Managing Post-Traumatic Heart Rate Variability and Stress with Biofeedback

Brain with Colorful Lights in Background

Traumatic brain injury has many physiological consequences. In addition to the acute symptoms that define a traumatic brain injury such as loss of consciousness, alteration of consciousness, and amnesia, people who have suffered from single or multiple exposures to head injury complain of long-term symptoms. Physical pain such as headaches, cognitive deficits such as poor concentration, psychological difficulties such as increased irritability and/or depression, and visual and hearing disturbances are common chronic consequences of TBI.

Disruptions to the Autonomic Nervous System

Recent evidence suggests the autonomic nervous system is disrupted as a result of TBI, and this disruption may be partially responsible for some of the psychosocial manifestations of TBI. The autonomic nervous system is comprised of the sympathetic and parasympathetic divisions, which are often described as being responsible for the “fight or flight” and the “rest and digest” responses, respectively. This means the sympathetic nervous system is excitatory, and promotes physiological functions that maintain attention and vigilance during times of stress, while the parasympathetic nervous system is inhibitory and slows physiological functions in a normal (non-threatening) environment.

Heart Rate Variability & TBI

Heart rate variability (HRV) measures the time between heart beats (the inter-beat interval; IBI) and gives information about the balance between the subdivisions of the autonomic nervous system. Though our heart beats feel as though they occur at regular intervals, a healthy heart shows time differences on the order of milliseconds between heart beats. High HRV indicates a healthy balance between the sympathetic nervous system, which maintains a fast, regular heart rate and is useful during times of stress, and the parasympathetic nervous system, which disrupts the fast peacemaker activity of the SNS to slow our heart rate when there is no present danger.

Conversely, low HRV is indicative of low parasympathetic tone and often correlates with a state of hyper-vigilance, even under conditions that are not consciously perceived as threatening. Interestingly, it has been reported in literature over the past several years that individuals who have suffered from traumatic brain injury exhibit lower HRV than those who have not experienced TBI. This suggest parasympathetic dysfunction as a result of TBI.


One way to combat the constant high parasympathetic activity and a constant state of vigilance is through the use of biofeedback. Biofeedback is a mind-body training technique that teaches patients to synchronize their breathing with certain physiological functions in an effort to promote relaxation. Biofeedback has proven to be an effective therapy to treat and manage a wide variety of clinical conditions, ranging from motion sickness to post-traumatic stress disorder.

Biofeedback is particularly useful in managing stress and anxiety. As a tool to manage stress and anxiety, one branch of biofeedback trains its participants to synchronize their breathing with their heart beat. A caveat to this therapy is that once the participant has reached the point that their heart and breathing rates have increased sufficiently to be noticeable, the state of high stress may impede the ability of the participant to effectively use the technique to promote relaxation. In contrast, changes in HRV are significantly more subtle, and begin to occur before the tell-tale signs of significantly heightened heart rate and breathing pace. As mentioned previously, in a healthy heart, the variability between heart beats is on the order of milliseconds; this is not a difference that is perceptible without proper measurement.

Possible Solution from Lief Therapeutics

A solution to this challenge may be found in a new device from Lief Therapeutics. Lief Therapeutics has established a kick-starter campaign to develop a wearable patch that tracks the user’s heart beat and breathing patterns, and helps the user manage stress through biofeedback training exercises. The device alerts the wearer to subtle signs of stress, including:

  • Minor changes in breathing
  • Heart rate
  • Heart rate variability

Upon detection of such changes, the device emits a gentle vibration that serves as a reminder to the user to be mindful of their mental state.

A smartphone-linked app helps the user engage in exercises designed to reduce stress in early stages. Though the product is still in development, it has great potential as a non-invasive, risk-free strategy to help manage stress in daily life. For more information on the progress of the Lief Therapeutics HRV monitoring patch, visit

If you currently suffer from a brain injury that could have been prevented, contact a personal injury lawyer at Scarlett Law Group for help.

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