Rhythms form the foundation of biological life. From the steady beat of the heart to the natural cycles of respiration
and sleep, these repeating patterns help regulate communication and balance throughout the body. CranioSacral
Therapy (CST) focuses on one such rhythm—the CranioSacral Rhythm (CSR)—a subtle physiological motion
distinct from both cardiac and respiratory cycles. For more than four decades, CST practitioners have palpated this
rhythm as a guide to evaluate the body’s health and its ability to self-correct through gentle touch.
Earlier research tools lacked the sensitivity to measure the small micromovements associated with the CSR,
leading some to question whether this rhythm existed as a distinct physiological phenomenon. Today, modern
technology has confirmed the presence of a measurable, low-frequency rhythm averaging 4–8 cycles per minute—
separate from heart rate and breathing [1]. This discovery provides scientific support for what Dr. John E. Upledger
and countless CST practitioners have observed through palpation.
Dr. John E. Upledger and the Pressurestat Model
The modern understanding of the CranioSacral Rhythm began with Dr. John E. Upledger. As we have all heard,
during a surgical procedure in the 1970s, he noticed rhythmic movements of the spinal dura mater that could not
be attributed to the patient’s breathing or heartbeat. Intrigued by this observation, he began years of study into the
phenomenon and its potential physiological origins.
Dr. Upledger proposed what became known as the Pressurestat Model to explain these rhythmic motions [5]. He
theorized that cycles of cerebrospinal fluid (CSF) production and reabsorption created fluctuations in intracranial
pressure, producing gentle expansion and contraction of the cranial structures. He further suggested that these
rhythmic changes could be palpated throughout the body via the dural membranes and connective tissue system.
Importantly, Dr. Upledger emphasized that his model was not meant to be final. He recognized that as research
evolved, new scientific discoveries would provide greater clarity about the underlying mechanisms of the
CranioSacral Rhythm. His visionary openness to ongoing investigation laid the groundwork for future collaboration
between clinical practice and science. That willingness to evolve theory remains central to the Upledger Institute
International’s philosophy today.
Modern Research on the CranioSacral Rhythm
In recent years, scientific studies have confirmed that the CranioSacral Rhythm is indeed a measurable
physiological rhythm. A 2021 study by Rasmussen and Meulengracht identified a low-frequency oscillation distinct
from both cardiac and respiratory activity [1]. Using highly sensitive instruments, they recorded rhythmic cranial
motions averaging approximately 6 cycles per minute (range 4.25–7.07 cpm). The waveform pattern—consisting
of flexion, a neutral zone, and extension—mirrored the phases described by Dr. Upledger and CST practitioners.
The amplitude of this motion, around 58 micrometers, demonstrated that skilled palpation can reliably detect this
subtle rhythm.
Earlier research by Nelson, Sergueef, and Glonek also detected rhythmic oscillations in cerebral blood flow near
this same frequency using laser-Doppler flowmetry [2,3,4]. Together, these findings confirm that the rhythm
practitioners feel is not imaginary or coincidental—it reflects a genuine physiological process.
1
From Pressurestat Model to Pacemaker Theory
Building on Dr. Upledger’s foundational insights, modern neuroscience has expanded our understanding of
rhythmic activity in the body. The Pacemaker Theory, proposed by Thomas Rasmussen, PhD, MSc, CST-D, Upledger
Institute International’s Director of Research, presents a contemporary explanation for the CranioSacral Rhythm. It
aligns with Dr. Upledger’s vision by integrating clinical experience with current knowledge of neurophysiology.
The Pacemaker Theory suggests that the CSR arises from specialized networks of oscillating neurons in the
brainstem near the fourth ventricle, much like those that create cardiac and respiratory rhythms [6–8]. These
neurons act as biological pacemakers, generating rhythmic electrical impulses that are independent of respiration
and heart rate. Their output influences vascular tone and fluid dynamics through a process known as neurogenic
vasomotion—the rhythmic contraction and relaxation of blood vessel walls driven by neural activity [11,12].
These neural rhythms are transmitted throughout the body via the Autonomic Nervous System (ANS) and
coordinated by the Central Autonomic Network (CAN), which links the brainstem, hypothalamus, and higher
cortical regions [11]. The CAN helps synchronize activity across multiple body systems, maintaining homeostasis
and dynamic balance. Within this framework, the CSR can be seen as one of the body’s neurogenic rhythms—an
expression of the brainstem’s pacemaking activity conveyed through vascular and connective tissue pathways. This
understanding expands upon Dr. Upledger’s Pressurestat Model by offering a new perspective on cause and effect.
The Pressurestat Model proposed that cerebrospinal fluid (CSF) production and reabsorption generated the
rhythmic motion perceived in the CranioSacral System. At the time, this explanation reflected the scientific
knowledge and measurement technology then available—direct observation of neural rhythmicity was not yet
possible. Advances in neuroscience and imaging have since revealed that rhythmic neural activity within the
brainstem can act as a biological pacemaker, producing oscillations that drive CSF movement rather than being
driven by it. In this way, the Pacemaker Theory builds on Dr. Upledger’s foundational insight, providing a
contemporary neurophysiological framework for the rhythm he so carefully described.
2
The Body’s Built-In Rhythms
Human physiology depends on internal pacemakers that regulate rhythmic processes such as breathing, heartbeat,
and digestion. These pacemakers are clusters of neurons that produce self-sustaining rhythms even without
external stimuli [6–9]. Each rhythm maintains a baseline frequency yet remains flexible to respond to changing
demands. When disrupted, these rhythms can affect multiple body systems and overall health [10].
The CranioSacral Rhythm may function similarly—as a low-frequency neurogenic rhythm contributing to
homeostasis and balance. Variations in its quality or amplitude may reflect shifts in autonomic tone, stress
responses, or tissue restriction. By gently engaging with this rhythm, CST practitioners work in concert with one of
the body’s intrinsic regulatory systems.
Integrating Science and Practice
For Upledger alumni, the evolution from the Pressurestat Model to the Pacemaker Theory represents the
continuity of Dr. Upledger’s vision: that future research would refine and expand understanding of the
CranioSacral System. The emerging evidence for brainstem pacemakers and neurogenic vasomotion provides a
plausible scientific context for what practitioners have long felt through their hands.
Dr. Upledger taught that only about 5 grams of pressure—the weight of a nickel—was needed to engage with the
body’s natural rhythms. This gentle touch reflects how the CranioSacral System itself functions—subtle, rhythmic,
and responsive. Through that light contact, practitioners can support the body’s ability to regulate, balance, and
heal itself.
The Pacemaker Theory offers a thoughtful bridge between hands-on experience and modern science,
demonstrating how clinical observation and research continue to inform and refine one another. In honoring Dr.
Upledger’s legacy, we recognize that science does not replace intuition—it deepens it. While the Pacemaker Theory
remains an evolving scientific model, it provides a plausible framework for understanding the CranioSacral
Rhythm as a neurogenic, system-wide phenomenon. This perspective reinforces that CranioSacral Therapy works
in harmony with the body’s innate intelligence and its rhythmic foundation of life.
References
1. Rasmussen TR, Meulengracht KC. Direct measurement of the rhythmic motions of the human head identifies a
third rhythm. J Bodyw Mov Ther. 2021;26:24–29.
2. Sergueef N, Nelson KE, Glonek T. The palpated cranial rhythmic impulse (CRI): Its normative rate and examiner
experience. Int J Osteopath Med. 2011;14(1):10–16.
3. Nelson KE, Sergueef N, Glonek T. Laser-Doppler flowmetry and cranial rhythmic impulse. J Am Osteopath
Assoc. 2001;101(9):457–466.
4. Nelson KE, Sergueef N, Glonek T. Recording the rate of the cranial rhythmic impulse. J Am Osteopath Assoc.
2006;106(6):337–344.
5. 6. Upledger JE, Vredevoogd JD. CranioSacral Therapy. Seattle: Eastland Press; 1983.
Marder E, Bucher D. Central pattern generators and the control of rhythmic movements. Curr Biol.
2001;11(23):R986–R996.
7. Feldman JL, Del Negro CA. Looking for inspiration: new perspectives on respiratory rhythm. Nat Rev Neurosci.
2006;7(3):232–242.
8. Monfredi O, Boyett MR. Sick sinus syndrome and atrial fibrillation in older persons – role of sinoatrial node,
atrial fibrosis, and aging. Heart Rhythm. 2015;12(4):1089–1097.
9. Glass L. Synchronization and rhythmic processes in physiology. Nature. 2001;410(6825):277–284.
10. Buzsáki G, Draguhn A. Neuronal oscillations in cortical networks. Science. 2004;304(5679):1926–1929.
11. Benarroch EE. The central autonomic network: Functional organization, dysfunction, and perspective. Mayo
Clin Proc. 1993;68(10):988–1001.
12. Julien C. The enigma of Mayer waves: Facts and models. Cardiovasc Res. 2006;70(1):12–21.
Written by
Thomas Rasmussen, Avadhan Larson, Dawn Langnes Shear
Upledger Institute International
About the Authors
Thomas Rasmussen holds a PhD in Medical Science, an MSc in Chemistry, and BSc degrees in Biochemistry and
Biology. He serves as Director of Research for the Upledger Institute International, bringing over 30 years of
experience in scientific research and evidence-based medicine to the field of manual therapy. Based in Finland, he
teaches internationally across the Upledger CranioSacral Therapy curriculum, integrating the Upledger Paradigm
in clinical practice while leading research, curriculum innovation, and advanced education worldwide.
Dawn Langnes Shear serves as Chief Development Officer and Co-Chief Executive Officer for the Upledger and
Barral Institutes. A 33-year team member with a background in health sciences and massage therapy, she leads
global development, scientific initiatives, and partnerships across 70 countries. She directs publishing, product
innovation, and research collaboration and serves on the Integrative Health Policy Consortium, advancing
evidence-informed, integrative healthcare education worldwide.
Avadhan Larson, LAc, LMT, CST-D, RCST, SEP is a Senior Instructor for the Upledger Institute International and a
Diplomate Certified CranioSacral Therapist with more than 35 years of clinical and teaching experience. Based in
Colorado Springs, Colorado, she teaches internationally throughout the Upledger CranioSacral Therapy curriculum,
including SomatoEmotional Release, Pediatrics, Advanced CST, and The Brain Speaks. A Licensed Acupuncturist
and Certified Somatic Experiencing Practitioner, Avadhan integrates trauma resolution, pre- and perinatal work,
and compassionate presence into her clinical practice and global teaching, furthering the legacy of Upledger
CranioSacral Therapy worldwide.