Heart Rate Variability and Emotion Regulation

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:

1. 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.
2. 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.


Eligibility Criteria:
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