How the Parasympathetic Nervous System Influences Your Mental Health

Stress seriously affects your body, mind, and ability to feel like yourself. While you might feel like you’re stuck in a constant state of tension, it’s easy to forget that your body is also designed to recover. Your body’s parasympathetic nervous system (PSNS) helps you return to a relaxed state after dealing with stress. It allows you to feel grounded, calm, and at ease.

According to Bonnie Mitchell, DBH, LPCC, the clinical director at Healthy Life Recovery, the parasympathetic nervous system is a crucial, yet often overlooked aspect of mental health. “This ‘rest and digest’ system acts as a vital counterweight to our body’s stress response, and understanding its influence can be profoundly beneficial in working towards mental well-being,” says.

While it is often overshadowed by its high-alert counterpart, the sympathetic nervous system, the PSNS has a powerful role in managing how your body handles stress. Understanding how it works—and how you can harness its ability to calm your mind and body—can be vital for your mental well-being, whether you’re coping with chronic anxiety, trying to sleep, or just trying to feel a little calmer and more connected. 

Keep reading to learn more about how the parasympathetic nervous system works, how it affects mental health, and how to know if it’s not functioning properly. We’ll also explore some expert-backed tips for supporting your PSNS through simple lifestyle changes.

Understanding the Parasympathetic Nervous System

The parasympathetic nervous system is part of the body’s autonomic nervous system (ANS). The ANS deals with essential body functions automatically—all of the processes that happen without you even having to think about them, like breathing, heart rate, and blood pressure. 

“While the sympathetic system helps you deal with things and get stuff done, the parasympathetic system helps you rest, heal, digest, and recover,” explains psychiatrist Alex Dimitriu, MD.

It’s the sympathetic system that kicks into gear when you are faced with some type of stressor or threat and prepares you to either fight, flee, or freeze. When activated, this system elevates your heart rate, floods your body with stress hormones, and slows digestion so you’re ready to act fast.

The parasympathetic nervous system is all about rest and recovery. That’s why it’s often referred to as the “rest and digest” system—and that’s exactly what it does. It slows your body down so you can repair tissue, process food, and return to a calmer, more balanced state. 

Both systems are critical. There are times when you need to be ready to take action, and times when you need to rest and relax. 

“Short-lived stress is healthy and normal and pushes us to action,” Dr. Dimitriu says. Problems start to happen, however, when your body gets stuck in that high-alert state. “Chronic stress can lead to excess sympathetic drive and a variety of health issues, to some degree because the body is less in a parasympathetic state and never has a chance to recover and heal,” he continues.

When you have trouble shifting back into recovery mode, you begin to feel the effects of chronic stress. For example, research suggests that prolonged activation of the sympathetic nervous system caused by chronic stress leads to elevated stress hormones like epinephrine and cortisol. This contributes to oxidative stress and inflammation, leading to cardiovascular as well as other medical problems.

Functions of the Parasympathetic Nervous System

When your parasympathetic nervous system becomes active, it triggers your body to relax and focus on restoration. This change affects nearly every major system in your body, which is why it is so important for your long-term health and well-being.

Key functions of the parasympathetic nervous system include:

• Slowing heart rate: The PSNS helps lower your heart rate after you’ve dealt with a stressful event. 
• Stimulating digestion: Where digestive activity was slowed during the SNS activation, the PSNS increases activity in the digestive tract so you are able to process and absorb nutrients that your body needs.
• Enhancing immune function: The PSNS also reduces inflammation throughout the body. This fosters a better immune response, so your body is better able to heal and fight off illness.
• Promoting salivary and tear function: The PSNS increases tear production and causes the glands in your mouth to produce more saliva. Increased saliva is important for digestion and helps with breathing while you are resting or asleep.
• Supporting reproductive processes: The PSNS has an important role in sexual and reproductive functioning, including arousal during sexual activity.
• Facilitating elimination: Stress can disrupt bladder and bowel function. The PSNS helps support these functions to help with waste removal. Have you ever realized that you feel the urge to use the bathroom as soon as you unwind after a stressful situation? This is why.

“In my clinical experience, prolonged stress creates a chronic imbalance in the autonomic nervous system. The sympathetic nervous system—the fight or flight side—gets stuck in overdrive, while the parasympathetic nervous system (PSNS)—which should bring the body back to a calm, regulated state—gets suppressed, says Sean Leonard, a board-certified psychiatric nurse practitioner at Healthy Life Recovery. 

“Over time, this dysregulation wears down the body and brain, impacting immune function, mood stability, and emotional resilience,” Leonard explains.

The Parasympathetic Nervous System and Mental Health

The parasympathetic nervous system isn’t just about calming different body systems—it also plays a crucial role in mental health and well-being. It affects how we handle stress, our ability to bounce back after emotional upheaval, and our ability to regulate mood over time. So when this system gets thrown off, it can have resounding effects on everything from anxiety levels to sleep to gut health.

The Stress Response

Think about a high-stress situation you’ve dealt with, like running late for an important meeting or getting some unexpected bad news. During these moments, the sympathetic nervous system takes control. It fires up the fight or flight response so you can deal with it.

This response is helpful when it happens in short bursts, but problematic if you get stuck in that stressed-out mode and your body doesn’t get the message that it’s time to calm down.

“While our sympathetic nervous system (SNS)—the ‘fight or flight’ response—is essential for navigating immediate threats, chronic activation takes a significant toll,” Dr. Mitchell explains. “Think of it like constantly revving your car engine; eventually, the system will become strained and less efficient.”  

Dr. Mitchell continues, “Prolonged stress tends to downregulate the body’s response to the PSNS. This means the body becomes less adept at shifting out of the stress response and back into a state of calm,”

Dr. Dimitriu also says that when the PSNS becomes dysregulated, it can lead to lower heart rate variability (HRV). HRV is a key indicator of how well your body responds to stress. Research has shown that lower HRV is linked to higher levels of anxiety, depression, and burnout.

“Individuals may find it harder to relax, their heart rate might remain elevated, and digestive issues can become chronic. This impaired PSNS function creates a fertile ground for mental health challenges to take root and flourish,” Dr. Mitchell says.

How the PSNS Affects Anxiety and Panic

An overactive sympathetic nervous system and an underactive parasympathetic nervous system can be a factor in the development of anxiety and even panic attacks. When your body gets stuck in the hyper-alert state, it may means that even small, everyday stressors can seem almost overwhelming.

“In anxiety disorders, the PSNS often isn’t kicking in effectively, meaning the body doesn’t recover well from stress. Instead of returning to baseline after a trigger, the nervous system stays activated, feeding the anxiety loop,” Leonard explains.

That’s why practices that stimulate the parasympathetic system, like deep breathing and progressive muscle relaxation, are frequently used in anxiety treatments. These techniques help to re-regulate the nervous system, which can reduce the intensity and frequency of anxiety symptoms.

Leonard notes that a combined approach that includes medications like SSRIS and SNRIs, along with psychotherapy approaches that optimize lifestyle strategies, is often the most effective treatment for anxiety symptoms.

PSNS Dysregulation Can Contribute to PTSD and Depression

Trauma-related conditions like post-traumatic stress disorder (PTSD) are often characterized by autonomic nervous system dysregulation. Essentially, the sympathetic system becomes overactive while the parasympathetic system becomes underactive. 

When this happens, people may experience symptoms such as insomnia, emotional numbness, hypervigilance, and difficulty feeling safe. Such symptoms occur even when there is no immediate threat. Reduced parasympathetic activity can also be seen in depression, where it can contribute to problems like fatigue and digestive issues.

Leonard says that treatments like trauma-informed care and somatic therapy can help. These approaches can help restore balance between the sympathetic and parasympathetic systems.

The Brain-Gut Connection

The connection between the brain and gut has received more attention in recent years. The vagus nerve, an important messenger between the two, is an integral part of the parasympathetic nervous system. Research has also shown that digestive issues often occur in conditions like anxiety and depression, indicating another connection between the brain and gut.

When the PSNS functions well, it helps support gut motility, healthy digestion, and nutrient absorption. Disruptions and impairments caused by chronic stress or trauma can break down the communication between the brain and gut, which is why people often experience problems with bloating, stomach upset, and even changes in mood and cognition.

Signs of Parasympathetic Nervous System Dysfunction

When your PSNS isn’t doing its job as well as it should, your body might start to send some signals that something’s not quite right. Such signals are often subtle at first. You might notice changes in your sleep, digestion, and how quickly you bounce back from stress. 

“The body is prepping for battle. When this happens occasionally, this is okay; but when this occurs continuously over time is a health disaster,” Dr. Dimitriu says. This includes problems with elevated heart rate, increased blood pressure, poor sleep, and, for some, elevated glucose levels.

Over time, this can lead to more serious mental and physical health challenges. A few signs you might be experiencing PSNS dysfunction include:

Persistent Digestive Problems

You might struggle with constipation or diarrhea as well as bloating. Because the parasympathetic system plays such a key role in digestion, your gut can feel seriously out of sync. Such symptoms may mimic or overlap with conditions like irritable bowel syndrome (IBS).

Trouble Relaxing

Even when the stress is over, you may find it difficult or impossible to relax. That’s a sign that your parasympathetic nervous system isn’t counterbalancing the effects of the sympathetic system like it should.

Sleep Problems

Difficulty falling asleep, staying asleep, or waking up tired can be connected to PSNS dysregulation. In order to get the deep, restorative rest you need, your nervous system needs to be calm and grounded.

Lack of Energy

When you don’t get enough time in rest and digest mode, your body never gets a chance to recharge. This can lead to low energy, fatigue, and brain fog.

Elevated Heart Rate

A higher-than-normal resting heart rate and low heart rate variability can indicate problems with the parasympathetic nervous system. When HRV is low, it can mean you are experiencing more stress and reduced resilience.

Emotional Reactivity

Lack of balance between parasympathetic and sympathetic activity can also contribute to greater sensitivity to stress and problems managing emotions. Even minor irritations and stress can trigger intense emotions that are out of proportion to the situation and hard to manage.

“Emotionally, people may become impatient, reactive, intense, moody, and lack a sense of sustainable joy,” Dr. Dimitriu says.

Frequent Illness

If you feel like you catch every bug that’s going around, it might be due to poor PSNS activity. The parasympathetic system is important for regulating inflammation and immunity, so PSNS dysfunction can manifest as frequent colds, illness, infections, and slow healing.

While such indicators might point to a problem with your parasympathetic system, it’s important to remember that there might be other causes as well. But if you start to notice a pattern, it might be time to consider how your PSNS is functioning and what you can do about it.

Maintaining a Healthy Parasympathetic Nervous System

Even if your PSNS is out of whack, there is good news. You can make lifestyle changes to help train your parasympathetic nervous system to work more effectively. The key? Consistent habits that help shift your body from keyed up to calm. That way, you can shift into that calm, restorative state more readily.

Dr. Dimitriu suggests slowing things down. In addition to tracking down the sources of stress that are creating agitation, he recommends setting boundaries and learning how to say no more often. “Allow time for transitions, time to stare, time to think, and time to relax,” he says.

Some lifestyle changes and relaxation practices that can help activate and strengthen your parasympathetic nervous system include:

Slow, Deep Breathing

Breathing is one of the most important ways to influence your nervous system and achieve a more relaxed state. Techniques such as box breathing (inhale for 4 counts, hold for 4, exhale for 4, and hold for 4) or the 4-7-8 technique (inhale for 4, hold for 7, exhale for 8) can stimulate the vagus nerve and promote better parasympathetic activity.

“Dedicate even a few minutes each day to slow, deep breaths. Inhale deeply through your nose, allowing your abdomen to rise, and exhale slowly through your mouth. This simple act directly stimulates the vagus nerve,” Dr. Mitchell explains.

Practice Mindfulness

Mindfulness practices can also be a powerful way to boost parasympathetic activity. Techniques like body scan meditation and yoga can help improve vagal tone and reduce the dominance of sympathetic activity.

“Practices that bring your awareness to the present moment can help interrupt the cycle of anxious thoughts and activate the PSNS. Even short guided meditations can make a difference,” says Dr. Mitchell.

Spend Time in Nature

Research has shown that spending time outdoors in green spaces can improve parasympathetic responses. It may lower blood pressure and cortisol levels. Consider spending some time outdoors each day, whether you’re eating your lunch at a nearby park or going for a stroll in the afternoon.

Cold Exposure

Research has shown that brief exposure to cold temperatures (like splashing cold water on your face or taking a quick cold shower) can help activate the vagus nerve. Yes, really. It might sound a bit intense, but even just 30 seconds can help shift your body into a more relaxed state.

Support Your Gut Health

Prioritizing your gut health may also be helpful, since digestion and the parasympathetic system are so connected. Make sure you are eating a balanced diet and incorporate fiber, fermented foods, and probiotics. 

Dr. Mitchell says nourishing your body is important for maintaining a healthy balance. “Pay attention to how different foods make you feel. A balanced diet rich in whole foods supports overall nervous system health,” she says.

Build Safe Social Connections

Feeling emotionally safe and supported can also be a big part of regulating your nervous system. We are wired for connection, so it’s essential to build relationships that allow us to feel secure and be our authentic selves.

Such strategies aren’t a quick fix. It takes time to slowly shift your body into a place where you feel grounded, safe, and able to relax. By building good habits and taking small steps, you can foster a healthier balance between your sympathetic and parasympathetic systems. 

“The parasympathetic nervous system is not merely a passive “off switch” for stress; it is an active and vital component of our mental well-being,” says Mitchell.