“What must be taught first is breathing.” —Confucius

It is somewhat alarming how much of our body is under autopilot. But given how easily distracted humans are, that’s definitely a good thing. If we had to remember to make our heart beat every single second, we wouldn’t make it to breakfast. Simple distractions like cat videos would be deadly. So, evolution wisely opted to give all of our organs their own control center. It sounds gross, but the heart still beats even when you cut it out of the body. The gut will still gurgle and pulse even if it gets disconnected from the brain.

These independent control centers are all coordinated by your autonomic nervous system that has two parts, fright and fun. The frightening part is the sympathetic system that powers the flight or fight mode and communicates through your spinal cord. The fun part is the parasympathetic system that powers the feed and breed mode, followed by resting and digesting. It is definitely the party system, and it communicates through the vagus nerve.

The autonomic exception

There is one exception to this autopilot program: you can take control of your breathing. That grants you some unexpected leverage over your stress: When you inhale, your frightening sympathetic system kicks in, and when you exhale, your fun parasympathetic system takes over. This is greatly simplified — we’re talking about biology after all — but that is the current understanding in broad strokes.

Breathing quickly is a pretty reliable way to pump up your system for a fight. And most people have heard that slow breathing can calm you down. But a specific mix of deep inhalation with long exhalation can have an even greater impact on your stress levels. Here’s how it works.

When you inhale deeply, cortisol levels rise. There is a corresponding rise in blood pressure and heart rate. Extra oxygen is delivered to your body and brain. This is how you’re going to outrun that guy with a knife or fight off an attacking dog.

When you exhale, your vagus nerve is activated, pushing you into the rest and digest mode. Cortisol levels drop, your heart slows down and your blood pressure drops. You chill. The longer you exhale, the greater the effect. So, if you breathe in deeply and then blow out slowly, you get more of the chill mode and less of the scary mode.

Because at least half of the effect of deep-breathing exercises involves the vagus nerve, it is not too surprising that it can increase vagal activity. It is a little more surprising that it can also improve symptoms of IBS. Deep breathing increases oxygen levels all through the digestive system, helping to keep the gut lining healthy and able to better deter pathogens.

Breathing 101

Try it now: Breathe in deeply for three to four seconds. You can breathe in through your mouth, but breathing in through the nose brings an extra bonus: you inhale the nitric oxide that is produced by your sinuses. Nitric oxide dilates blood vessels which helps to lower your blood pressure, so you get an extra dose of tranquility with each nasal inhalation.

After breathing in deeply, purse your lips and very slowly let your breath out, for eight seconds or longer if you can. Right away, your cortisol drops, your heart slows, and your blood pressure drops. Your systolic pressure can drop by up to 10 points. Stress is relieved. For lack of a better term, we’ll call this 4-8 breathing.

If you have stage 1 hypertension, with a systolic reading from 130 to 139, some doctors believe that breathing exercises can work as well as medication. The reduction in blood pressure can even exceed what you get from traditional aerobic exercise.

That drop in stress reactivates a healthy immune response and lowers inflammation, which is good for all your organs, including your gut and its microbial denizens. Studies find that 4-8 breathing decreases gut pain and leads to more regular bowel movements. Deep breathing can even reduce IBS symptoms. It can start a virtuous cycle with your microbiome, ultimately leading to better mood and robust resilience.

Try it!

The next time you go to the doctor, have your blood pressure taken before and after you use 4-8 breathing. You’ll find that it’s surprisingly effective, and the result lasts for hours. If you make it a habit, it can have a more permanent impact. Studies show that extended breathing exercises with just 30 breaths a day can lower blood pressure, even weeks after stopping. You can do that in about six minutes a day.

You might find exercise too troublesome and meditation too mystical — but breathing a little differently doesn’t seem like a big ask. Give this powerful health hack a try, especially if you have high blood pressure.

This simple technique can also help you get to sleep faster at night. Three or four of these de-stressing breaths can take the edge off an active mind and calm you down for sleep. In fact, deep breathing can bulk up your respiratory muscles and may help with apnea, for a doubly good night’s sleep.

It is amazing that nature provides us with this tool, but frustrating that more people don’t know about it. Be a friend and pass it on.

References

Institute on Drug Abuse, Toxicology and Pharmaceutical Science, School of Health Sciences, Ege University School of Health Sciences, İzmir, Türkiye, Güneş Schareck, Sedat Çapar, Department of Statistics, Dokuz Eylül University Faculty of Science, İzmir, Türkiye, Wolfgang Schareck, and Breath Academia, İzmir, Türkiye. “Conscious Awareness-Based Breathing Method on Perceived Stress, Salivary Cortisol Level and Alcohol Craving.” ADDICTA: The Turkish Journal on Addictions 11, no. 3 (2025): 249–56.

Kim, Sang Hwan, Suzanne M. Schneider, Margaret Bevans, et al. “PTSD Symptom Reduction With Mindfulness-Based Stretching and Deep Breathing Exercise: Randomized Controlled Clinical Trial of Efficacy.” The Journal of Clinical Endocrinology & Metabolism 98, no. 7 (2013): 2984–92.

Obaya, Hany Ezzat, Heba Ahmed Abdeen, Alae Ahmed Salem, et al. “Effect of Aerobic Exercise, Slow Deep Breathing and Mindfulness Meditation on Cortisol and Glucose Levels in Women with Type 2 Diabetes Mellitus: A Randomized Controlled Trial.” Frontiers in Physiology 14 (July 2023).

Örün, Deniz, Selma Karaca, Şükran Arıkan, Deniz Örün, Selma Karaca, and Şükran Arıkan. “The Effect of Breathing Exercise on Stress Hormones.” Cyprus Journal of Medical Sciences, ahead of print, Cyprus Journal of Medical Sciences, June 1, 2022.