A pilot study investigating the relationship between heart rate variability and blood pressure in young adults at risk for cardiovascular disease

Background Cardiovascular disease is one of the leading causes of death globally with hypertension being a primary cause of premature death from this disease process. Individuals with a family history of cardiovascular disease and hypertension are at a greater risk for developing the same sequela. Autonomic cardiac control is important in the level of cardiac function. One intervention that is effective in improving cardiovascular function is heart rate variability biofeedback training. The purpose of our study was to determine the effectiveness of heart rate biofeedback training on HRV and blood pressure in individuals with a family history of cardiovascular disease. Methods Thirty-four participants (76.5% female, 22.7 ± 4.3 years) completed a baseline assessment and training using an established short-term HRV protocol followed by two weeks of at-home paced breathing employing a smartphone application. The participants were then reassessed in a biofeedback clinic. Results The participants physiological measures showed a significant increase in means between pre and post intervention of SDNN (t (32) = 2.177, p =.037) and TP, (t (32) = 2.327 p = .026). Correlation noted a medium effect on diastolic blood pressure and high frequency heart rate variability, F, r = .41, n =33, p < .05. A multiple regression with all predictor variables in the model found no significance with diastolic and systolic blood pressure. Conclusions The findings from this pilot study demonstrated that a two-week paced breathing intervention may assist in reducing heart rate and diastolic blood pressure while improving heart rate variability.

A randomized clinical trial to stimulate the cholinergic anti-inflammatory pathway in patients with moderate COVID-19-pneumonia using a slow-paced breathing technique

ImportanceVagus nerve stimulation via slow-paced breathing could serve as adjuvant therapeutic approach to reduce excessive inflammation in coronavirus disease 2019 (COVID-19) pneumonia.ObjectiveDoes a slow-paced breathing technique increasing vagal activity reduce Interleukin-6 (IL-6) in patients hospitalized with moderate COVID-19 pneumonia compared to standard care?DesignSingle-center randomized controlled clinical trial with enrolment from February 23rd 2021 through June 17th 2021 and follow-up until July 22nd 2021.SettingWard for infectious diseases and temporary COVID-19 ward, Ulm University Hospital, GermanyParticipantsConsecutive sample of patients hospitalized with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and moderate COVID-19 pneumonia (primary diagnosis). Of 131 patients screened, 48 patients were randomized and 46 patients analyzed (N=23 per group).InterventionsSlow-paced 20-minute breathing exercise three times a day with six breaths per minute (inhale-to-exhale ratio 4:6).Main outcomes and measuresDifferences between intervention and control group in IL-6 calculated using multilevel mixed-effect linear regression models with random slope including the covariates relevant comorbidities, COVID-19 medication, and age.ResultsMean age 57 years±13 years, N= 28 (60%) male, N=30 (65%) with relevant comorbidities. The model including group by time interaction revealed a significantly lower trajectory of IL-6 in the intervention group compared to the control group (effect size Cohens f2=0.11, LR-test p=.040) in the intention-to-treat sample, confirmed by treatment-per-protocol analysis (f2=0.15, LR-test p=.022).Exploratory analysis using the median split of practice time to predict IL-6 of the next morning indicated a dose-response relationship with beneficial effects of practice time above 45 minutes a day.Three patients in each group were admitted at ICU, one died. Oxygen saturation increased during slow-paced breathing (from 95.1%±2.1% to 95.4%±1.6%, p=0.006).Conclusion and relevancePatients practicing slow-paced breathing had significantly lower IL-6 values than controls without relevant side effects. Further trials should evaluate clinical outcomes as well as an earlier start of the intervention, i.e., at symptom onset. This would offer an access to a therapy option not only for high-income, but also for low- and middle-income countries.Trial registrationGerman register of clinical trials (ID: DRKS00023971) https://www.drks.de, Universal Trial Number (UTN) U1111-1263-8658;Key pointsQuestionCan slow-paced breathing reduce Interleukin-6 (IL-6) in hospitalized patients with moderate coronavirus disease 2019 (COVID-19) pneumonia?FindingsSingle-center randomized controlled clinical trial including 46 patients hospitalized with moderate COVID-19 pneumonia. Compared to controls, IL-6 values were significantly lower (small-to-medium effect sizes) in patients who were instructed to practice six breaths per minute for 20 minutes three times a day. More minutes of slow-paced breathing were significantly correlated with lower IL-6 values the next morning.MeaningSlow-paced breathing could be a safe and feasible adjuvant therapeutic approach in moderate COVID-19 pneumonia.

Single Slow-Paced Breathing Session at Six Cycles per Minute: Investigation of Dose-Response Relationship on Cardiac Vagal Activity

The practice of slow-paced breathing (SPB) has been linked to a range of positive outcomes, such as decreasing symptoms of depression, anxiety, and stress, as well as increasing well-being. Among the suggested mechanisms of action, SPB has been shown to increase cardiac vagal activity (CVA). The present study aimed to investigate whether there is a dose-response relationship modulating the effects of SPB on CVA. A total of 59 participants were involved in this study. In a within-subject design, participants attended the lab five times, and realized SPB at six cycles per minute with different durations (5, 10, 15, and 20 min), as well as a control condition without SPB. CVA was indexed via the root mean square of successive differences (RMSSD). During SPB, findings showed an increase in RMSSD in all conditions compared to the control condition. However, no differences were found in RMSSD among the different session durations, during SPB or during the resting measurement completed immediately after SPB. Noteworthily, session duration showed an influence on the spontaneous respiratory frequency in the resting measurement occurring immediately after SPB. Specifically, respiratory frequency appears to decrease with session duration, thus potentially contributing to additional relaxing effects.

Effect of device-guided paced breathing of biofeedback on blood pressure, stress and anxiety levels in hypertensives

The present study aimed to evaluate the influence of cardiac coherence through Biofeedback Therapy (BT) with paced breathing on blood pressure, stress and anxiety levels in individuals with essential arterial hypertension. The participants underwent 8 sessions of paced breathing guided by biofeedback visual therapy for 20 minutes, in which they were evaluated through clinical assessment, Hamilton Anxiety Rating Scale, Perceived Stress Scale and cardiovascular variables. Comparisons of means were performed using the paired and unpaired Student's t-test. Statistically significant correlations were considered when p ≤ 0.05 with a 95% confidence interval. The effect size (Cohen's d) and common language effect size were calculated to assess the effect of such therapy. Sixteen patients with mean age of 57.3 ± 14 years old participated in this study. Comparisons between mean initial and final systolic blood pressure levels (SBP) in women (p = 0.007; Cohen's d = 0.50), pre- and post-training heart rate (p = 0.02; Cohen's d = 0.60) and anxiety levels (p = 0.01; Cohen's d = 1.04) were significant. Comparisons between pre- and post-training SBP (p = 0.006; Cohen's d = 0.81) and pre- and post-training anxiety levels (p = 0.04; Cohen's d = 0.32) were significant among males. In conclusion, paced breathing training with biofeedback therapy can be promising to reduce anxiety levels in individuals with essential arterial hypertension.

Slow-Paced Breathing: Influence of Inhalation/Exhalation Ratio and of Respiratory Pauses on Cardiac Vagal Activity

Slow-paced breathing has been shown to enhance the self-regulation abilities of athletes via its influence on cardiac vagal activity. However, the role of certain respiratory parameters (i.e., inhalation/exhalation ratio and presence of a respiratory pause between respiratory phases) still needs to be clarified. The aim of this experiment was to investigate the influence of these respiratory parameters on the effects of slow-paced breathing on cardiac vagal activity. A total of 64 athletes (27 female; Mage = 22, age range = 18–30 years old) participated in a within-subject experimental design. Participants performed six breathing conditions within one session, with a 5 min washout period between each condition. Each condition lasted 5 min, with 30 respiratory cycles, and each respiratory cycle lasted 10 s (six cycles per minute), with inhalation/exhalation ratios of 0.8, 1.0, 1.2; and with or without respiratory pauses (0.4 s) between respiratory phases. Results indicated that the root mean square of successive differences (RMSSD), a marker of cardiac vagal activity, was higher when exhalation was longer than inhalation. The presence of a brief (0.4 s) post-inhalation and post-exhalation respiratory pause did not further influence RMSSD. Athletes practicing slow-paced breathing are recommended to use an inhalation/exhalation ratio in which the exhalation phase is longer than the inhalation phase.

Different Effects of Four Yogic Breathing Techniques on Mindfulness, Stress, and Well-being

Yogic breathing techniques are fundamental to the physical and mental practice of yoga. They are closely connected to meditation, which involves the observation of breath. There are many yogic techniques based on the active regulation of the breath. Breathing practices influence many processes in the body, e.g. heart rate variability, and the mind, e.g. relaxation and stress, through their impact on the autonomic nervous system. This study intended to investigate differential effects of four yogic breathing techniques: (1) <em>ujjayi</em>—relaxation through slowing down the breath, (2) paced breathing—enhancement of concentration by following a precise protocol of slowdown breathing, (3) <em>kapalabhati</em>—raising wakefulness by mild hyperventilation, and (4) alternate nostril breathing—balancing the autonomic nervous system by alternating breath between the two nostrils. This study was conducted on 36 participants, who learned each technique within two weeks of an eight-week program and practiced them daily. After each technique, mindfulness, perceived stress, and physical well-being were assessed based on questionnaires. Ujjayi breathing, showed a relaxing effect, reduced stress, increased peacefulness, and the feeling of being at ease/leisure. Paced breathing resulted in a greater awareness of inner experiences. Kapalabhati showed a significant increase in vitality and joy of life, and alternate nostril breathing showed no hypothesis-compliant changes. The findings of this study suggest several beneficial and differential effects of these breathing techniques; therefore, they could be employed as tools for self-regulation in therapeutic contexts.

Emotional Intelligence Training: Influence of a Brief Slow-Paced Breathing Exercise on Psychophysiological Variables Linked to Emotion Regulation

Designing emotional intelligence training programs requires first testing the effectiveness of techniques targeting its main dimensions. The aim of this study was to investigate the effects of a brief slow-paced breathing (SPB) exercise on psychophysiological variables linked to emotion regulation, namely cardiac vagal activity (CVA), as well as perceived stress intensity, emotional arousal, and emotional valence. A total of 61 participants completed a 5-min SPB exercise and a control condition of a 5-min rest measurement. CVA was indexed with the root mean square of successive differences (RMSSD). Participants were also asked to rate their perceived stress intensity, emotional arousal, and emotional valence. Results showed that CVA was higher during SPB in comparison to the control condition. Contrary to our hypothesis, perceived stress intensity and emotional arousal increased after SPB, and perceived emotional valence was less positive after SPB. This could be explained by experiencing dyspnea (i.e., breathing discomfort), and the need to get acclimatized to SPB. Consequently, we may conclude that although physiological benefits of SPB on CVA are immediate, training may be required in order to perceive psychological benefits.