Your body is made up of 50–70% water. Think about that for a moment. We typically think of ourselves as solid, as tissue and bone. But we’re not—we’re mostly liquid. We’re more like islands of interconnected tissue and bone floating in an inner sea.

In essence, the body is like a giant, fluid-filled sac. And it doesn’t take much to get the fluids in that sac to rock. Indeed, the movement of our inner sea is not so different from its oceanic roots. It has faster waves near the surface and slower, deeper tides. When I put my hands on a body as a craniosacral therapist, or tune in from a distance, I can feel those waves and tides.

Feeling the fluid tide

The fluid tide is one of the body’s natural biorhythms, like your heartbeat or breathing. It wells upwards toward the head, while also slightly widening and flattening the body. Then after 10–15 seconds, it recedes downwards toward the feet, while also subtly narrowing and deepening the body.

This tide is often most clearly perceived in the head and spine, in the slow up-and-down movement of cerebral spinal fluid. But it can also be felt as a gentle rolling outward and inward of the arms and legs, or as a subtle ballooning and deflating of tissues anywhere on the body.

What makes the fluid tide move?

Some practitioners describe a pressurestat model, a semi-closed, hydraulic system contained by the dural membranes surrounding the brain and spinal cord. They posit that pressure changes caused by the production and reabsorption of cerebral spinal fluid create the motion. However, these motions can be felt through all the fluids of the body, not just in the spine, and they continue even if the dural tube is surgically cut, breaking the pressure seal.

Other practitioners believe it’s the spark in the fluids that causes the movement. They describe a vital, life force energy that moves through and enlivens the fluids. This spark is most concentrated in the cerebral spinal fluids—like liquid light. And it’s this vital life force, they say, that engenders the rhythmic motion in the fluids. 

Listening to the tide (and its spark)

I can’t yet say from personal felt-experience what makes the fluid tide move—that might take a lifetime. But I can feel that spark, the powerful energy pulsing and flowing within the fluids. And when I sit in stillness, tracking and following the tide and its liquid light within a person, powerful healing responses awaken. In next month’s article, I’ll talk about this innate, self-healing mechanism—how the energy and fluids work to repair and heal our tissues, emotions, and psyches.