The Body Arrives Before the Decision -  Menstrual Pain as a Hidden Modulator of Brain Connectivity

When we think about performance, attention, or decision-making, it is common to imagine that the brain begins each task from a relatively neutral point, and that differences only emerge after a stimulus arrives.

But before movement, before competition, and before any response that we can consciously narrate, there is a body in a particular physiological state.

And that state may already participate in how brain networks are organized.

Main Reference

The starting point for this reflection is the publication by Carina Pohle, Daniel Büchel, Silvana Bucher Sandbakk, Øyvind Sandbakk, Belinda Pletzer, and Jochen Baumeister (2026), “Uncovering a hidden modulator for women in sports: An exploratory study of menstrual pain and brain connectivity,” published in Women’s Health.

It is a scientific initiative that deserves particular recognition.

Rather than reducing the discussion to the recurring question of whether a certain phase of the menstrual cycle improves or impairs performance, Pohle and colleagues introduce a variable that may remain hidden when researchers look only at hormones or calendar phases: the experience of menstrual pain.

The authors themselves point out that menstrual health, contraceptive use, and pain have historically received insufficient attention in research involving female athletes. Their study therefore investigates whether resting-state functional brain connectivity differs across phases of the menstrual cycle and combined oral contraceptive use, and, importantly, what happens when pain intensity is incorporated into the analysis.

The value of this initiative also lies in avoiding a deterministic interpretation of female physiology. The results are more interesting than a simple conclusion such as “phase A is different from phase B.”

Instead, the study opens another question:

What if a bodily variable that we are not sufficiently observing is changing what we measure in the brain?

What Did the EEG Reveal?

The study followed an observational and longitudinal design. Women with natural menstrual cycles and users of combined oral contraceptives were assessed at different time points. The final functional connectivity analyses included 37 participants: 21 naturally cycling women and 16 combined oral contraceptive users.

During five minutes of eyes-open resting state, electrical brain activity was recorded using a LiveAmp 64, with active actiCap electrodes and electrode localization supported by BrainVision CapTrack, technologies developed by Brain Products. The study employed 64 active Ag/AgCl electrodes and subsequently analyzed functional connectivity in the theta and alpha frequency bands.

It is particularly noteworthy to see mobile EEG technologies from Brain Products being used to address a scientific question at the intersection of neuroscience, physiology, and sports.

The researchers examined different properties of brain networks, including global integration, local segregation, and phase synchronization.

The first result deserves attention:

when menstrual cycle phases and groups were compared alone, no significant global differences in functional connectivity were found.

This is important because it argues against an overly simplistic biological interpretation in which different phases of the menstrual cycle would necessarily produce clearly distinct brain configurations.

But the picture changed when another variable entered the analysis:

menstrual pain intensity.

When pain was included as a covariate, significant interactions emerged involving measures of network integration and segregation, particularly within the theta frequency range, as well as interactions between group and pain in measures of phase synchronization.

This is precisely where the work by Pohle and colleagues becomes especially compelling.

Perhaps We Were Looking at the Wrong Variable

Among participants with natural menstrual cycles, approximately 90% reported menstrual pain, while 43% of combined oral contraceptive users reported pain during withdrawal bleeding. Pain intensity also varied substantially between individuals.

Therefore, simply classifying someone according to a “menstrual phase” may conceal very different bodily experiences.

Two participants may be categorized within the same phase, while one body is dealing with substantial pain and the other is not.

From an experimental perspective, this matters.

Pain is no longer merely a subjective report placed at the margins of the analysis. It becomes a potential component of the neurophysiological condition being investigated.

It is essential, however, to preserve the caution shown by the authors themselves: the study did not demonstrate that these connectivity differences cause poorer athletic performance, altered decision-making, or greater injury risk. None of these outcomes were directly tested. The findings are exploratory, and the researchers explicitly call for further investigation.

Yet an important possibility emerges:

the brain’s starting condition may already be different before any task begins.

Latin America Also Needs to Ask This Question

This discussion finds important parallels in recent Latin American research.

In Brazil, Raul C. R. Prado and Monica Y. Takito, from the University of São Paulo, together with Hannah Willett and Anthony Hackney, investigated 234 non-elite female athletes participating in Summer Olympic sports. More severe premenstrual symptoms were associated with changes in training routines and with a greater perceived impact on performance before and during menstruation.

This was not an EEG study. Nevertheless, it reinforces an important point raised by Pohle and colleagues: the symptoms actually experienced by the athlete need to become part of the scientific investigation, rather than relying exclusively on where she is positioned within a menstrual calendar.

In Peru, Ivanna Querevalú-Pancorbo, Luis Rojas-Cama, Fernando Soncco-Llulluy, Jair Li, and Jaime Rosales-Rimache investigated 101 high-performance Peruvian female athletes. Their 2024 study reported a high frequency of abnormal uterine bleeding and explicitly emphasized the scarcity of this type of information among Latin American athletic populations.

This regional perspective is particularly important.

Bodies do not exist outside territory, access to healthcare, nutrition, training conditions, socioeconomic circumstances, and culture.

From the Isolated Brain to the Body-Territory

Latin American neuroscience has also produced conceptual approaches that help broaden this discussion.

In 2022, Latin American neuroscientist Agustín Ibáñez, associated with the Latin American Brain Health Institute, published an important reflection in Trends in Cognitive Sciences: The mind’s golden cage and cognition in the wild.

Ibáñez argues that understanding cognition in everyday life requires moving beyond an excessively compartmentalized view of the mind. In real-world conditions, bodily, emotional, cognitive, and environmental processes unfold dynamically and in interaction with one another.

In a complementary direction, Colombian researcher Hernando Santamaría-García, together with Agustín Ibáñez and colleagues, has recently discussed allostatic interoception: the ways in which the brain and organism integrate, anticipate, and regulate internal states in response to bodily and environmental demands. This framework involves brain-body interactions across cardiac, respiratory, immune, and metabolic systems.

These studies do not specifically investigate menstrual pain in athletes.

But they help challenge the image of a brain that first receives information and only afterward begins to produce behavior.

The organism is already happening.

At BrainLatam, we use the expression Body-Territory to think about precisely this unity.

An EEG does not record an “abstract brain.”

It records the brain activity of a specific Body-Territory, at a specific moment, traversed by its physiology, experiences, and conditions.

Pohle et al. do not use this concept, and it should not be attributed to them. Yet their study offers an especially interesting example for our reflection: when a bodily condition was incorporated into the analysis, the interpretation of brain network organization also changed.

The Body Arrives Before the Decision

Perhaps this is one of the most important contributions of the initiative by Carina Pohle and colleagues.

The publication does not attempt to transform the menstrual cycle into a universal explanation for women, the brain, or athletic performance.

It does something scientifically more productive:

it identifies a variable that may have remained hidden inside an apparently sufficient classification.

Instead of asking only:

“Which phase of the menstrual cycle is this person in?”

perhaps we should also ask:

“What is the condition of this body right now?”

The change may appear small, but it can have profound implications for future research designs.

Before we investigate movement, attention, planning, decision-making, or performance, baseline brain activity is already occurring within an organism that has a physiological state, a history, and a territory.

The body arrives before the decision.

This does not mean that the body determines the decision.

It means something more interesting:

the body participates in the conditions from which a decision may eventually emerge.

Recognizing these conditions may therefore be one of the necessary steps toward understanding not only the athlete’s brain, but the Body-Territory that enters the field.

Main Reference

Pohle, C., Büchel, D., Sandbakk, S. B., Sandbakk, Ø., Pletzer, B., & Baumeister, J. (2026). Uncovering a hidden modulator for women in sports: An exploratory study of menstrual pain and brain connectivity. Women’s Health, 22. DOI: 10.1177/17455057261456871.

Complementary References

Ibáñez, A. (2022). The mind’s golden cage and cognition in the wild. Trends in Cognitive Sciences, 26(12), 1031–1034. DOI: 10.1016/j.tics.2022.07.008.

Prado, R. C. R., Willett, H. N., Takito, M. Y., & Hackney, A. C. (2022). Impact of Premenstrual Syndrome Symptoms on Sport Routines in Nonelite Athlete Participants of Summer Olympic Sports. International Journal of Sports Physiology and Performance, 18(2), 142–147. DOI: 10.1123/ijspp.2022-0218.

Querevalú-Pancorbo, I., Rojas-Cama, L. F., Soncco-Llulluy, F., Li, J., & Rosales-Rimache, J. (2024). Abnormal uterine bleeding and associated factors: a cross-sectional study in high-performance Peruvian athletes. BMJ Open Sport & Exercise Medicine, 10(2), e001820. DOI: 10.1136/bmjsem-2023-001820.

Santamaría-García, H., Migeot, J., Medel, V., Hazelton, J. L., et al. (2025). Allostatic Interoceptive Overload Across Psychiatric and Neurological Conditions. Biological Psychiatry, 97(1), 28–40. DOI: 10.1016/j.biopsych.2024.06.024.