Heart Rate Variability, Flow, Mood and Mental Stress During Yoga Practices in Yoga Practitioners, Non-yoga Practitioners and People with Metabolic Syndrome

Improved Sympathetic Activity With Short-Term Effects of Yoga in Young Adults

The purpose of this study was to clarify the heart rate variability (HRV) transition after a single yoga program. Participants were 22 females who were healthy university students and had never practiced yoga before. They practiced yoga while recording their HRV. Heart rate (HR), high frequency (HF; 0.15-0.4 Hz) as parasympathetic and low frequency (LF; 0.04-0.15 Hz) components were extracted, and then the LF/HF ratio as sympathetic and normalized units of HF HFnu = HF/(LF + HF) as parasympathetic modulation in autonomic activity were calculated. HR and HRV indices after yoga were divided into four 5-minute periods (after 5, 10, 15, and 20 minutes) and compared before yoga. HR and LF/HF at all periods after yoga were significantly lower than before yoga (P < .01, all). HF after yoga was not significantly changed, but HFnu after 5, 10, and 15 minutes was significantly higher than before yoga (P < .01, <.01, and =.02, respectively). The short-term effects of yoga on HRV implied a decrease in sympathetic modulation and a relative increase in parasympathetic modulation. Therefore, yoga may be used as a fast-acting alternative therapy to significantly improve sympathetic activity.

Enteric neuropathy and the vagus nerve: Therapeutic implications

Enteric neuropathies are characterized by abnormalities of gut innervation, which includes the enteric nervous system, inducing severe gut dysmotility among other dysfunctions. Most of the gastrointestinal tract is innervated by the vagus nerve, the efferent branches of which have close interconnections with the enteric nervous system and whose afferents are distributed throughout the different layers of the digestive wall. The vagus nerve is a key element of the autonomic nervous system, involved in the stress response, at the interface of the microbiota-gut-brain axis, has anti-inflammatory and prokinetic properties, modulates intestinal permeability, and has a significant capacity of plasticity and regeneration. Targeting these properties of the vagus nerve, with vagus nerve stimulation (or non-stimulation/ pharmacological methods), could be of interest in the therapeutic management of enteric neuropathies.

Link between Yoga and Heart Rate Variability: Can Yoga Enhance the Cardiac Resonance

Cardiac resonance is a complicated phenomenon involving the coordinated oscillations of numerous circulatory system components, such as electrical activity, contraction and relaxation, and blood flow. It is critical for the normal functioning of the heart and for maintaining blood flow throughout the body. Cardiac resonance is defined as a series of tiny waves produced by the heartbeat and overlaid on flow data and airway pressures. A variety of technologies, including cardiac magnetic resonance (CMR) imaging, can be used to identify these waves. CMR is a strong noninvasive method for seeing and quantifying heart anatomy and function in great detail. CMR can be used to assess cardiac resonance in both healthy and heart disease patients. A regular and coordinated pattern of oscillations characterizes cardiac resonance in healthy persons. In patients with heart illness, however, cardiac resonance can be interrupted, resulting in diminished cardiac function and decreased blood flow. The intricate role of cardiac resonance in cardiac health and disease is continuously being studied by researchers. However, it is obvious that cardiac resonance is an exciting area of research that has the potential to change the way to identify and treat heart illness. Yoga is a mind-body practice that has been demonstrated to have numerous cardiovascular health advantages, such as improved heart function, reduced inflammation, and lower blood pressure. Yoga is hypothesized to promote cardiac resonance by encouraging coordinated oscillations of numerous cardiovascular system components. Various researches have shown buoyant results such as yoga can be helpful in improving heart rate variability, cardiac resonance and reducing arterial stiffness. Stress can disrupt cardiac resonance and increase the risk of heart disease. More research is needed to completely understand the mechanisms that impact cardiac resonance and the long-term advantages of yoga for heart health.

Stress Response Pattern of Heart Rate Variability in Patients with Functional Somatic Syndromes

Functional somatic syndromes (FSSs) represent a clinically important group of disorders that are often stress-related. Their autonomic pathophysiology, including reduced heart rate variability (HRV), has been reported. However, the response pattern to mental stress and recovery in FSSs remains unclear. Thus, we aimed to clarify the pattern of autonomic stress response and recovery to mental arithmetic stress in patients with FSS compared to that in healthy controls. This cross-sectional study included 79 patients with FSS who visited the Department of Psychosomatic Medicine at a university hospital in Japan and 39 healthy controls. Following a mood questionnaire and obtaining epidemiologic information, HRV was measured during three periods (5 min each): relaxation baseline resting, stress (mental arithmetic task), and post-stress recovery period. The HRV analysis included inter-beat interval, low frequency power, and high frequency power. Compared to healthy controls, patients with FSS exhibited significantly higher scores on the mood questionnaire, prolonged duration of illness, and decreased functionality in daily activities. While the healthy control group showed a pronounced stress response pattern with a significant decrease in vagal HRV and recovery, the FSS group showed a "flat" vagal stress response pattern, and the HRV in the FSS group was lower at relaxation baseline, remained low during the stress, and did not change post stress. Patients with severe FSS exhibit an altered stress response pattern. Our results could provide significant clues for the diagnosis and treatment of such patients, as well as useful insights into the relationship between stress and illness.

Short-Term Heart Rate Variability in Metabolic Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

Our aim was to determine the differences in short-term heart rate variability (HRV) between patients with metabolic syndrome (MS) and healthy controls.

METHODS

We searched electronic databases for primary works with short-term HRV recordings (≤30 min) that made comparisons between individuals with MS versus healthy controls. This systematic review and meta-analysis (MA) was performed according to PRISMA guidelines and registered at PROSPERO (CRD42022358975).

RESULTS

Twenty-eight articles were included in the qualitative synthesis and nineteen met the criteria for the MA. Patients with MS showed decreased SDNN (-0.36 [-0.44, -0.28], p < 0.001), rMSSD (-7.59 [-9.98, -5.19], p < 0.001), HF (-0.36 [-0.51, -0.20], p < 0.00001) and LF (-0.24 [-0.38, -0.1], p = 0.001). In subsequent subanalyses, we found a decrease in SDNN (-0.99 (-1.45, -0.52], p < 0.001), rMSSD (-10.18 [-16.85, -3.52], p < 0.01) and HF (-1.04 [-1.97, -0.1] p < 0.05) in women. In men, only LF showed a significant lower value (-0.26 [-0.5, -0.02], p < 0.05). We could not perform MA for non-linear variables.

CONCLUSIONS

Patients with MS showed changes in time-domain analyses, with lower values in SDNN and rMSSD. Regarding frequency-domain analyses, MS patients showed a decrease in HF and LF When sex was used as a grouping variable, the MA was only possible in one of both sexes (men or women) in rMSSD and LF/HF. Lastly, when data for both men and women were available, subanalyses showed a different behavior compared to mixed analyses for SDNN, HF and LF, which might point towards a different impact of MS in men and women.

Perceived Stress, Resilience, and Wellbeing in Seasoned Isha Yoga Practitioners Compared to Matched Controls During the COVID-19 Pandemic

Background

Yoga practices, including breathing, meditation, and posture protocols (asanas), have been shown to facilitate physical and mental wellbeing.

Methods

Seasoned yoga practitioners were recruited from the Isha Foundation. Recruitment of the comparison group was achieved using snowball sampling and were not yoga practitioners. Participants in the non-yoga group were randomized to a 3-min Isha practice or a comparator group asked to perform 15-min of daily reading. Participants completed a series of web-based surveys (REDCap) at baseline, 6, and 12 weeks. These surveys include validated scales and objective questions on COVID-19 infection and medical history. The validated questionnaires assess for: perceived stress (PSS), mood states [anxiety and depression (PHQ-4), joy (DPES-Joy subscale)], mindfulness attention and awareness (MAAS), resilience (BRS), mental wellbeing (WEMWBS) and recovery from traumatic event (PTGI). Weekly activity diaries were employed as a tool for collecting compliance information from study participants. Perceived stress scale scores were identified as primary outcome for this study.

Findings

The median Perceived Stress Scale (PSS) score for the yoga practitioners compared to the active and placebo comparators was significantly lower at all time-points: baseline: 11 [IQR 7–15] vs. 16 [IQR 12–21] in both the active and placebo comparators (p &lt; 0.0001); 6 weeks: 9 [IQR 6–13] vs. 12 [IQR 8–17] in the active comparator and 14 [IQR 9–18] in the placebo comparator (p &lt; 0.0001); and 12 weeks: 9 [IQR 5–13] vs. 11.5 [IQR 8–16] in the active comparators and 13 [IQR 8–17] in the placebo comparator (p &lt; 0.0001). Among the randomized participants that were compliant for the full 12 weeks, the active comparators had significantly lower median PSS scores than the placebo comparators 12 weeks [10 (IQR 5–14) vs. 13 (IQR 8–17), p = 0.017]. Further, yoga practitioners had significantly lower anxiety at all three-time points (p &lt; 0.0001), lower depression at baseline and 6 weeks (p &lt; 0.0003), and significantly higher wellbeing (p &lt; 0.0001) and joy (p &lt; 0.0001) at all three-time points, compared to the active and placebo comparator groups.

Interpretation

The lower levels of stress, anxiety, depression, and higher level of wellbeing and joy seen in the yoga practitioners compared to the active and placebo comparators illustrate the impact of regular yoga practices on mental health even during the pandemic.

Trial Registration

ClinicalTrials.gov, identifier: NCT 04498442.

The Psychophysiological Profile and Cardiac Autonomic Reactivity in Long-Term Female Yoga Practitioners: A Comparison with Runners and Sedentary Individuals

Yoga practice, a means of stress management, has been reported to optimize psychophysiological health; however, its underlying mechanisms remain unclear. The purpose of the present study was to examine the psychophysiological profile and cardiac autonomic reactivity in long-term yoga practitioners and compare them to runners and sedentary individuals. Psychological health and aerobic fitness level were evaluated using self-reported questionnaires and a 3-min step test. Blood pressure (BP), heart rate (HR), respiration rate (RR), and heart rate variability (HRV) parameters were recorded at rest, as well as during and following psychological stress, which was elicited by the Stroop color and word test and the mental arithmetic task. The yoga group demonstrated a lower RR (10.35 ± 2.13 bpm) as compared to the other two groups, and a lower HR (66.60 ± 7.55 bpm) and diastolic BP (67.75 ± 8.38 mmHg) at rest when compared to the sedentary group (all p < 0.05). HRV parameters following mental stress returned to the baseline in yoga and running groups, but not in the sedentary group. The anxiety level in the running group was significantly lower than that in the sedentary group (p < 0.05). These findings suggested that yoga practitioners may have a greater homeostatic capacity and autonomic resilience than do sedentary individuals.

A Scoping Review of Flow Research

Flow is a gratifying state of deep involvement and absorption that individuals report when facing a challenging activity and they perceive adequate abilities to cope with it (EFRN, 2014). The flow concept was introduced by Csikszentmihalyi in 1975, and interest in flow research is growing. However, to our best knowledge, no scoping review exists that takes a systematic look at studies on flow which were published between the years 2000 and 2016. Overall, 252 studies have been included in this review. Our review (1) provides a framework to cluster flow research, (2) gives a systematic overview about existing studies and their findings, and (3) provides an overview about implications for future research. The provided framework consists of three levels of flow research. In the first “Individual” level are the categories for personality, motivation, physiology, emotion, cognition, and behavior. The second “Contextual” level contains the categories for contextual and interindividual factors and the third “Cultural” level contains cultural factors that relate to flow. Using our framework, we systematically present the findings for each category. While flow research has made progress in understanding flow, in the future, more experimental and longitudinal studies are needed to gain deeper insights into the causal structure of flow and its antecedents and consequences.

Cortical and autonomic responses during staged Taoist meditation: Two distinct meditation strategies

Meditation is a consciousness state associated with specific physiological and neural correlates. Numerous investigations of these correlates reported controversial results which prevented a consistent depiction of the underlying neurophysiological processes. Here we investigated the dynamics of multiple neurophysiological indicators during a staged meditation session. We measured the physiological changes at rest and during the guided Taoist meditation in experienced meditators and naive subjects. We recorded EEG, respiration, galvanic skin response, and photoplethysmography. All subjects followed the same instructions split into 16 stages. In the experienced meditators group we identified two subgroups with different physiological markers dynamics. One subgroup showed several signs of general relaxation evident from the changes in heart rate variability, respiratory rate, and EEG rhythmic activity. The other subgroup exhibited mind concentration patterns primarily noticeable in the EEG recordings while no autonomic responses occurred. The duration and type of previous meditation experience or any baseline indicators we measured did not explain the segregation of the meditators into these two groups. These results suggest that two distinct meditation strategies could be used by experienced meditators, which partly explains the inconsistent results reported in the earlier studies evaluating meditation effects. Our findings are also relevant to the development of the high-end biofeedback systems.

The immediate and durable effects of yoga and physical fitness exercises on stress

This study aimed to examine the effects of yoga and physical fitness exercises on stress and the underlying mechanisms. Participants: Healthy undergraduates from four yoga and four fitness classes participated in Study 1 (n = 191) and Study 2 (n = 143), respectively (in 2017 Fall). Methods: Study 1 evaluated the immediate effect (a 60-minute practice) while Study 2 evaluated the durable effect (a 12-week intervention). Results: Results showed that immediate stress reduction was more salient in the yoga group than that in the fitness group in Study 1. Yoga group had a greater increase in mindfulness, which predicted stress reduction. Similar observations were made in Study 2 showing the durable effect of yoga on stress reduction through mindfulness. Conclusions: Yoga intervention is better than fitness exercises in helping undergraduates cultivate mindfulness and reduce stress. These findings may guide future interventions in stress management in college students.

Comparing the Psychological Effects of Meditation- and Breathing-Focused Yoga Practice in Undergraduate Students

Objectives

The present study aimed to compare the psychological effects of meditation- and breathing-focused yoga practice in undergraduate students.

Methods

A 12-weeks yoga intervention was conducted among a group of undergraduate students enrolled in four yoga classes at an academically prestigious university in Beijing, China. Four classes were randomized to meditation-focused yoga or breathing-focused yoga. A total of 86 participants finished surveys before and after the 12-weeks intervention, measuring work intention, mindfulness, and perceived stress. The repeated-measure multivariate analysis of covariance (MANCOVA) followed by univariate analyses were conducted to examine the differences in work intention, mindfulness, and stress between the two yoga intervention groups over the semester, after controlling for age and gender.

Results

The repeated-measure MANCOVA revealed significant group differences with a median effect size [Wilks' lambda, Λ = 0.90, F(3, 80) = 3.10, p = 0.031, η² = 0.104]. Subsequent univariate analyses showed that students in the breathing-focused yoga group had significant higher work intentions [F _{(1, 82)} = 5.22; p = 0.025; η² _p = 0.060] and mindfulness [F _{(1, 82)} = 6.33; p = 0.014; η² _p = 0.072] but marginally lower stress [F _{(1, 82)} = 4.20; p = 0.044; η² _p = 0.049] than students in the meditation-focused yoga group.

Conclusion

Yoga practice with a focus on breathing is more effective than that with a focus on meditation for undergraduates to retain energy for work, keep attention and awareness, and reduce stress.

Changes in Heart Rate Variability after Yoga are Dependent on Heart Rate Variability at Baseline and during Yoga: A Study Showing Autonomic Normalization Effect in Yoga-Naïve and Experienced Subjects

Background:

Yoga therapy is widely applied to the maintenance of health and to treatment of various illnesses. Previous researches indicate the involvement of autonomic control in its effects, although the general agreement has not been reached regarding the acute modulation of autonomic function.

Aim:

The present study aimed at revealing the acute effect of yoga on the autonomic activity using heart rate variability (HRV) measurement.

Methods:

Twenty-seven healthy controls participated in the present study. Fifteen of them (39.5 ± 8.5 years old) were naïve and 12 (45.1 ± 7.0 years old) were experienced in yoga. Yoga skills included breath awareness, two types of asana, and two types of pranayama. HRV was measured at the baseline, during yoga, and at the resting state after yoga.

Results:

In both yoga-naïve and experienced participants, the changes in low-frequency (LF) component of HRV and its ratio to high-frequency (HF) component (LF/HF) after yoga were found to be correlated negatively with the baseline data. The changes in LF after yoga were also correlated with LF during yoga. The changes in HF as well as the raw HRV data after yoga were not related to the baseline HRV or the HRV during yoga.

Conclusion:

The results indicate that yoga leads to an increase in LF when LF is low and leads to a decrease in LF when it is high at the baseline. This normalization of LF is dependent on the autonomic modulation during yoga and may underlie the clinical effectiveness of yoga therapy both in yoga-naïve and experienced subjects.

Getting Specific about Emotion and Self-Inflicted Injury: An Examination Across Emotion Processes in Borderline Personality Disorder

This study aimed to examine which specific emotion processes influence self-inflicted injury: basal respiratory sinus arrhythmia, baseline negative emotional intensity, emotional reactivity, or emotion regulation deficits. Self-injuring individuals with borderline personality disorder (N = 22) reported their lifetime self-injury frequency. Basal respiratory sinus arrhythmia and baseline skin conductance responses measurements were collected. Participants then either reacted as they usually would (i.e., emotional reactivity), or utilized mindfulness- or distraction-based strategies (i.e., emotion regulation), in response to negative images while self-reported negative emotion and skin conductance were monitored. Higher basal respiratory sinus arrhythmia and baseline emotional intensity predicted higher lifetime self-injury frequency. Chronic, resting emotion processes may be more important targets for reducing self-injury compared to labile, acute emotion processes.

How does yoga reduce stress? Embodied cognition and emotion highlight the influence of the musculoskeletal system

Yoga is an increasingly popular activity, perhaps because of its association with stress reduction and relaxation - an association that is generally supported by empirical evidence. Understanding of the mediating variables is, however, limited. Given that, the purpose of this paper is to present a theoretical perspective that encourages systematic research regarding the relationship between yoga, stress, and musculoskeletal activity. This embodied perspective parallels popular interest in the mind-body connection and emphasizes the influence of body position on thinking as well as emotion. Those influences take on added meaning in the context of the Cognitive Appraisal Theory and the Biopsychosocial Model of Challenge and Threat. Investigations of embodied cognition suggest that yoga may reduce stress by affecting the way individuals appraise stressors. The combination of body position and common components of yoga practice may also contribute to that effect, particularly when considering thoughts about the self and feelings of confidence. Findings regarding embodied emotion make a similar contribution to understanding the implications of previous research findings and common yoga practices. Considering yoga and stress from an embodied perspective also highlights the role of the musculoskeletal system in the stress process, leading to the question of whether yoga influences stress by directly influencing the musculoskeletal system, indirectly by influencing awareness of that system, or through a combination of the two. Those questions, in turn, highlight the importance of expanding investigations of psychological processes, body position, musculoskeletal activity during yoga, and the interactions between those variables.

A PHONOCARDIOGRAM-BASED NOISE-ROBUST REAL-TIME HEART RATE MONITORING ALGORITHM FOR OUTPATIENTS DURING NORMAL ACTIVITIES

For outpatients who need continuous monitoring of heart rate (HR) variation, it is important that HR can be monitored during normal activities such as speaking and walking. In this study, a noise-robust real-time HR monitoring algorithm based on phonocardiogram (PCG) signals is proposed. PCG signals were recorded using an electronic stethoscope; electrocardiogram (ECG) signals were recorded simultaneously with HR references. The proposed algorithm consisted of pre-processing, peak/nonpeak classification, voice noise processing, walking noise processing, and HR calculation. The performance of the algorithm was evaluated using PCG/ECG signals from 11 healthy participants. For comparison, the absolute errors between manually extracted ECG-based HR values and automatically calculated PCG-based HR values were calculated for the proposed algorithm and the comparison algorithm in two different test protocols. Experimental results showed that the average absolute errors of the proposed algorithm were 72.03%, 22.92%, and 36.39% of the values of the comparison algorithm for resting-state, speaking-state, and walking-state data, respectively, in protocol-1. In protocol-2, the average absolute error was 36.99% of that of the comparison algorithm. A total of 1102 cases in protocol-1 and 783 in protocol-2 had an absolute error [Formula: see text] beats per minute (BPM) using the comparison algorithm and an absolute error [Formula: see text] BPM using the proposed algorithm. On the basis of these results, we anticipate that the proposed algorithm can potentially improve the performance of continuous real-time HR monitoring during activities of normal life, thereby improving the safety of outpatients with cardiovascular diseases.

The Vagus Nerve in the Neuro-Immune Axis: Implications in the Pathology of the Gastrointestinal Tract

The vagus nerve (VN) is the longest nerve of the organism and a major component of the parasympathetic nervous system which constitutes the autonomic nervous system (ANS), with the sympathetic nervous system. There is classically an equilibrium between the sympathetic and parasympathetic nervous systems which is responsible for the maintenance of homeostasis. An imbalance of the ANS is observed in various pathologic conditions. The VN, a mixed nerve with 4/5 afferent and 1/5 efferent fibers, is a key component of the neuro-immune and brain-gut axes through a bidirectional communication between the brain and the gastrointestinal (GI) tract. A dual anti-inflammatory role of the VN is observed using either vagal afferents, targeting the hypothalamic–pituitary–adrenal axis, or vagal efferents, targeting the cholinergic anti-inflammatory pathway. The sympathetic nervous system and the VN act in synergy, through the splenic nerve, to inhibit the release of tumor necrosis factor-alpha (TNFα) by macrophages of the peripheral tissues and the spleen. Because of its anti-inflammatory effect, the VN is a therapeutic target in the treatment of chronic inflammatory disorders where TNFα is a key component. In this review, we will focus on the anti-inflammatory role of the VN in inflammatory bowel diseases (IBD). The anti-inflammatory properties of the VN could be targeted pharmacologically, with enteral nutrition, by VN stimulation (VNS), with complementary medicines or by physical exercise. VNS is one of the alternative treatments for drug resistant epilepsy and depression and one might think that VNS could be used as a non-drug therapy to treat inflammatory disorders of the GI tract, such as IBD, irritable bowel syndrome, and postoperative ileus, which are all characterized by a blunted autonomic balance with a decreased vagal tone.

Vagus nerve stimulation: a new promising therapeutic tool in inflammatory bowel disease

Inflammatory bowel disease (IBD), that is Crohn's disease (CD) and ulcerative colitis, affects about 1.5 million persons in the USA and 2.2 million in Europe. The pathophysiology of IBD involves immunological, genetic and environmental factors. The treatment is medico-surgical but suspensive. Anti-TNFα agents have revolutionized the treatment of IBD but have side effects. In addition, a non-negligible percentage of patients with IBD stop or take episodically their treatment. Consequently, a nondrug therapy targeting TNFα through a physiological pathway, devoid of major side effects and with a good cost-effectiveness ratio, would be of interest. The vagus nerve has dual anti-inflammatory properties through its afferent (i.e. hypothalamic-pituitary-adrenal axis) and efferent (i.e. the anti-TNFα effect of the cholinergic anti-inflammatory pathway) fibres. We have shown that there is an inverse relationship between vagal tone and plasma TNFα level in patients with CD, and have reported, for the first time, that chronic vagus nerve stimulation has anti-inflammatory properties in a rat model of colitis and in a pilot study performed in seven patients with moderate CD. Two of these patients failed to improve after 3 months of vagus nerve stimulation but five were in deep remission (clinical, biological and endoscopic) at 6 months of follow-up and vagal tone was restored. No major side effects were observed. Thus, vagus nerve stimulation provides a new therapeutic option in the treatment of CD.

Incorporation of a Stress Reducing Mobile App in the Care of Patients With Type 2 Diabetes: A Prospective Study

Background

Severe and sustained emotional stress creates a physiological burden through increased sympathetic activity and higher energy demand. This may lead to increased oxidative stress and development of the metabolic syndrome. Emotional stress has been shown to contribute to the onset, progression, and control of type 2 diabetes (T2D). Stress management and biofeedback assisted relaxation have been shown to improve glycemic control. Use of a mobile app for stress management may enhance the scalability of such an approach.

Objective

The aim of this study was to assess the effect of using a mobile app of biofeedback-assisted relaxation on weight, blood pressure (BP), and glycemic measures of patients with T2D.

Methods

Adult patients with T2D and inadequate glycemic control (hemoglobin A1c [HbA1c]>7.5%) were recruited from the outpatient diabetes clinic. Baseline weight, BP, HbA1c, fasting plasma glucose (FPG), triglycerides (TG), and 7-point self-monitoring of blood glucose were measured. Patients were provided with a stress reducing biofeedback mobile app and instructed to use it 3 times a day. The mobile app—Serenita—is an interactive relaxation app based on acquiring a photoplethysmography signal from the mobile phone’s camera lens, where the user places his finger. The app collects information regarding the user’s blood flow, heart rate, and heart rate variability and provides real-time feedback and individualized breathing instructions in order to modulate the stress level. All clinical and biochemical measures were repeated at 8 and 16 weeks of the study. The primary outcome was changes in measures at 8 weeks.

Results

Seven patients completed 8 weeks of the study and 4 completed 16 weeks. At week 8, weight dropped by an average of 4.0 Kg (SD 4.3), systolic BP by 8.6 mmHg (SD 18.6), HbA1c by 1.3% (SD 1.6), FPG by 4.3 mmol/l (4.2), and serum TG were unchanged.

Conclusions

Stress reduction using a mobile app based on biofeedback may improve glycemic control, weight, and BP.