HRV Biofeedback for Improving Cognition in Older Adults: An Evidence-Based Tool

Neuropsychologist Sofía Fonseca explains how HRV biofeedback can improve cognition in older adults from a clinical perspective and presenting the available evidence.

Introduction

In the first part of this article we explored how heart rate variability (VFC) is linked to cognitive performance in old age. As we age, this variability tends to decrease, affecting not only physical health but also attention, memory and other critical mental functions. Faced with this scenario, key clinical questions arise: Can we intervene on HRV?; are there validated techniques to improve it?; can this impact cognition?

Below, we address HRV biofeedback, a noninvasive intervention that trains the autonomic nervous system through respiratory self-regulation. We will analyze how it works, what evidence supports its use in older adults and what applications it has in the context of cognitive stimulation and neuropsychological rehabilitation.

HRV biofeedback and cognitive functions

What is biofeedback and how does it work?

Biofeedback is a technique whose goal is for the individual to learn to voluntarily control responses of various of their own biological processes (Carrobles, 2016), by decreasing or increasing the likelihood of the occurrence of a physiological response, by associating it with some consequence (Moscoso, 1984).

This technique is an evidence-based practice, that is, it is based on evidence obtained from research to guide the provision of health services, and it has been tested and proven in research and clinical practice (Yucha & Montgomery, 2008).

The procedure consists of recording a specific physiological activity of a subject using electronic devices and specialized software. The system is programmed so that when the subject manages to evoke the desired physiological activity, they receive immediate and accurate feedback through auditory or visual stimuli. By associating this feedback with the physiological response, the subject learns to identify it and, through training, manages to modulate it voluntarily. It is essential that the information be presented in real time so that the subject can perceive the changes and learn to control them effectively (Yucha & Montgomery, 2008).

What types of biofeedback exist?

There are different types of biofeedback, depending on the physiological system being monitored, which are described below (Yucha & Montgomery, 2008):

• Electromyographic: measures the electrical activity of muscles.
• Temperature: records peripheral temperature.
• Electroencephalographic (EEG or neurofeedback): records brain electrical activity.
• Galvanic skin response: records changes in the skin’s electrical conductance, sensitive to sweat.
• Respiratory: records the rhythm and depth of breathing.
• Heart rate variability (VFC): focuses on the regulation of the heart rate rhythm.

In summary, biofeedback is a therapeutic tool that allows individuals to gain greater control over some of their physiological functions that normally operate automatically, through a learning process based on real-time feedback. Its usefulness has been supported by numerous scientific studies and its application has expanded to various clinical contexts such as stress management, anxiety, chronic pain, neurological disorders and cognitive optimization, among others.

HRV biofeedback

HRV biofeedback has been applied to various medical and psychiatric conditions such as asthma, anxiety, depression, chronic pain, among others (Moss, 2004). It consists of increasing heart rate variability by stimulating the baroreflex and respiratory sinus arrhythmia, through modulation of the breathing rate (Khazan, 2013).

• The baroreflex is a mechanism of the autonomic nervous system that helps maintain stable blood pressure; it operates through receptors located in the arteries (called baroreceptors) that detect changes in pressure and send signals to the brain to adjust heart rate and blood vessel diameter, thus promoting cardiovascular balance.
• Meanwhile, respiratory sinus arrhythmia (ARS) is a rhythmic fluctuation of heart rate that accompanies breathing, with inhalation increasing the heart rate and exhalation decreasing it (Khazan, 2013; Lehrer & Gevirtz, 2014).

To train HRV with this technique, it is necessary to monitor pulse and breathing at the same time, and the variations in the signals of these physiological functions are displayed on a computer screen; the person receiving the training uses the information provided by the computer to regulate these functions by modulating their breathing.

Sessions and personalization of HRV

It has been shown that 4 to 10 sessions of this type of training are required to achieve an increase in HRV (Yucha & Montgomery, 2008). The objective is to increase it by stimulating the baroreflex and respiratory sinus arrhythmia through modulation of the breathing rate (Khazan, 2013).

To personalize the treatment, in the first session heart rate variability (VFC) is measured and the person’s optimal breathing rate is identified. For this, two electrodes are placed: a photoplethysmograph on the index finger of the left hand to monitor pulse, and an electrode around the diaphragm to record breathing.

Subsequently, to identify the optimal breathing rate, the person is asked to breathe at different rhythms (6.5, 6, 5.5, 5 and 4.5 breaths per minute), for a couple of minutes each. With this information, the breathing rate that produces the greatest increase in HRV is identified, which indicates a better activation of the parasympathetic nervous system and a greater capacity for autonomic regulation. For the following sessions, the person learns to breathe at their optimal breathing rate, which will synchronize with their heart rate (Eddie et al., 2015; Moss, 2004; Theodore et al., 2002).

Currently there are no contraindications or risks associated with HRV biofeedback (Eddie et al., 2015); it has been used safely for the treatment of chronic obstructive pulmonary disease (Giardino et al., 2004), to improve cardiac function after myocardial infarction and in subjects with heart disease (Del Pozo et al., 2004; Nolan et al., 2005).

Evidence on the effects of biofeedback in improving cognitive functioning

HRV biofeedback has been shown to be effective in improving cognitive functions and emotional skills.

A study by Kim and colleagues showed that, after a HRV biofeedback training program, people with severe brain injury were able to increase their HRV and also showed improvements in emotional regulation, working memory, attention and problem solving. These results suggest that this intervention may be useful as a complementary tool in cognitive rehabilitation (Kim et al., 2013).

This intervention has also shown benefits in older adults, especially in reducing emotional symptoms and improving cognitive functions.

Challenges, limitations and ethical considerations

One of the main challenges in the application of biofeedback is accessibility and practitioner training.

In Latin America, the availability of specialized biofeedback equipment is limited, and costs are often high. In addition, the dissemination of knowledge about this technique is still somewhat scarce, which reduces its implementation in clinical settings. Despite this, there are efforts to promote its use, such as the work carried out by the Mexican Society of Bio and Neurofeedback, for example, which seeks to encourage professional training and application in Mexico.

Regarding methodological limitations, although there is a growing research base on biofeedback in general, studies that specifically evaluate the effects of HRV biofeedback on cognitive functioning remain limited, particularly when working with older adult populations, as this represents an additional challenge due to factors such as the presence of medical comorbidities, polypharmacy and heterogeneity in aging, which makes it somewhat complicated to carry out highly controlled research in the sample.

Finally, it is important to mention that ethical aspects must be considered when implementing biofeedback interventions. It is essential that biofeedback interventions be applied only by professionals who are properly trained and qualified in the health field. To ensure the safety and effectiveness of the treatment, it is necessary to request official professional credentials as well as certificates of training supported by recognized and reputable academic institutions or associations. This helps to avoid irresponsible practice or the actions of people without adequate preparation, protecting patients from possible harm and the risk of falling into the hands of people who might offer unfounded or unethical treatments.

Conclusion

In conclusion, heart rate variability (VFC) biofeedback represents a promising tool to improve both physical health and cognitive functioning, especially in aging. This is because HRV is a key indicator of physiological flexibility and of the autonomic nervous system’s ability to adapt to different situations, such as stress, functions that tend to deteriorate with age. Various studies have indicated that training HRV through biofeedback can promote emotional regulation, attention, executive functions and other cognitive skills commonly affected in older adults.

One advantage of this intervention is that it can be personalized, since the initial evaluation identifies the individual breathing rate that generates the greatest increase in HRV, which is associated with better activation of the parasympathetic nervous system and a greater capacity for autonomic self-regulation. In addition, to date no contraindications or risks associated with its use have been reported.

However, despite the encouraging preliminary results, more scientific evidence is needed based on methodologically sound designs and large samples to support its effectiveness in this population. To ensure safe and effective application, these interventions should be carried out by trained professionals with specific health training, adapting protocols to the particular characteristics of each person, especially considering comorbidities and conditions associated with advanced age.

Bibliography

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“This article has been translated. Link to the original article in Spanish:”
Biofeedback de la VFC para mejorar la cognición en adultos mayores: Una herramienta basada en evidencia