The Body Does Not Lie
The Body Does Not Lie
FESBE 2026, breathing, HRV, EMG, EEG, and fNIRS in reading tensional selves
Before words, the body has already responded. Before justification, breathing has already changed. Before “everything is fine,” the jaw has already locked, the shoulder has risen, the chest has tightened, and attention has narrowed. The body regulates, compensates, stiffens, avoids, accelerates, or relaxes.
FESBE 2026 offers fertile ground for this discussion by connecting heart rate variability, biological rhythms, neurobiology, respiratory physiology, muscle disorders, metabolism, advanced technologies, and experimental methods. This is where BrainLatam2026 proposes a material reading of tensional selves.
A tensional self is a body-brain state in task. It appears when the body sustains a role: working, obeying, leading, smiling, selling, teaching, performing success, defending a belief, representing strength, or maintaining a family image. Each role has a physiological cost.
The thesis of this blog is simple:
tensional selves can be partially read through breathing, HRV/RMSSD, EMG, EEG, and fNIRS.
This reading expands how we listen to the body. It helps observe coherence, overload, rigidity, or the possibility of Zone 2.
Breathing is one of the first doors. When the body enters threat or intense social effort, respiratory rhythm changes. It may become short, shallow, irregular, or held. Voluntary slow breathing is associated with increased vagally mediated heart rate variability and modulation of emotional states, reinforcing breathing as autonomic regulation and interoception in action.
BrainLatam2026 proposes an important physiological hypothesis: many rigid tensional selves operate with short, high, non-diaphragmatic breathing. This pattern alters the dynamics between oxygen, carbon dioxide, and cerebral blood flow.
Under specific conditions of pause, sustained attention, or reduced excessive ventilation, CO₂ may rise from values close to 40 mmHg to around 45 mmHg. This moderate increase in CO₂ favors cerebral vasodilation, since CO₂ is central in regulating cerebral vessels; increased arterial CO₂ pressure dilates cerebral vessels and regulates cerebral blood flow.
In BrainLatam2026 language, this helps explain why slow breathing, silence, singing, prayer, fruition, contemplation, and bodily attention may favor Zone 2 through measurable autonomic, respiratory, and neurovascular pathways.
The hypothesis becomes more precise:
Zone 2 may involve respiratory and vascular reorganization that expands bodily listening, reduces hypercontrol, and favors greater prefrontal availability for metacognition.
HRV, especially RMSSD, helps observe autonomic flexibility. It indicates how the autonomic nervous system varies during a task. A body in Zone 2 tends to show greater regulatory flexibility; a body trapped in Zone 3 may show more rigid patterns, depending on sleep, nutrition, stress, general health, and context.
EMG shows where the social character is held in muscle. Jaw, face, trapezius, shoulders, and posture can carry the cost of “having to be.” Many tensional selves appear first in musculature. The “self that must endure” may appear in the trapezius. The “self that must remain silent” may appear in the jaw. The “self that must smile” may appear in the face. The “self that must control” may appear in breathing.
EEG listens to fast electrical dynamics: attention, conflict, error, vigilance, fatigue, surprise, and state changes. If the tensional self is a body in task, EEG helps observe the fine timing of that task. It shows when attention narrows, when control increases, when fatigue appears, and when the brain shifts from a flexible mode into a more rigid one.
fNIRS/NIRS complements this reading by observing cortical hemodynamic responses, especially in prefrontal regions. In naturalistic, social, and educational tasks, fNIRS can investigate cognitive load, control, decision-making, and regulation in environments closer to real life.
A BrainLatam2026 experimental design could compare three states:
body in a neutral task;
body in a demanding social role;
body returning to Zone 2 through breathing, pause, fruition, and metacognition.
During these conditions, we could measure breathing, HRV/RMSSD, jaw and trapezius EMG, EEG, fNIRS, GSR, posture, short self-reports, and bodily narrative of the experience.
The question would be:
which tensional self is being sustained now, and what is its physiological cost?
The same body that can enter Zone 2 can also learn to sustain extreme characters in Zone 3.
Some social roles — in military, financial, political, religious, corporate, or ideological contexts — may require a highly regulated social actor, capable of simulating empathy, modulating voice, controlling expressions, manipulating belonging, and inducing fear, hope, or obedience to achieve goals.
A rigorous formulation for this would be:
performative tensional selves of high social manipulation.
These selves may operate with high instrumental attention, low interoceptive listening, trained emotional control, simulated affect, strategic use of empathy, and the ability to capture “hearts and minds” without expanding collective consciousness.
Empathy research shows that empathic processes can be investigated materially, including event-related potentials in EEG during perceptual tasks. This allows emotional perception and social response to be studied without moralism.
In BrainLatam2026, the question is:
what kind of society rewards bodies trained to capture attention, affect, and belonging without producing collective Zone 2?
This is where EEG, fNIRS, HRV, breathing, GSR, EMG, and eye-tracking become relevant. These measures allow investigation of cognitive load, emotional control, hypervigilance, performative effort, muscle tension, autonomic response, and induced social synchronization.
The avatars enter here. Tekoha perceives the internal state: tightness, fatigue, safety, anxiety, comfort, or belonging. APUS observes posture, space, territory, and body in action. Iam helps name affect, motivation, and first-person experience. Math/Hep preserves methodological discipline: one hypothesis at a time, one measure at a time, one conclusion within the data.
The decolonial critique appears when we remember that Latin American bodies often need to sustain social characters that are too expensive: the always-available worker, the always-strong woman, the young person from the periphery always in defense, the Latin researcher always proving competence, the family always appearing harmonious, the religious person always certain, the politician always performing belonging.
Much rigidity is born from territory. It is born from inequality, environmental racism, precarious work, algorithms, economic insecurity, and a society that demands permanent representation.
For this reason, “The Body Does Not Lie” means that the body leaves material traces of its costs. Breathing, HRV, EMG, EEG, and fNIRS help us listen to what discourse often covers.
This also connects with DREX Cidadão. A society that reduces economic insecurity, hunger, extreme competition, and precarity reduces part of the pressure that pushes bodies into Zone 3. Citizen metabolism lowers the baseline cost of living while constantly representing survival.
In the end, the BrainLatam2026 question becomes:
when the body stiffens to sustain a character, what kind of society is demanding that role?
Recent References Supporting This Text
Laborde et al. (2022) — systematic review and meta-analysis on voluntary slow breathing and its effects on HRV, indicating influence on parasympathetic control and mental health.
Ogoh (2023) — review on cerebrovascular reactivity to CO₂, explaining that increased arterial CO₂ pressure dilates cerebral vessels and regulates cerebral blood flow.
Almeida et al. (2024) — systematic review on neural correlates of empathy in perceptual tasks using EEG event-related potentials.
Codina et al. (2025) — review on multimodal EEG-fNIRS fusion, highlighting possibilities and methodological cautions in combined analyses.
Chen et al. (2025) — study integrating fNIRS and eye-tracking to predict individual cognitive load using machine learning models.
Nandadeva et al. (2024) — study on cerebral vasomotor reactivity to CO₂, relevant for protocols investigating hypercapnia and cerebral blood flow.
