From the R of the QRS to the Brain: The Heartbeat as Information
From the R of the QRS to the Brain: The Heartbeat as Information
Series: Breathing, Body, Consciousness, and the Shifting of the Tensional Selves (Eus Tensionais)
Introduction — Brain Bee (first-person consciousness)
As I sit here, my heart is beating.
But it doesn’t beat only to move blood.
Between one beat and the next, something in me knows an event has happened—
not as a thought, not as an emotion—
but as a silent landmark.
Before I consciously notice anything,
my brain has already been informed.
My heart marks the time of feeling.
The QRS and the R-peak: far beyond mechanics
On the electrocardiogram, the QRS complex represents ventricular depolarization.
Within it, the R-peak is the point of greatest electrical amplitude.
Traditionally, it is treated as:
a technical marker,
a cardiac electrical event,
a point for measuring RR intervals.
But physiologically, the R-peak is a high-precision temporal signal sent to the whole body.
It happens:
with every heartbeat,
with variable regularity,
in synchrony with breathing, blood pressure, and autonomic state.
From heart to brain: the HEP
The brain does not ignore the heart.
After each R-peak, measurable brain responses emerge, known as Heartbeat-Evoked Potentials (HEP).
These potentials:
occur tens to hundreds of milliseconds after the R-peak,
are recorded with EEG,
vary with bodily and attentional state.
This reveals something fundamental:
the heart informs the brain beat by beat.
The heartbeat as information, not only perfusion
The heart:
pumps blood (hemodynamic function),
but alsomarks rhythm (informational function).
Each R-peak provides the brain with:
a time signal,
a predictable internal event,
a reference point for sensory integration.
This information contributes to:
bodily consciousness,
the sense of presence,
the perception of continuity of the “self.”
HEP, interoception, and feeling
HEP amplitude and pattern:
vary with autonomic state,
change with attention to the body,
shift in anxiety, dissociation, or fruition-like states.
When interoception is open:
the brain responds more clearly to the heartbeat,
the HEP tends to be more defined.
When the body is in defense:
the HEP changes,
internal perception becomes poorer.
This is not “psychological.”
It is physiological coupling.
Breathing, HRV, and the quality of the cardiac signal
The R-peak does not occur in isolation.
It sits inside a context that is:
respiratory,
autonomic,
metabolic.
When HRV is rich and variable:
RR intervals shift with breathing,
the brain receives living rhythmic information.
When HRV becomes impoverished:
signals become too predictable,
the brain loses temporal richness.
To vary cardiac rhythm
is to vary the information reaching the brain.
Tensional Selves and cardiac reading
Each Tensional Self:
sustains an autonomic pattern,
shapes HRV,
alters HEP patterns.
A Self of alertness:
tends to reduce variability,
impoverishes the heart–brain dialogue.
A Self of fruition:
expands variation,
supports interoceptive integration.
The heart reveals which Self is in command.
The heart as a metronome of feeling
Bodily sensations do not arise in a vacuum.
They organize around repetitive internal events.
The R-peak functions as:
an internal metronome,
a marker of continuity,
a temporal anchor for feeling.
That’s why changes in heart rhythm:
alter time perception,
alter the sense of presence,
alter bodily awareness.
When the dialogue is lost
In chronic stress or rigid ideology:
the heart moves into repetitive patterns,
HRV drops,
HEP richness diminishes.
The brain keeps operating,
but it listens less to the body.
Dissociation begins in rhythm,
not in narrative.
Recognizing this in your own body
Without measuring—just sensing:
Can I feel my heartbeat at rest?
Does it change with my breathing?
Is there a sense of inner continuity?
Does my feeling track the rhythm, or does it seem disconnected?
These perceptions are echoes of the heart–brain dialogue.
Closing
The heart is not only a pump.
It is a rhythmic transmitter of information.
The R-peak of the QRS marks the brain’s time,
organizes feeling,
and sustains bodily consciousness.
Where there is variation, there is dialogue.
Where there is rigidity, the signal becomes poorer.
To understand the heart
is to understand how the body informs the mind.
This text is part of the series Breathing, Body, Consciousness, and the Shifting of the Tensional Selves (Eus Tensionais), where different aspects of the same living system are approached from complementary angles.
References (post-2020)
Park, H. D., et al. (2020). Neural Responses to Heartbeats and Conscious Awareness. Journal of Neuroscience.
→ Demonstrates the existence and variability of HEP as a neural basis of cardiac interoception.
Candia-Rivera, D., et al. (2021). Cardiac Signals and Conscious Processing. NeuroImage.
→ Shows how cardiac signals modulate conscious processing in the brain.
Azzalini, D., Rebollo, I., & Tallon-Baudry, C. (with post-2020 updates). Visceral Signals Shape Brain Dynamics. Trends in Cognitive Sciences.
→ Grounds the influence of rhythmic visceral signals on brain organization.
Coll, M. P., et al. (2021). The Heartbeat-Evoked Potential and Self-Related Processing. Biological Psychology.
→ Links HEP to the perception of the bodily self.
Allen, M., et al. (2021). Unexpected arousal modulates the heartbeat-evoked potential. Journal of Neuroscience.
→ Demonstrates how autonomic states alter the brain’s response to the heartbeat.
Forte, G., et al. (2022). Heart Rate Variability and Interoceptive Brain Responses. Neuroscience & Biobehavioral Reviews.
→ Integrates HRV, RMSSD, and heartbeat-evoked brain responses.
Thayer, J. F., et al. (2021). Neurovisceral Integration and Cardiac-Brain Communication. Biological Psychology.
→ Supports a bidirectional model of heart–brain communication.
Park, G., et al. (2022). Cardiorespiratory Phase Modulates Neural Excitability. Frontiers in Neuroscience.
→ Shows how cardiac and respiratory rhythms modulate brain excitability.
