Stress, HRV, and Gut Health - Hanu HRV
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Stress, HRV, and Gut Health

If you’re a regular reader of our blog, you’ve learned a lot about the importance of heart health and heart rate variability for helping you stay connected with your body’s natural healing mechanisms. 

While the heart is the energetic center of your body that helps feed tissues and organs with blood and oxygen, it’s essential to understand that the heart isn’t an isolated organ unaffected by the health of other parts of the body. The same goes for your heart rate variability – as these scores can be affected by all systems of the body. 

Your gut health, for instance, plays a significant role in your heart health. It also affects your HRV wearable readings.

You can’t take care of your heart or health without taking care of your gut health. 

There’s a deep connection between your heart, HRV, brain, and gut health, all of which work synchronously to keep your body maintained and healthy. 

The Importance of Gut Health

The Role of Gut Health 

Your gut can be thought of as your “second brain.” The gut helps produce critical chemicals such as serotonin, which influence your mood and memory. When working correctly, our gut digests our food and absorbs nutrients so we can have energy and vitality; it eliminates toxins, fights pathogens, and helps coordinate essential actions with the brain.

It’s also the home of trillions of microorganisms that aid in these processes, including managing inflammation and producing neurotransmitters. Crazy enough, your gut bacteria are responsible for creating 95% of your body’s serotonin. Many healthcare providers and leading holistic treatment professionals recommend treating gut health first and foremost

Your stomach health and microbiome have an intricate connection with the vagus nerve. The vagus nerve is the longest in the body and travels from the brain down the spinal cord. 

The autonomic nervous system and the sympathetic and parasympathetic divisions are key stress modulators. However, a third branch of the autonomic nervous system, the enteric nervous system, is responsible for nervous system regulation.  

The nerves that make up this regulatory system connect to all the most significant organs and are in charge of the parasympathetic system’s effects. This division of your nervous system is responsible for calming the body down after a stressor, better known as the “rest and digest” response. 

The PNS helps bring our heart rate down and puts the body in a relaxed, restful state that is optimal for digestion and overall maintenance. The vagus nerve is associated with increased “happy hormones” like serotonin, acetylcholine, and dopamine. 

It can inhibit the release of chemical messengers in the body called inflammatory cytokines, which are associated with an increase in many mental and physical issues, including depression.

How The Gut and the Heart Are Connected 

The heart and the gut are both connected by the vagus nerve. 

70% of the fibers in the vagus nerve point upstream towards the brain. The flow of information works by triggers first experienced downstream in the gut. 

So, the signals wired to the brain by the heart and gut significantly impact the brain. The gut is also a powerful control center in the body because it:

  • Digests food
  • Interprets this food as information
  • Sends this information to the brain to coordinate gene function and expression

This connection is known as the gut-brain axis. When you eat healthily and keep your gut microbiome in check, your body can maintain itself properly, minimize inflammation, and keep you energetic and balanced. 

Experts have also found a deep connection between the heart and the gut. In an extensive study that tested the effects of meditation and gratitude on the heart and overall health, researchers found that the heart and gut are intricately connected to the vagus nerve.  

The Role of Heart Rate Variability 

Heart rate variability (HRV), or heart coherence, is an essential metric for assessing the state of your autonomic nervous system and vagus nerve. Essentially, HRV measures the variation in the time interval between heartbeats.

HRV is relevant here because it’s the most effective measurement for assessing your autonomic nervous system health. HRV represents the autonomic nervous system and regulates your heart rate, blood pressure, digestion, and breathing rate depending on stress and rest.

A good HRV score is more “variable” because this demonstrates that your body is shifting between action and rest healthily. When your HRV is lower for some time, this can indicate that your body is tired and needs more active rest and recovery. 

Just like the heart — your gut is also sensitive to and responds to the actions of the autonomic nervous system. In the gastrointestinal tract, activating the parasympathetic nervous system increases digestion and blood flow to the gut. 

In contrast, sympathetic activity reduces intestinal activity, reducing blood flow to the gut and allowing for a higher blood flow to the heart and the muscles. When you’re stressed, overtraining your body, or seeing a less variable HRV score, your gut likely has less energy available to coordinate with the brain and digest food properly. 

When you have a high HRV, your heart responds well to input from both branches of the ANS, so your body is more adaptable to stress and the environment. A high HRV is a measure of excellent health and fitness. Studies have shown that low HRV is associated with heart disease, depression, and anxiety.

How To Keep Your Gut Healthy

How To Keep Your Gut Healthy

Feed the Right Gut Bacteria 

We are home to some 500 different microbes, totaling around 100 trillion bacteria. Some of them help us, but others are harmful. We must starve the harmful bacteria by avoiding the foods and other forces that allow them to thrive.

Good bacteria love healthy, whole, organic, plant-based foods that are high in fiber and nutrients and contain no artificial ingredients. Ensure you eat plenty of fiber-rich foods such as apples, artichokes, avocados, bananas, celery, garlic, kale, seeds, olive oil, and cruciferous vegetables. 

Also, be sure to fit in gut-balancing, fermented foods that make your gut bacteria happy such as kimchi, pickled vegetables, and even probiotic supplements and drinks such as kombucha and low-sugar yogurts. 


We talk about meditation a lot here, but in this case, it does make a significant difference in your gut health. 

Meditation is one of the most potent tools for triggering the PNS and getting in touch with our heart health. Studies have shown that meditation practices can positively affect heart rate variability (HRV) by increasing vagal activity. 

This improved parasympathetic activation that occurs during meditation can help to improve digestive capabilities by diverting more blood to the gut and allowing it to perform maintenance. This increased blood flow leads to less inflammation and can improve metabolic efficiency, energy, mental health, learning, and cognition.

Perhaps most importantly, meditation can help you gain control over your mind and, as a result, your body. Biofeedback mechanisms occur when using breathwork to center your mind. Developing your breathwork and meditation technique keeps your body in a relaxed state. 

You begin to notice when the stress response lingers and when your body may need a break or calm down. This awareness has a far-reaching result on your body, enabling the parasympathetic nervous system to kick in and help your body rest and repair when it needs it. 

Get In Touch With Your Natural Rhythm 

Your circadian rhythm is the natural sleep-wake cycle that keeps the body in a daily rhythm. Your circadian rhythm gets developed by sticking to a regular, consistent schedule for eating and sleeping.

There is a strong connection between the microbiome and our circadian rhythm. For example, one study showed that when mice were kept on a consistent 12-hour cycle of light and dark, the activity of their gut bacteria fluctuated. During the nighttime hours, the bacteria worked to digest nutrients and repair DNA, whereas, during the light phase, the bacteria went into a “housekeeping” phase and worked to detox the gut.

The inner clock we all have profoundly affects the activity and health of our gut bacteria. Your microbiome depends on the state of your circadian rhythm. Follow a consistent sleep-wake schedule and honor your natural biological clock to promote the health of your gut bacteria and nervous system.

Take a Probiotic 

Research has shown that the bacteria in the gut can have a significant influence on the vagus nerve. Studies have determined that specific strains of bacteria can lead to decreased anxiety, better mood, improved muscle recovery, and improved nerve transmission. These studies show us that different strains of bacteria found in these probiotics help keep the gut happy while keeping the vagus nerve maintained and functioning correctly. 

Interestingly, these studies found that the vagus nerve is the mediator of the relationship between the gut microbiome and mental health. It acts as the fiberoptic cable that transmits signals from the gut to the brain. Probiotics help the body get rid of bad cholesterol and improve blood pressure, which leads to improved heart health and a decreased risk of cardiovascular disease. 

Try Intermittent Fasting

Intermittent fasting can work wonders to improve your gut health and minimize inflammation in your digestive tract. When your stomach and digestive tract constantly digest food, less energy is available to perform maintenance, causing damaging inflammation in the digestive tract and placing a lot of strain on the gut microbiome. 

Intermittent fasting doesn’t need to be overly strenuous – you only need to give your body a window of 13-15 hours of fasting a few times a week. Studies show that this simple activity can work wonders to improve the makeup of your gut bacteria.  

Happy Gut Happy Heart

A Healthy Gut = A Happy Heart 

As we can tell, your gut health has far-reaching effects on almost every aspect of your health, and your heart is no exception. Your gut is yet another system directly affected by the health of your autonomic nervous system – and a good HRV score tells us that your gut is reaping the benefits of that “rest and digest” activation. 

So make sure you eat consciously, keep your gut in good shape, and keep an eye on your HRV scores using your Hanu device as you take better care of your gut health!

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