The Science of Breathwork: How It Impacts Your Mind and Body

Take a deep breath in. Hold it for a moment. Now exhale slowly.

Feels different, right?

We take around 20,000 breaths every single day, yet most of us rarely pay attention to how we breathe. Over the years, I’ve seen firsthand how intentional breathwork can radically shift the way people feel, think, and perform. Science now confirms what I’ve experienced personally and through my work with clients: the way we breathe directly affects our nervous system, brain function, and overall health. Whether it’s reducing stress, enhancing mental clarity, or boosting energy levels, breathwork is a powerful tool for anyone looking to feel and function better.

How Breathwork Influences the Nervous System

Our breath is one of the few functions in the body that we can control voluntarily, which gives us a direct line to the nervous system. The autonomic nervous system, responsible for automatic processes like heart rate and digestion, has two main branches:

• Sympathetic Nervous System (SNS): activates the “fight or flight” response

• Parasympathetic Nervous System (PNS): brings the body back into a state of rest and recovery

When I work with clients, one of the first things we focus on is how slow, controlled breathing can activate the vagus nerve. This helps shift the body from a stress-driven state to one of calm and restoration.

A study found that this kind of breathing can significantly enhance heart rate variability (HRV), which is a key indicator of how well the nervous system can adapt to stress.

The Role of Oxygen and CO2 Balance in the Body

Many people assume breathing is only about getting oxygen, but carbon dioxide (CO2) plays an equally important role. In fact, when we breathe too quickly or too shallowly, we blow off too much CO2. That disrupts the way oxygen is delivered to our tissues. This is due to the Bohr effect, something I talk about extensively in The Language of Breath.

When CO2 levels drop, hemoglobin holds onto oxygen instead of releasing it where it’s needed. This can lead to fatigue, dizziness, anxiety, and poor mental focus, even when oxygen levels in the blood are technically normal.

By practicing breathwork in a way that supports CO2 tolerance, we train the body to use oxygen more efficiently. This is one of the most practical and overlooked aspects of breath training. Slow nasal breathing, breath holds, and CO2 tolerance drills help bring balance back into the system, supporting everything from clearer thinking to better physical endurance.

What the Research Says

The benefits of breathwork aren’t just anecdotal. There’s solid research backing it up.

Stress Reduction 

A 2021 study showed that participants who practiced controlled breathing experienced significant drops in cortisol levels, the body’s primary stress hormone.

Another study found that breathwork helped regulate the amygdala, the part of the brain responsible for fear and anxiety.

Mental Focus and Cognitive Clarity 

Breathwork has also been shown to boost function in the prefrontal cortex, the part of the brain responsible for decision-making and attention. Some techniques are even linked to higher levels of gamma brain waves, which help with learning and memory.

Energy and Physical Performance 

In 2023, researchers published findings in Cell Reports Medicine showing that rhythmic breathwork can improve oxygen efficiency and endurance. And while I don’t follow every aspect of the Wim Hof Method, research around it shows increased adrenaline and reduced inflammation, both of which support recovery and stamina.

Breathing Techniques I Recommend for Beginners

If you're just getting started, here are three techniques I often teach in my workshops and courses.

Box Breathing 

This method helps regulate your nervous system and sharpen your focus.

• Inhale through your nose for 4 seconds

• Hold for 4 seconds

• Exhale through your mouth for 4 seconds

• Hold again for 4 seconds

• Repeat for several rounds

Resonant Breathing 

This is one of my go-to practices for balancing the nervous system.

• Inhale through your nose for about 5.5 seconds

• Exhale through your nose for 5.5 seconds

• Repeat for 5 to 10 minutes

CO2 Tolerance Drills 

I teach the exhale test for CO2 tolerance drills. After a gentle exhale, hold your breath and time how long it takes until you feel the first clear signal to breathe. This helps assess your current tolerance and track progress.

To train CO2 tolerance:

• Practice light breath holds after an exhale

• Stay calm and return to slow nasal breathing when done

• Gradually increase duration over time

These drills are powerful, especially when done consistently. They support endurance, recovery, and mental control.

Bringing Breathwork into Your Daily Life

You don’t need a long routine or complicated setup. A few minutes of breathwork at key moments during your day can make a big difference.

• Start your morning with resonant breathing

• Use box breathing during high-stress situations

• Wind down in the evening with slow nasal breathing or CO2 tolerance work

The key is to make it a habit and adjust based on how you feel. In my own practice, I cycle through different techniques depending on my goals that day.

👉Related Read: If you want to enhance your endurance, explore how breathwork supports athletic performance.

Want to Go Deeper?

If you're ready to train more intentionally, I offer breathwork courses to help you build a practice that fits your life. Whether you’re new to breath training or looking to refine your skills, I’ll walk you through methods that are grounded in science and experience.

Visit jesse coomer for upcoming sessions, online programs, and free resources. You can also find guided videos on my YouTube channel if you're just starting out and want to follow along.

Final Thoughts

Your breath is a tool. When you learn how to use it on purpose, everything begins to shift. You gain more control over your energy, your emotions, and your performance.

Start small. Stay consistent. Your breath is powerful. Learn to use it well.