Heart Rate Variability and Emotion Regulation

Study Overview
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Brief Summary
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Previous research suggests that heart rate variability (HRV) biofeedback aimed at increasing HRV can reduce anxiety and stress. However, some mental quiescence practices that reduce HRV during the practice sessions also lead to positive emotional outcomes. Thus, it is not obvious that the benefits of HRV-biofeedback accrue due to increasing HRV during the session. An alternative possibility is that the benefits arise from engaging prefrontal control over heart rate. In this study, the investigators will test two possible mechanisms of the effects of HRV on emotional health by comparing two groups. In one group, participants will be asked to engage in daily training to decrease HRV using the HRV biofeedback device. In the other group, participants will be asked to engage in daily training to increase HRV using the HRV biofeedback device. This will allow analyses to pit two possible mechanisms against each other: Mechanism 1: engaging prefrontal control over heart rate is the critical factor that allows HRV biofeedback to help improve well-being. In this case, well-being should increase over time in both groups, as both training should engage prefrontal cortex to implement self-directed control over heart rate. Strengthening prefrontal control mechanisms may help improve emotion regulation in everyday life. Mechanism 2: increased HRV during the training sessions leads to greater functional connectivity among brain regions associated with emotion regulation during the high HRV state. In this case, improved well-being would be specifically associated with having time each day during which there were very high HRV states, and so improved well-being should be seen only in the group in which participants get biofeedback to increase HRV.

Official Title
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Why Does Heart Rate Variability Matter for Emotion Regulation

Conditions
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Heart Rate Variability

Intervention / Treatment
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* Behavioral: HRV training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fluent in English Aged between 18-35 for the younger group and aged between 55-80 for the older group Scores on TELE indicate no current dementia Normal or corrected-to-normal vision and hearing People taking antidepressant, anti-anxiety medication and/or attending psychotherapy only if the treatment had been ongoing and unchanged for at least three months Exclusion Criteria: Have a disorder that would impede performing the HRV biofeedback procedures (i.e., abnormal cardiac rhythm, heart disease including coronary artery disease, angina, and arrhythmia, cardiac pacemaker, stroke, panic attack, cognitive impairment). Current practice of any relaxation, biofeedback, or breathing technique. Currently taking any psychoactive drugs other than antidepressants or anti-anxiety medications No trips that would lead them to miss any of the weekly meetings Currently nursing, pregnant, or intend to become pregnant Have metals in their body, as this is a scanning requirement Have any conditions listed in the MRI Screening form (see below) MRI screening Cardiac pacemaker Implanted cardiac defibrillator Aneurysm clip or brain clip Carotid artery vascular clamp Neurostimulator Insulin or infusion pump Spinal fusion stimulator Cochlear, otologic, ear tubes or ear implant Prosthesis (eye/orbital, penile, etc.) Implant held in place by a magnet Heart valve prosthesis Artificial limb or joint Other implants in body or head Electrodes (on body, head or brain) Intravascular stents, filters, or Shunt (spinal or intraventricular) Vascular access port or catheters IUD or diaphragm Transdermal delivery system or other types of foil patches (e.g. Nitro, Nicotine, Birth control, etc.) Shrapnel, buckshot, or bullets Tattooed eyeliner or eyebrows Body piercing(s) Metal fragments (eye, head, ear, skin) Internal pacing wires Aortic clips Metal or wire mesh implants Wire sutures or surgical staples Harrington rods (spine) Bone/joint pin, screw, nail, wire, plate Wig, toupee, or hair implants Asthma or breathing disorders Seizures or motion disorders Hospitalization for mental or neurological illness Head Trauma Migraine Headache Panic attack Stroke

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants will be randomly assigned to either the HRV-increase group or the HRV-decrease group.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HRV-increase group<br>Half of the participants will be randomly assigned to this group who will undergo daily practice to increase their heart rate variability (HRV). | Behavioral: HRV training<br>* Participants will be asked to undergo daily practice to regulate (either increase or decrease) HRV for 5 weeks.<br>|
| Experimental: HRV-decrease group<br>Half of the participants will be randomly assigned to this group who will undergo daily practice to decrease their HRV and heart rate. | Behavioral: HRV training<br>* Participants will be asked to undergo daily practice to regulate (either increase or decrease) HRV for 5 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MPFC-amygdala functional connectivity | The investigators will compute right amygdala - mPFC functional connectivity values during resting state and fMRI scan for the Time 1 (before HRV biofeedback) and Time 2 (after HRV biofeedback) scans. The investigators will then compute the difference in these functional connectivity values before and after biofeedback (Time 2 - Time 1) for each group. | two time points: an average of 5 weeks between Time 1 and Time 2 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Emotion regulation (behavior) | The investigators will examine the difference between Time 1 and Time 2 and between groups in emotion regulation ability measured by self-reported effectiveness when instructed to regulate emotion during viewing emotional pictures. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Emotion regulation (fMRI) | The investigators will examine the difference between Time 1 and Time 2 and between groups in the ability to up- and down-regulate amygdala activity when instructed to regulate emotion during viewing emotional pictures. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Decision-making (behavior) | The investigators will examine the difference between groups in decision-making ability measured by multiple-choice responses during a computer-based task. | one time point: at study completion, which is the end of 5-week training | 
| Decision-making (fMRI) | The investigators will examine the difference between groups in the ability to up- and down-regulate task-relevant brain regions during a computer-based task. | one time point: at study completion, which is the end of 5-week training | 
| Emotional well-being | The investigators will examine the difference between Time 1 and Time 2 and between groups in emotional well-being by using standardized questionnaires. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Stress recovery | The investigators will examine the difference between Time 1 and Time 2 and between groups in recovery from stress elicited by standard cognitive tasks. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Stress reactivity | The investigators will examine the difference between Time 1 and Time 2 and between groups in stress reactivity elicited by standard cognitive tasks. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| HRV | The investigators will examine the difference between Time 1 and Time 2 and between groups in HRV measured by high frequency (HF) HRV. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| HRV | The investigators will examine the difference between Time 1 and Time 2 and between groups in HRV measured by low frequency (LF) HRV. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| HRV | The investigators will examine the difference between Time 1 and Time 2 and between groups in HRV measured by the root mean square of successive differences (RMSSD). | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Inflammatory markers | The investigators will examine the difference between Time 1 and Time 2 and between groups in inflammatory markers including C-reactive protein and cytokines. | two time points: an average of 5 weeks between Time 1 and Time 2 | 
| Arterial Spin Labeling (ASL) | The investigators will examine the difference between groups in cerebral blood flow during rest and paced-breathing using ASL technique. | one time point: at study completion, which is the end of 5-week training | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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heart rate variability, HRV