Anxiety May Not Be Just in Your Head. It Can Start in Your Heart

Written by Yuhong Dong, M.D., Ph.D and Chris Chen on May 9, 2023. Posted in Current News

Research takes a closer look at the heart-brain axis and how the heart’s signals to the brain may decide how we feel

Our body is truly amazing, with two vital organs—the heart and the brain—working together seamlessly to keep us alive and healthy.

The heart acts as a pump, tirelessly circulating blood through the vascular system, providing oxygen and nutrients to the brain, lungs, and other organs to function properly.

Meanwhile, the brain serves as the command center, communicating with the body through the nervous system.

The communication between the heart and brain is a dynamic, ongoing, two-way dialogue, with each organ continuously influencing the other’s function.

Recent scientific research has revealed the complex interactions between these two organs, highlighting that the heart can also play a role in our behavior and physiology.

One significant finding is that variations in heart rhythm may contribute to developing or exacerbating anxiety, one of the most common mental health conditions.

Increased Heart Rate Can Trigger Anxiety

A recent study by a group of neuroscientists from Stanford University investigated the relationship between increased heart rate and anxiety behaviors in a particular set of genetically modified mice.

The researchers used light to activate specific cells in the heart of these mice to test the hypothesis that an increase in heart rate can trigger anxiety.

Led by Dr. Karl Deisseroth, a professor of bioengineering and psychiatry and behavioral sciences at Stanford, the researchers employed a novel, non-invasive optical pacemaker to control electrical activity in the hearts of the mice.

When the pacemaker detects light, it activates signaling pathways in light-sensitive cells, eventually transmitting information to the brain that light has been detected.

The study revealed that light stimulation from the optical pacemaker activated specific proteins in the hearts of mice, leading to increased electrical signaling in the heart cells and a subsequent increase in heart rate. The mice became more anxious as their hearts beat faster, and they showed less willingness to explore open areas or look for water.

This is clear evidence, at least in mice, that increasing the heart rate can cause anxiety, suggesting that, alongside the brain, the heart may play a role in the development of emotional states.

How Does Heart Rate Variability Influence Anxiety?

The study revealed that activity in the insula—a region of the brain involved in processing emotions and bodily sensations—increased when the heart rate increased.

The researchers also found that inhibiting the insula during optical pacing reduced anxiety behaviors in mice. These results suggest that the insula plays a crucial role in transmitting information about heart rate to the brain, thereby influencing anxiety levels.

Overall, this groundbreaking study provides important insights into how specific brain structures, such as the insula, mediate anxiety-related behaviors in response to heart rate changes.

To put it another way, understanding the origin of mood or emotional states requires considering the mutual involvement of the brain and the heart.

Studies have shown that the heart communicates with the brain in four main ways: through nerve impulses, hormones, pressure waves, and electromagnetic field interactions. This communication is significant and can affect brain activity and may induce anxiety.

In clinical practice, people with cardiovascular disease often experience anxiety and related disorders, which can have a negative impact on their heart health. Anxiety has been associated with an increased risk of adverse cardiovascular outcomes and may contribute to developing and worsening heart disease.

The relationship between anxiety disorders and cardiovascular disease can be attributed to multiple factors, including autonomic dysfunction, inflammation, endothelial dysfunction, and changes in platelet aggregation.

Heart-to-Brain Communication

The brain serves as the central control system for the entire body, with numerous pathways for signals to travel from the brain to other parts of the body, including the heart.

Simply put, the body constantly sends messages to the brain, much like a series of text messages or phone calls. However, instead of using a phone or computer, the body uses a complex network of nerves and feedback loops to communicate with the brain.

These nerves act as tiny messengers, collecting information about our internal and external environment, including what we see, smell, touch, and taste. Once this information reaches the brain, it’s processed and combined with other sensory stimuli and memories, resulting in our perception of the world.

This means that the colors we see, the scents we smell, and the flavors we taste are all products of our body’s ongoing conversation with the brain.

How Does the Heart-Brain Axis Regulate Anxiety?

The “heart-brain axis” refers to the two-way communication and interaction between the heart and the brain. If you’re unfamiliar with the term, it may sound baffling, but it’s just another way of emphasizing the interdependence of heart and brain functions.

The heart is more than just a pump; it has its own internal nervous system that can perceive and respond to its environment independently of the brain. This axis has been shown to play a crucial role in regulating a wide range of physiological and psychological processes, including mood and anxiety.

Recent scientific research has discovered that the heart sends more information to the brain than the brain sends to the heart, highlighting the intricate nature of their communication, which appears to be more complex than initially believed.

Furthermore, it has been discovered that the intrinsic cardiac nervous system can function independently of the central neuronal command. This finding adds to our understanding of the complexity of the heart’s function and its relationship to the brain.

Anxiety activates the sympathetic nervous system, which can cause an increase in heart rate, blood pressure, and respiratory rate. This activation can sometimes lead to changes in the heart’s electrical activity, potentially resulting in irregular heartbeats or arrhythmias.

The heart-brain axis is critical in regulating this anxiety response. According to research, when the heart functions properly, it sends signals to the brain that reduce anxiety and stress. This is accomplished by releasing anti-anxiety hormones, such as oxytocin and vasopressin.

Anxiety is widely acknowledged as a very complex condition, influenced by many factors that vary significantly from one person to another. The brain-heart axis is just one system involved in the body’s response to stress.

When the heart does not function properly, as in the case of heart disease, it may contribute to an imbalance in the heart-brain axis, increasing the risk of anxiety and other mental health disorders.

In short, the heart-brain axis plays a crucial role in regulating anxiety. When the heart is unhealthy, there may be an increased risk of anxiety and other mental health conditions. Conversely, a healthy heart reduces anxiety and stress.

Many organs in our body communicate with our brain through various “axes,” including the stomach-brain axis. Scientists refer to the brain’s constant perception of signals from within the body, including those from the respiratory, gastrointestinal, and cardiovascular systems, as interoception. Interoception is a vital part of our subconscious.

The subconscious is a psychological term that refers to mental processes that occur below the level of awareness. These processes can include emotions and thoughts. They are the organism’s automatic, or subconscious, response to external stimuli.

Diagnosis and Symptoms of Anxiety

Anxiety disorders are diagnosed based on specific criteria, as described in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM). It defines anxiety as excessive worry and apprehensive expectations that occur on more days than not for at least six months and involves several events or activities, such as work or school performance.

According to the DSM, to meet the diagnostic criteria for generalized anxiety disorder (GAD), a person must experience excessive anxiety and worry for at least six months, along with three or more of the following symptoms:

• restlessness or feeling keyed up or on edge
• being easily fatigued
• difficulty concentrating or mind going blank
• irritability
• muscle tension
• sleep disturbance, such as difficulty falling or staying asleep, or restless and unsatisfying sleep

Many of the above symptoms of anxiety are contributed by subconscious feelings.

How to Alleviate Anxiety

Anxiety disorders are the most common mental disorder, affecting almost 30 percent of adults at some point in their lives. Fortunately, anxiety disorders are treatable, and many effective treatments are available.

Treatment can help most people lead productive lives. The Stanford University study discovered how a racing heart could lead to anxious behavior and provided insights into current strategies for treating anxiety.

Heart Rate Variability Biofeedback

Heart rate variability (HRV) biofeedback is a popular technique that provides real-time feedback on heart rate and respiration changes while instructing people to breathe in a controlled manner. It has shown promise as an intervention tool for anxiety and depression.

In a study published in the Frontiers in Neuroscience, researchers found that using HRV-biofeedback can increase heart rate variability by 18 percent and decrease heart rate by 5.2 beats per minute. This leads to changes in a broad functional network of brain regions, including the amygdala, which controls emotions, and the insula.

Other potential mechanisms for the effectiveness of HRV-biofeedback have been proposed, including restoring the inner balance of our autonomic nervous system (the part that controls automatic functions) and reducing inflammation.

Mind-Body Practices

Mind-body practices, including yoga, tai chi, mindfulness meditation, and relaxation techniques, have been increasingly studied for their potential to alleviate anxiety symptoms.

The current body of research suggests that these practices may be effective as a treatment for anxiety, either as stand-alone interventions or in combination with conventional therapies such as medication and psychotherapy.

• Studies have shown that yoga can reduce anxiety symptoms associated with generalized anxiety disorder, panic disorder, and post-traumatic stress disorder.
• Tai chi has been found to positively affect anxiety symptoms, including reduced levels of stress hormones and improved mood.
• Mindfulness meditation can reduce symptoms of anxiety and depression and may be particularly effective for individuals with anxiety disorders.
• Relaxation techniques, such as progressive muscle relaxation and deep breathing exercises, have also been effective in reducing anxiety symptoms, including panic disorder, anxiety disorder, and social anxiety disorder.

While more research is needed to fully understand the mechanisms and efficacy of mind-body practices for anxiety treatment, the current evidence suggests that these practices may be helpful tools in managing symptoms of anxiety and improving overall well-being.

However, it is important to note that mind-body practices should not be used as a substitute for conventional treatments but rather as a complementary approach to be used in conjunction with other evidence-based treatments.

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Header image: American Psychological Association

About the author: Yuhong Dong, M.D., Ph.D., is a senior medical columnist for The Epoch Times. She is a former senior medical scientific expert and pharmacovigilance leader at Novartis Headquarters in Switzerland, and was a Novartis award winner for four years. She has preclinical research experience in virology, immunology, oncology, neurology, and ophthalmology, and also has clinical experience in infectious disease and internal medicine. She earned her M.D. and a doctorate in infectious diseases at Beijing University in China. 

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