Taking shallow breaths into the chest, as opposed to taking full diaphragmatic breaths, restricts the movement of the diaphragm and undermines the lung capacity. If you are wondering what a better way to breathe looks like, you can take a look at new-born babies. New-borns fully engage their diaphragm muscle when breathing — just observe how their bellies rise and fall with each breath.
However, as we approach adulthood, we tend to become chest breathers. We utilize our diaphragm less. We learn to hold our breath in stressful moments. Due to both environmental and personal factors such as pollution, anxiety, the desire to have a flat stomach, we reduce our breathing capacity and slowly get away from our natural breath.
Taking shallow, frequent breaths triggers the stress response in the body, activating the fight-or-flight state. As shallow breathing becomes a habit, the stress response may also gradually become a habit, keeping our sympathetic nervous system activated for longer periods. So, shallow breaths trigger stress and stress triggers shallow breaths. This vicious cycle leads to many problems such as headaches, insomnia, fatigue, panic attack and muscle pain. Chronic stress linked to shallow breathing can also compromise the immune system and trigger cardiovascular conditions.
On the other hand, deep diaphragmatic breathing can help us calm down both our body and mind. It is extremely helpful in managing stress, lowering blood pressure, reducing heart rate, relaxing muscles, and improving concentration.
It should be kept in mind that shallow breaths are used in some breathing exercises and there is no ideal breathing pattern that works for everyone, all the time.