Breath and mind: hrv, amygdala, and how to improve your mental state

Your breath and mental state can feel intertwined at times. A slow deep breath can leave you calm, while a rapid shallow breath can leave you anxious. Intuitively, this makes sense.

But is there a genuine connection between how you breathe and your mental and emotional state?

The answer seems to be a resounding yes. The way you breathe, particularly slow breathing, directly impacts several physiological parameters associated with your mental state: heart rate variability, brainwave activity, and brain connections.

Let's explore what scientific research tells us about the breath-mind connection in relation to our emotions and mental state.

Breathing and Emotions: A Two-Way Street

Twenty years ago, two interesting research experiments happened that helped highlight the role of breathing and emotions.

Scientists first asked participants to generate emotions such as joy and anger. Then, they had participants rate how their breathing felt afterward. It was discovered that different emotional states led to different breathing patterns. For example, they reported that a feeling of joy resulted in slower breathing with higher amplitude. Anger and fear resulted in faster breathing.

The second study they carried out was even more telling. Using the prior results, they had a separate set of participants breathe in the patterns described above without telling them why. It turned out that the emotions could be reverse-engineered. For example, the “joy breathing” resulted in more positive feelings and the “anger breathing pattern” elicited feelings of anger, along with feelings of anxiety and fear. Other breathing patterns were less conclusive but generally resulted in the emotion they targeted. For instance, the fear breathing pattern caused fear, but it also caused anxiety at a similar intensity.

Emma Seppälä, Ph.D., summarizes these findings perfectly in her book The Happiness Track: “The finding that we can change how we feel by using our breath is revolutionary.”

To better understand this revolutionary finding, let’s focus on how the physiological effects of slow breathing (breathing less than 10 breaths/min) are associated with better emotional and mental health.

 

Slow Breathing and Positive Mental Outcomes: HRV, RSA, and Brainwave Activity

In 2018, a group of researchers surveyed the published scientific literature to answer the following question: What physiological changes are common among slow breathing studies that show improvements in mental state (like less stress & anxiety)?

There were mixed results and contradictory findings. But, from the 15 papers they analyzed, three shared themes did emerge. Participants with positive psychological outcomes also had higher respiratory sinus arrhythmia (RSA), higher heart rate variability (HRV), and higher alpha brainwave activity with reduced theta brainwave activity. Together, these results indicate that slow breathing and better mental states are associated with activating the parasympathetic (rest-and-digest) nervous system.

Critically, the authors provided data that nasal breathing directly correlates with brain activity. For instance, certain areas of the brain show oscillations synchronized with breathing, but only if the nose is used. Based on the evidence they reviewed, they hypothesize that the nose is the link between slow breathing, brain, autonomic functioning, and positive emotional outcomes.

 

Slow Breathing, HRV, and the Amygdala

Brain imaging studies also support the finding that the way we breathe affects our mental state. For example, a 2016 study showed that higher HRV (which occurs with slow breathing) is correlated with a stronger connection between the prefrontal cortex and the amygdala. The amygdala is biased toward negative information—the more it’s activated, the more stress and worry we’ll have. These imaging results indicate that higher HRV gives us better control over the amygdala. As Inna Khazan, Ph.D., succinctly puts it, “high HRV is associated with better ability of the prefrontal cortex to regulate activation of the fight-or-flight amygdala response.” This helps explain why slow breathing and its resulting increases in HRV are associated with positive mental outcomes.

 

Breathe Slowly (and through the nose) to Improve Your Mental State

Altogether, these results support our intuitive understanding of how our breath affects our minds and emotions. When we breathe slowly, we enhance RSA and HRV and alter brainwave activity. These physiological changes are associated with positive mental outcomes and brain connections related to our emotional regulation. Critically, the nose might be the fundamental link between all these outcomes.

 

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These are expert opinions on lifestyle from professionals who are board-certified physicians, registered dietitians, or healthcare professionals. This content does not represent any medical advice for the prevention or treatment of any medical diseases.