Take a deep breath in

How Our Lungs Communicate with the Brain

Have you ever noticed how a deep breath can instantly bring a sense of calm? This isn’t just a psychological effect, it’s kind of magic but not, it's a natural response that is rooted in the intricate communication between our lungs and brain. Yoga practices have noticed this for a long time, so let's see what's going on when we take a deep breath in.

The Journey of a Breath

When we inhale deeply, our lungs expand, stretching the smooth muscles in our airways. This expansion activates specialised sensors known as pulmonary stretch receptors in the lungs. These receptors are sensitive to the degree of lung inflation and play a crucial role in regulating our breathing pattern and can even influence the Vagus nerve, which is responsible for switching us between excitable and relaxed modes (see zones of regulation below). I always mention in class that feeling bored can be a sign of a shifting nervous system.

These zones of regulation used in primary schools is an excellent way of learning about nervous system responses (Source: Komodo Wellbeing)

To prevent over-inflation of the lungs, the body employs the Hering–Breuer reflex. When pulmonary stretch receptors detect excessive stretching during a large inhalation, they send signals via the vagus nerve to the brainstem. These signals inhibit further inhalation, prompting the body to exhale. This reflex ensures that our lungs operate within safe limits, maintaining optimal respiratory function. In other words, there's only so deeply you can breathe in before your body automatically puts a stop to it. Holding your breath at the top of an inhale implicated in the regulation of health airway muscles, the regulation of good heart health, and avoidance of restrictive lung diseases.

Breathing and the Nervous System

The interaction between pulmonary stretch receptors and the brainstem highlights the deep connection between our respiratory and nervous systems. By understanding this relationship, we can appreciate how conscious breathing practices, like Pranayama, influence our overall well-being.

Visualizing the Connection

To better understand this physiological process, here’s a diagram illustrating the pathway of signals from the lungs to the brain:

This diagram shows how the pulmonary stretch receptors in the lower airways (ASM - airway smooth muscle) detect lung expansion during a deep breath. When the lungs stretch too much, the receptors send a signal via the vagus nerve (Vagus N.) to the brainstem—specifically the nucleus tractus solitarius (NTS) in the medulla oblongata and the apneustic center (NPA) in the pons which is responsible for breath regulation and is the brain-body relay device (Source: Schelege, 2002).

The brain processes this signal and sends a response back down to the diaphragm and respiratory muscles via spinal motor neurons (SMN), signaling the lungs to stop inflating and to begin exhaling. This automatic safety mechanism, known as the Hering–Breuer reflex, helps prevent lung over-expansion and maintains smooth, rhythmic breathing.

By tuning into our breath and understanding the body’s natural mechanisms, we can harness the power of conscious breathing to enhance our physical and mental health.

Stay tuned for our next entry, where we’ll explore the nuances of exhalation and its impact on the body.

Why Is This Important for Pranayama?

Understanding how your lungs and brain work together can make breathwork feel a little less mysterious. When practicing Pranayama or any deep breathing exercises, you might notice that moment when your body naturally pauses before exhaling. That’s your pulmonary stretch receptors doing their job!

By becoming more aware of this natural rhythm, you can feel more in tune with your body and more confident in your practice. It’s like learning the choreography of your own breath, one that your body has been performing instinctively your whole life.

A Practical Takeaway

Next time you practice deep breathing, notice the point where your inhale naturally pauses. Instead of forcing a longer breath, let your body take the lead. Trust that your brain and lungs are already working in harmony to keep you safe and balanced.