According to yoga, energy flows more freely through the heart when we breathe into it and focus our attention on that area – energy flows where attention goes. Breathing is directly linked to and directly affects the heart. The regular practice of diaphragmatic breathing significantly improves heart rate variability and coherence. All dynamics of the heart are improved when we breathe correctly. The more a person improves their heart rate variability (HRV) the healthier they become. This is good for ischemic heart patients who have diabetes. Heart rate variability is indispensable in distinguishing healthy subjects from patients with cardiovascular disease.
Heart rate variability (HRV) is an indicator of the cardiac autonomic control. Yogic, or what is known as belly breathing (deep abdominal breathing vs. shallow rib cage breathing), modifies the autonomic status by increasing sympathetic activity (reduced vagal activity). Its uncanny how accurately low HRV scores and trends align with illness.
Ancient yoga breathing techniques not only regulate the heart but also stimulate and increase vital energy, strengthen internal organs and thus regenerate and rejuvenate the body. Through breathing consciously, we can achieve the optimal functioning of the endocrine, nervous, digestive and other bodily systems, and gain mental and physical stability.
When your exhale is even a few counts longer than your inhale, the vagus nerve sends a signal to your brain to turn up your parasympathetic nervous system and turn down your sympathetic nervous system. The sympathetic system commands our fight or flight response, and when it is stimulated it increases heart rate and breathing, and also increases stress hormones like cortisol. The parasympathetic system, on the other hand, controls your rest-relax-and-digest response. When the parasympathetic system is dominant, your breathing slows, your heart rate drops, your blood pressure lowers as the blood vessels relax, and your body is put into a state of calm and healing.
Mantak Chia wrote, “For thousands of years Taoist masters have taught natural breathing. We are able to improve the functioning and efficiency of our heart, lungs, and other internal organs and systems. We are able to help balance our emotions. We are able to transform our stress and negativity into the energy that we can use for self-healing and self-development. And we are better able to extract and absorb the energy we need for spiritual growth and independence.” Breathing correctly is important for living longer and it helps us to maintain positive emotions as well as helping keep our performance at its best in everyday activity.
We all breathe, all day, every day, so we might as well do it right. Since a breath is the very first and last physical activity we undertake in life, we should give it the consideration and importance it deserves in our pursuit of health and relaxation. We can live a long time without food and a couple of days without drinking, but life without breath is measured in minutes. It seems that unless one participates in yoga, breathing does not get the attention it deserves.
As soon as we pay attention to our breathing, it immediately changes, and that is the whole point. Breathing retraining entails bringing our awareness to our breath and to treat with respect something that is so important to maintaining our lives.
Crystal Tatum says, “Breathe. Just breathe. It’s so simple; it can’t possibly help, can it? What do you mean just breathe? Of course I’m breathing! What a dumb thing to say. I have the good fortune of being friends with a lot of highly-evolved folks who know a thing or two about helping the not-so-highly evolved such as myself. But when one of those friends said to me one day, “Don’t forget to breathe,” I couldn’t help but cock an eyebrow and give her a “What the heck are you talking about?” look. She told me I was holding my breath. I thought she was nuts, but the next time I found myself angst-ridden, I took notice of my body and realized she was right. Since then, I’ve noticed that I tend to do that when I’m highly stressed or anxious. I clench my jaw and hold my breath, taking only the shallowest inhalations when necessary. This response only heightens my stress and keeps me on edge. I’ve learned a few breathing techniques since then that really do ease my tension.”
Dennis Lewis, the author of the Tao of Breathing wrote, “In 1990 I found myself physically, emotionally, and spiritually exhausted, with a constant, sharp pain on the right side of my rib cage. When Gilles Marin first put his hands into my belly and began to massage my inner organs and tissues, and when he began to ask me to breathe into parts of myself that I had never experienced through my breath, I had no idea of the incredible journey of discovery that I was beginning. Though the physical pain disappeared after several sessions, and though I began to feel more alive, a deeper, psychic pain began to emerge—the pain of recognizing that in spite of all my efforts over many years toward self-knowledge and self-transformation, I had managed to open myself to only a small portion of the vast scale of the physical, emotional, and spiritual energies available to us at every moment. As Gilles continued working on me, and as my breath began to penetrate deeper into myself, I began to sense layer after layer of tension, anger, fear, and sadness resonating in my abdomen below the level of my so-called waking consciousness, and consuming the energies I needed not only for health, but also for a real engagement with life. And this deepening sensation at the very center of my being, painful as it was, brought with it an opening, not only in the tissues of my belly, but also in my most intimate attitudes toward myself, a welcoming of hitherto unconscious fragments of myself into a new sense of discovery.”
 Arq Bras Cardiol. 2009 Jun;92(6):423-9, 440-7, 457-63. Effect of diaphragmatic breathing on heart rate variability in ischemic heart disease with diabetes.