Can You Enhance Parasympathetic Nervous System Activity?

Our world is full of stressful situations. Whether it's being late to work, having a sick kid, or conflict in your relationship, it's hard to avoid. Knowing how to support our bodies during these times of stress is critical to our overall health. Luckily, we have a built-in system to combat stressful situations we encounter. While the sympathetic nervous system (SNS) prepares the body's fight-or-flight response, the parasympathetic nervous system (PSNS) promotes relaxation.

In this article, we will focus on the parasympathetic nervous system — the body's recovery response. We'll talk about what it is, how it works, and strategies to activate it in stressful situations.

What is the parasympathetic nervous system?

The parasympathetic nervous system (PSNS) is part of the nervous system that regulates body functions when we're at rest. It's a component of the autonomic nervous system, which is responsible for all involuntary bodily functions and movements.

Commonly called the 'rest and digest' response, the parasympathetic nervous system supports how the brain recovers and relaxes after experiencing stress and threatening situations. The brain sends signals to the rest of the body to open blood vessels, promote blood flow, increase digestive system function, lower blood pressure, and reduce heart and breathing rates. This supports the body's response to stress and promotes recovery after a stressful event.

The sympathetic nervous system (SNS), on the other hand, does the opposite. It gets triggered when we experience a stressful situation, putting the body on high alert. Known as our 'fight, freeze, and flight' response, the SNS prepares the body by increasing the heart and breathing rate and contributes to the release of cortisol, one of the primary stress hormones. While the PSNS has a relaxation response, the sympathetic system has an activating one.

How to activate the parasympathetic nervous system?

Knowing how to activate the parasympathetic response is critical to manage stress and overall well-being. There are several ways to tap into the body's PSNS response and promote nervous system regulation.

Deep breathing

Breathing techniques are effective for promoting relaxation and decreasing anxiety. Slow, deep breathing, in particular, can activate the parasympathetic nervous system by stimulating the vagus nerve. Research on different breathing practices showed that deep breathing at a pace of six breaths per minute, with equal-length inhales and exhales (1:1 ratio). Findings suggest that slow, deep breathing could be a valuable clinical tool for improving vagal tone and activating the PSNS system.

Using vagus nerve devices

There are devices designed to specifically stimulate the vagus nerve and activate the parasympathetic nervous system. Known as vagus nerve stimulation (VNS) devices, they range from invasive options requiring surgery to non-invasive tools that are placed on your skin.

Invasive VNS devices are surgically implanted in the chest, where a wire is wrapped around the vagus nerve up the left side of the neck. It sends electrical impulses to the brain via vagal impulses to influence brain activity. Invasive devices are only used in drug-resistant cases of epilepsy and depression. On the other hand, non-invasive VNS devices use electrodes placed on your skin that send mild electrical impulses to the vagus nerve. They are typically placed at the base of the neck or by the outer ear.

Meditation and mindfulness

It's been long understood that meditation and mindfulness are powerful tools for managing stress and promoting mental well-being. In fact, people who meditated for at least 45 minutes every morning for three or more years showed significantly more parasympathetic function than those who had never meditated before. Resting heart rates and blood pressure were significantly lower in meditators, indicating parasympathetic dominance leading to lower stress.

Yoga and stretching

Like meditation, yoga has long been used as a way to reduce stress and improve well-being. There are several ways to practice yoga, from yin yoga, where you hold poses for an extended time, to vinyasa, where poses are linked to breathing in a flow pattern.

Yoga stretching is a low-intensity exercise form that focuses on helping the body feel relaxed. It has been shown to significantly lower cortisol and increase heart-rate variability (HRV), which measures parasympathetic nerve activity. These effects lasted up to 120 minutes after the session, suggesting this practice may have longer-lasting benefits to the PSNS.

Cold exposure

Cold plunges and cold water exposure have recently gained popularity due to their potential health benefits in supporting immune system responses, increasing blood flow, reducing inflammation, and decreasing stress. Most of these benefits require further clinical trials.

While some of these effects relate to autonomic system activation, a different approach is using cold devices called thermodes directly to the body for short amounts of time to stimulate parasympathetic activity. When thermodes are placed on the cheek and neck, they activate the vagus nerve, which increases HRV and decreases pulse rate, which are key features of relaxation. This suggests that wearable cold devices could be beneficial in treatment in promoting PSNS activation.

Spending time in nature

Biophilia is the theory that humans are biologically connected to nature, which benefits our health and well-being. These appear to be true based on the physiological and psychological benefits of being outside.

Spending time in nature may promote relaxation and better mood, as well as affect parasympathetic markers like lowering heart rate, decreasing blood pressure, and reducing cortisol levels. Regularly spending time in green spaces may help promote these benefits, however, more research is needed to better understand these effects in the long term.

Listening to music or nature sounds

Music therapy, including both listening to and playing music, may affect how the autonomic nervous system functions. It's been known to help balance the sympathetic and parasympathetic nervous systems — known as autonomic tone — which helps promote overall health. In the short term, music can reduce stress and anxiety by targeting the autonomic system. There is even some evidence that suggests the long-term benefits of engaging with music in improving autonomic tone. It can pull you out of flight mode and into rest and digest mode.

Eating a balanced diet

Studies suggest that nutrition plays an important role in maintaining the health of the autonomic nervous system. Poor eating habits may promote dysfunctions like high blood pressure, irregular heartbeat, and digestive issues. Several nutrients are linked to autonomic function, including amino acids, vitamins and minerals, and antioxidants, all of which may help speed up recovery after a stress response.

Exercise

Linked to many physical and psychological health benefits, exercise may also have a positive effect on the PSNS. Exercise can significantly improve HRV in inactive adults, particularly when it comes to vagus nerve activity. Vagus nerve activity increases after physical activity, suggesting the benefits to the PSNS. It didn't matter what time of exercise was done: aerobic training, resistance training, or a combination of the two. This suggests that it doesn't matter what form or activity you do, but getting exercise can promote PSNS activity and better overall health.

While this research is promising, it's important to remember that these approaches may not work for everyone. Some, like meditation and yoga, require practice, and it can take time to feel the effects. It may also be harder to enhance the PSNS if you have chronic anxiety or stress. In those cases, it may be best to speak to a professional.

Have you tried managing your parasympathetic system with these strategies? Share your experiences in the comments section.

Why is it important to enhance PSNS activity?

We're regularly exposed to stress in our daily lives. If not managed properly, this may lead to continual activation of the sympathetic nervous system, causing increased stress levels. The PSNS is responsible for body functions connecting to recovery. It uses the neurotransmitter acetylcholine, which works on slowing down the heart rate during elevated stress, helping to relax. The PSNS and SNS work together to keep the body in balance. When the SNS increases the pulse to respond to stress, the PSNS slows it down.

Being able to activate the PSNS is key to balancing stress. By counteracting the body's stress response, it can slow down important elevated functions that get us back into a recovery and relaxed state. Implementing practices like meditation, yoga, spending time outside, and deep breathing are some ways that can help activate the PSNS and combat everyday stress. While these may take some practice, they are important for reducing the risk of developing chronic stress and promoting long-term well-being.

Do you have questions? Please ask them in our comments section below.