation.

° Effect on Venous Return: the increase in intrathoracic pressure reduces the flow of venous blood returning to the heart from the venae cavae. This decreases the volume of blood entering the atria and ventricles, lowering the need for an accelerated heart rate to pump blood.

2. Activation of the Vagus Nerve

The vagus nerve, part of the parasympathetic nervous system, plays a crucial role in reducing heart rate. During exhalation, vagal activity increases, exerting an inhibitory control on the heart.

° Parasympathetic Effect: the rise in vagal activity during exhalation acts di-rectly on the sinoatrial node (the heart’s natural pacemaker), slowing heart rate. This process is the primary driver of heart rate reduction during exhalation.

3. Reduction in Sympathetic Activity

During exhalation, there is also a decrease in sympathetic nervous system activity, which is responsible for increasing heart rate and triggering the “fight or flight” response.

° Effect on Sympathetic Activity: the reduction in sympathetic activity during exhalation decreases the stimulus that causes the heart to beat faster. As a result, the heart slows down.

4. Stabilisation of Metabolic Demand

During exhalation, the body does not need to pump oxygenated blood as rapidly as during inhalation. Exhalation is a more passive process than inhalation and requires less energy and oxygen.

° Effect on Oxygen Demand: since exhalation involves lower oxygen consumption and reduced metabolic demand, the heart can afford to slow down, reducing heart rate.

5. Mechanical Effect on the Heart and Vessels

The increase in intrathoracic pressure during exhalation slightly compresses large blood vessels, such as the vena cava, temporarily reducing blood flow to the heart.

° Effect on Cardiac Filling: with less blood returning to the heart during exha-lation, the heart does not need to beat as quickly to maintain adequate circulation. This reflexively reduces heart rate.

Synergy between vagus and sympathetic systems

The interaction between the vagus nerve (parasympathetic) and the sympathetic system during the respiratory cycle is fundamental for regulating heart rhythm. During exhalation, the predominance of vagal activity induces a relaxation response in the body, slowing the heartbeat and promoting a state of calm.

Integration between breathing and heartbeat: Respiratory Sinus Arrhythmia (RSA)

The constant cycle of heart rate variations during inhalation and exhalation is known as Respiratory Sinus Arrhythmia (RSA). This is a normal and healthy phenomenon, which is more pronounced in young and healthy individuals, while it tends to diminish with age, chronic stress, or illness. RSA is a positive indicator of good autonomic nervous system regulation, particularly the balance between the sympathetic and parasympathetic components. When this balance is optimal, heart rate variability (HRV) increases, which is associated with im-proved psychophysical well-being and a greater capacity to manage stress4,12-14,20.

What is cardio-respiratory coherence?

Cardio-respiratory coherence occurs when heart rhythm and breathing are synchronized in such a way as to create regular and harmonious waves in the HRV tracing. In practice, this means that heartbeats align perfectly with the respiratory cycle, reducing irregular variability and increasing the predictability of heart rhythm2,4,11,17,30.

What is cardio-respiratory resonance?

Cardio-respiratory resonance is a physiological state in which heart rate and respiratory rhythm synchronize to maximize heart rate variability (HRV) and amplitude, creating a harmonious and regular oscillation of cardiac waves. This optimal state occurs when the breath-ing rate aligns with a specific frequency, known as the “resonance frequency,” which varies slightly from person to person but generally falls around 5-7 breaths per minute4,17,30-32.










Mechanism of cardio-respiratory resonance

The concept of resonance is based on a physical principle where an oscillating system, such as heart rhythm, aligns with an external frequency, in this case, the respiratory rhythm. When the resonance frequency is reached, heart rate oscillations become wider and more regular, improving coherence between the respiratory and cardiovascular systems.

Synchronization process

1. Inhalation and Heart Rate Increase: during inhalation, the vagus nerve, part of the parasympathetic nervous system, reduces its activity, causing an increase in heart rate.

2. Exhalation and Heart Rate Decrease: during exhalation, vagal activity increases, slowing the heart rate.

3. Synchronization: when breathing occurs at the resonance frequency, the alternation of inhalation and exhalation produces regular HRV waves, creating a rhythmic and coherent pattern. This leads to high cardio-respiratory coherence, resulting in better autonomic nervous system balance.

Benefits of cardio-respiratory resonance4,11,17,33,34

1. HRV Optimisation: HRV is maximised during resonance, which is associated with greater stress resilience and improved cardiovascular health.

2. Stress and Anxiety Reduction: resonance state activates the parasympathetic system, promoting relaxation and reducing stress, anxiety, and cortisol levels.

3. Cognitive Function Improvement: cardio-respiratory resonance is linked to better focus, mental clarity, and cognitive performance.

4. Emotional Regulation Support: this practice stabilizes emotions, enhancing the ability to manage stress-induced emotional responses.

Application of cardio-respiratory resonance

Cardio-respiratory resonance can be achieved through controlled and mindful breathing techniques. The most common method is cardio-respiratory biofeedback, which uses devices to monitor heart and respiratory rates and guide breathing to reach the optimal resonance frequency.

In summary, cardio-respiratory resonance is a highly beneficial physiological state achieved by optimal synchronization between heart rhythm and breathing, leading to numerous positive effects on physical and mental well-being2,17,30,35.

Benefits of cardio-respiratory coherence3,4,11,34,35

1. Regulation of the Autonomic Nervous System: sympathetic-Parasympathetic Balance; Cardio-respiratory coherence fosters balance between the sympathetic and parasympathetic branches of the ANS, reducing stress and improving the body’s recovery capacity.

2. Improved HRV: high HRV is linked to better cardiovascular health, greater stress resilience, and enhanced adaptability to daily challenges.

3. Stress and Anxiety Reduction: regular practice of cardio-respiratory coherence activates the parasympathetic system, reducing cortisol (the stress hormone) and promoting a calm state.

4. Increased Emotional Awareness: it helps improve awareness of emotions and physiological responses, facilitating better emotional management.

5. Enhanced Cognitive Function: greater coherence can lead to better focus, memory, and mental clarity, improving cognitive performance.

6. Improved Sleep Quality: practicing coherence, especially before bedtime, can promote deeper, more restorative sleep and reduce insomnia.

Techniques to Achieve Cardio-Respiratory Coherence11,17,30,36,37

1. Diaphragmatic Breathing: inhaling deeply through the nose, expanding the diaphragm and filling the lungs with air, followed by a slow, controlled exhalation. This type of breathing promotes synchronization between the heart and lungs.

2. Box Breathing: a technique involving four equal phases: inhale for 4 seconds, hold the breath for 4 seconds, exhale for 4 seconds, and hold again for 4 seconds.

3. Coherent Breathing: breathing at a steady rhythm, typically around 6 breaths per mi-nute (0.1 Hz THM wave), optimizing synchronization between heart rhythm and breathing.

4. Biofeedback: devices like PPG Stress Flow and ANS Control (BioTekna - Italy) monitor HRV and provide visual and/or auditory feedback to help individuals maintain coherent breathing and heart rhythm.

Tools and technologies for practicing cardio-respiratory coherence4,11,30,38

1. Biofeedback Devices: tools for HRV diagnostics and monitoring, such as PPG Stress Flow, smartphone apps like BioTekna Plus, and wearable devices like ANS Control (BioTekna Italy), which provide diagnostic data and real-time HRV monitoring while guiding mindful breathing and cardio-respiratory biofeedback.

2. Software and Applications: programs such as BioTekna PLUS and the PPG Stress Flow APP offer guided and personalised breathing systems and HRV tracking, helping users monitor progress and maintain coherence.

Practical applications of cardio-respiratory coherence4,11,34,39,40

1. Stress Management: using cardio-respiratory coherence during acute stress or as a daily practice to prevent tension buildup.

2. Enhanced Athletic Performance: athletes use coherence to optimize focus, improve mental resilience, and support physical recovery.

3. Support in Psychological Therapy: integrated into treatments for anxiety, depression, PTSD, and other psychological conditions to improve emotional regulation.

4. Workplace Applications: implementation of coherence sessions to enhance employee well-being, reduce work-related stress, and boost productivity.

5. Education and Training: teaching coherence in schools and training programs to promote better stress management and emotional awareness among students and professionals.

Scientific evidence and research on cardio-respiratory coherence3,4,11,34,36

Numerous studies demonstrate the benefits of cardio-respiratory coherence:

• Stress Reduction: research shows that coherence significantly lowers cortisol and other stress biomarkers.

• Cardiovascular Health: studies highlight improved HRV and reduced blood pressure following regular coherence practices.

• Cognitive Function: evidence indicates that coherence can enhance cognitive per-formance, including memory and attention.

• Psychological Well-Being: findings support using coherence as an effective tool for managing anxiety and depression.

In summary

Cardio-respiratory coherence is a powerful physiological regulation technique that can be easily integrated into daily life to enhance physical and mental health. Through mindful breathing practices and the use of biofeedback tools such as ANS Control and the BioTekna PLUS app, it is possible to achieve autonomic balance, promoting overall well-being, stress resilience, and improved quality of life. Growing scientific evidence supports its effectiveness, making it a valuable practice in various therapeutic, educational, and professional contexts.

Effects of daily biofeedback practice for restoring cardio-respiratory coherence

Biofeedback for cardio-respiratory coherence is a technique aimed at synchronizing heart rhythm and breathing, improving physical and mental well-being. This approach is based on evidence that regular, deep breathing can positively influence the autonomic nervous system, reducing stress and enhancing emotional resilience4,11,30,31,34,36,39.

Effects in daily practice

1. Stress Reduction: one of the main benefits of BioFeedback for cardio-respiratory coherence is its ability to reduce stress and regulate the SNS and the HPA axis. Regular practice helps calm the sympathetic nervous system (which governs the “fight or flight” response) and strengthen the parasympathetic system, which promotes relaxation.

2. Improved Heart Rate Variability (HRV): cardio-respiratory coherence tends to enhance HRV, an indicator of good cardiovascular health and stress resilience. Higher HRV is associated with a greater ability to handle stressful situations and improved mental health.

3. Increased Body Awareness: through BioFeedback, individuals become more aware of their physiological responses, learning to better recognize and manage signs of tension or anxiety.

4. Enhanced Cognitive Performance: practicing cardio-respiratory coherence can improve focus, memory, and mental clarity. This effect is particularly useful in situations requiring prolonged attention or quick decision-making.

5. Emotional Regulation: bioFeedback for cardio-respiratory coherence helps develop greater emotional stability. Regular practice enables individuals to better manage negative emotions such as anger, anxiety, or sadness, reducing emotional reactivity.

6. Improved Sleep Quality: practicing BioFeedback, especially before bedtime, can promote deeper, more restorative sleep, reduce insomnia, and enhance overall sleep quality.

7. Long-Term Cardiovascular Health Benefits: over time, consistent cardio-respiratory coherence practice can help lower blood pressure, improve cardiac function, and reduce the risk of cardiovascular and other chronic diseases.

Integration into daily practice

• Short but Regular Sessions: even 5-minute sessions a day can provide significant benefits. Consistency is key. Ideally, 3 to 5 sessions of 5 minutes per day can yield substantial results in a short time. Recent studies have shown that approximately 300 sessions of 5-minute BioFeedback lead to long-lasting autonomic stability with excellent cardio-respiratory coherence (RSA).

• Use of BioFeedback Devices: specific tools such as BioTekna’s ANS Control with the BioTekna PLUS app can help remotely monitor, guide the practice, and assign tasks, making the process more precise and effective.

• Integration into Routine Moments: the practice can be incorporated into specific times of the day, such as upon waking, before a stressful meeting, before bedtime, or before meals.

In summary, the BioFeedback for cardio-respiratory coherence is a versatile practice that offers both physical and mental benefits, improving daily life quality and stress management.

Conclusions

This review on cardio-respiratory coherence (Respiratory Sinus Arrhythmia - RSA) highlights how this technique represents a promising non-pharmacological therapeutic intervention for restoring psychophysical well-being. The synchronization between heart rhythm and mindful breathing generates a state of coherence that brings significant mental and physical health benefits, including stress reduction, improved emotional regulation, enhanced cogni-tive and physical performance, and increased psychophysical resilience. From a physiological perspective, cardio-respiratory coherence directly impacts the autonomic nervous system (ANS), balancing sympathetic and parasympathetic activities, and optimizing heart rate vari-ability (HRV), a key indicator of cardiovascular health and adaptability to environmental stressors. Integrating BioFeedback with mindful breathing techniques is an effective strategy for inducing a state of cardio-respiratory coherence, facilitating the harmonisation of heart rate with respiratory rhythm. Scientific evidence suggests that cardio-respiratory coherence can be implemented in various clinical and preventive contexts, supporting the management of stress-related disorders, anxiety, and depression, while enhancing overall health and individual performance. The use of biofeedback tools, such as PPG devices and dedicated apps, allows for the monitoring and optimization of the practice, making it accessible and personalized. This makes cardio-respiratory coherence a versatile self-regulation practice that can be applied daily to promote lasting psychophysical well-being.

Device

The diagnostics and monitoring of cardio-respiratory BioFeedback (RSA) and heart rate variability (HRV) are typically conducted using medical devices such as the PPG Stress Flow (Bio-Tekna – Italy), an optoelectronic plethysmograph that measures blood volume variations for HRV analysis and biofeedback in the study of the autonomic nervous system. PPG Stress Flow devices are registered with the Italian Ministry of Health under the national classification of medical devices. These devices are CE-certified as non-invasive medical tools for diagnostic and monitoring purposes since 2004.

Conflicts of interest. The authors declare that there is no conflict of interest.

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