Shiva Rea is known for bringing yoga to life and making it accessible to modern practitioners. She has studied many forms of yoga and dance in India, Africa, Nepal, Jamaica, and Bali and has been practicing and teaching for more than 17 years. In her newest book, Tending the Heart Fire: Living in Flow with the Pulse of Life (Sounds True), Shiva combines meditation, rituals, and everyday practices drawn from around the world, including yoga, Ayurveda, Tantra, and recent scientific breakthroughs, to create a guide to becoming what she calls “a firekeeper of the sacred heart.”

According to Shiva, “Modern firekeepers tend their lifeforce in many forms. They are artists, activists, teachers, musicians, scientists, healers, and entrepreneurs. They are mothers, fathers, sisters, and brothers. Love, devotion, and skill are required to keep such fires flourishing. We must embody fuel, fire, and firekeeper all at once to realize the extraordinary creative force that burns within us.”

In this excerpt from her book, she writes about the relationship between our hearts and our brains and how to harmonize them.

Embodying the Heart Fire: The Science of the Energetic Heart

The great conductor of the body’s rhythms is the pulse of the heart. The heart is the only organ made of specialized cells—cardiac cells—with the unique capacity to create a pulsing electrical charge. This charge in turn creates a vast electromagnetic field of energy. As the most powerful “rhythm maker” of the body, the heart has the ability to govern all of the body’s other rhythms.

Throughout our lives the heart sends more signals to the brain than vice versa. Although we may perceive a split between heart and brain, they love to be in synch. When our brainwaves and heart rhythms come into a state of entrainment, or “heart-brain coherence,” we are at our highest state of energy flow, physically, mentally, and emotionally.

With the intellectual understanding that heart and brain synchronize naturally, we can begin to feel this coherence as a natural state of yoga. And we can see how ancient meditations and other practices—focused attention, breathing in rhythm, chanting, music, movement—facilitate alignment between the two. This is the science at work when we tend the energetic heart or Heart Fire in meditation.

The heart is where the body senses new information first. Then, with every beat, it relays a burst of neural activity to the medulla, located at the base of the brain, via the vagus nerve and nerves in the spinal column—the same pathways that carry pain and other feeling sensations to the brain. Energy, or information that vibrates, constantly flows between heart and brain, assisting us in our emotional processing, sensory experience, ability to derive meaning from events, and reasoning.

When we shift our focus to the heart and away from the brain, large populations of cells in the forebrain entrain to the heart’s rhythms. There is a tremendous ripple effect that we can noticeably perceive as the first sign that our awareness of our heart’s energy has begun. Mental dialogue is reduced. Messages flow freely and directly between the heart and brain through the sympathetic and parasympathetic nerve pathways, as well as the baroreceptor system (sensory nerves in the arteries). Connectivity increases between brain and body, and neuronal firing increases. Greater heart-brain entrainment allows a person to function at higher states, which can be consciously practiced through intentional focus on the heart.

Stress Rhythms and the Healing Power of Attention

We often experience stress when we’ve lost our ability to navigate transitions in a fluid and healthy way. With any transition there is a natural fluctuation, a healthy chaos, a variation to the flow, a change in the fire. Fluctuations are actually positive things; they have the ability to reset the vibrational patterns in our hearts. But they also create a vulnerability that we must tend to on all levels so that these transitions don’t agitate or dim the flow of our life force. We need to feel for signs of disruption in the heart field affecting our emotions, insights, actions, or speech.

When brainwaves and heart rhythms are out of synch, inefficiency is introduced into the system and the entire body experiences further stress. But we can bring consciousness to this cycle. Pay attention to the arising dissonant rhythms in your heart—experienced as tension, emotional stirring, pressure, impatience, or a sense of holding, being overwhelmed, or out of synch. These are often the first signs of negative stress, and whether these sensations are large or small, they signal that something needs to change to bring you back into balance.

When we attune to the pulse of the heart, we become able to sense subtle movement toward stress and we can make a conscious shift toward balance. We can develop our own unique healthy heart rhythms and shift into more “solar” or “lunar” modes of being, from fully expressive to quiet and reflective. By tuning in to the heart in this deep and nuanced way, we can create the openness and flexibility that remove constrictions around the heart.

Slower heart rhythms alter brainwave frequencies in such a way that deeper states of being can occur. At the deepest levels of entrainment, our brainwaves and heart rhythms are in synch with every other cell in the body, creating a field of energy that extends beyond it. The strength of this field literally depends upon how aware of and connected to the heart we are.

If we are aware of how damaging “disconnected stress” is to our system and, in contrast, how powerfully regenerating the state of love is for our whole being, we will be more aware of which “fire” we are fueling.

Only by reclaiming our fire-tending—on the altar, in the hearth, and in the pulsing fire that burns in our center—can we reconnect to natural rhythms within and reverse these modern trends. And it is not hard to do. Light a single candle and watch the small flame dance for a moment. You have begun.

Beat by beat, our hearts are patiently requesting that we return to the natural flow of life. The message is clear. Sometimes, in fact, the heart speaks more clearly than we are ready to hear, sparking the brain’s expert ability to rationalize and resist change. Yet the heart’s mystic force continues to invite us to inhabit our core selves: our truth, our longing, and our deepest passions. Even if we have distanced ourselves from its rhythms for a long time, the moment we place our attention there, it will always welcome us again.

Adapted from Tending the Heart Fire: Living in Flow with the Pulse of Life, by Shiva Rea. Copyright © 2013 Shiva Rea. Published with permission from Sounds True.