The Illusion of Certainty: Taleb, Popper, and the Medical Certificate (Apto Médico) in Running in Buenos Aires

Walk through Palermo and Recoleta, CABA

Urban hiking (Urban Trek), city-trekking, and low-intensity steady-state urban walking (LISS). An active yet contemplative route.
Walking through some streets in the neighborhoods of Palermo and Recoleta.
Urban walk: starting and finishing at Plaza Italia. Crossing Av. Coronel Díaz brings you into Recoleta. Outbound along Arenales to Av. Pueyrredón, and returning via Av. Las Heras.

Medical Certificate (Apto físico or apto médico)

This walk was done to renew the medical certificate required to participate in races.
The medical certificate is required for all races of 5 km and above. Larger platforms usually allow uploading it online. Mid-sized organizations are often satisfied with just a signed waiver, while some smaller organizers—more responsible, cautious, or fearful—require bringing a physical hard copy (a photocopy). Those that request it online check whether it is up to date when delivering the race kit.

The medical certificate generally lasts for 1 year. Costs for those getting it privately range from 25,000 to 45,000 pesos as of today (approximately 16 to 29 USD). These are "standard" medical certificates. There are other, more comprehensive ones (which include clinical lab work, among other tests) that cost more, but these are specific to certain high-performance competitions or athletes. For "regular" road races, basic medical clearances are sufficient.
An entire industry dedicated to this exists, complete with exclusive social media advertising, word-of-mouth communication, organizer recommendations, and suggestions from training groups. And, of course, it can also be covered by health insurance plans and prepaid medical care (obras sociales and prepagas).

The examination generally consists of a resting electrocardiogram (ECG) + stress test (ergometry) + Doppler echocardiogram.

On this occasion, I arrived at the health center and had a stress ergometry (which includes an exercise electrocardiogram) + Doppler echocardiogram performed. Everything came back fine, enabling me to run for another year.

For my part, I activated my basic, entry-level smartwatch that measures heart rate. I kept it active the entire time, including during the bicycle stress test. Recording the entire duration of the exercise with the corresponding minutes, resistance, and speed, it registered a peak heart rate of 163 bpm. However, during races I have reached peak heart rates of 172 and 174, and in certain training sessions I have reached 178.

I brought this minor observation to an AI for analysis and explanation:

The difference observed between the peak heart rate (HRmax) during the test and during races or hard training sessions is a very common phenomenon with very specific physiological and methodological explanations:

1.    Stationary Bike Ergometry vs. Running

o    Muscular mass involved: The stationary bike (cycle ergometer) primarily uses the quadriceps. By recruiting less total muscle mass than running (which engages full legs, arm swing, core, and stabilization), oxygen demand and peak cardiac response are typically 5% to 10% lower on a bike than while running.

o    Prior localized fatigue: On the bike, the legs often "fill with lactate" and fatigue before the cardiovascular system reaches its actual operational limit.

2.    Emotional and Environmental Factors (The "Bib Effect")

o    Race adrenaline: Motivation, the presence of other runners, and the tension of race pacing release catecholamines (adrenaline and noradrenaline), allowing the heart to beat at higher frequencies than in the controlled, cool, and neutral setting of a doctor's office.

o    Thermoregulation and dehydration: During outdoor races or training, body heat increases, the body loses fluids, and cardiovascular drift occurs: the heart must beat faster to maintain the same stroke volume per minute.

3.    Technological Accuracy (Smartwatch vs. Electrocardiograph)

o    Optical sensor (PPG) vs. Electrodes (ECG): The entry-level watch measures pulse using light sensors on the wrist, making it susceptible to interference from movement, sweat, or slight fit adjustments. Ergometry measures direct electrical activity of the heart via chest electrodes.

o    Cadence and bounce: When running on foot, arm swing can produce a phenomenon called cadence lock (where the watch mistakes stride cadence for heart rate), something that does not happen while holding stationary bike handlebars.

What the Result Means

Reaching 163 bpm during the ergometry without arrhythmias, ischemia, or blood pressure anomalies demonstrates that your heart responds safely under load. Reaching 172–178 bpm on the street simply reflects your actual functional reserve when running, facilitated by movement-specific mechanics, race enthusiasm, and maximum exertion on the road.

The Critique: Is the Medical Certificate Actually Useful?

That figure of 163 in the doctor's office versus 178 on the street is precisely what leads me to pose a critique, attempting to approach it from a skeptical, empiricist viewpoint grounded in the following questions: Methodological application? Is it truly useful or not? Actual probabilities and evidence? Prior statistics or absence of statistics? Along with relevant philosophical and analytical perspectives.

The argument touches on a key point: the gap between bureaucratic medical protocol and the complexity of real human physiology. Requiring a medical certificate is an excellent and necessary preventive measure, but when examined under an epistemic lens, it reveals several inconsistencies and illusions of security.

Is the Basic Certificate Useful? Statistics and the Prevention Paradox

The primary goal of requiring a medical certificate in popular races is to prevent Sudden Cardiac Death (SCD).

•    Actual incidence: Sudden death in marathons and road races is statistically rare, occurring in roughly 0.5 to 1 per 100,000 runners.

•    Screening efficacy: A resting electrocardiogram (ECG) combined with a stress test detects severe structural pathologies (such as hypertrophic cardiomyopathy or advanced ischemic heart disease) in symptomatic or high-risk individuals. However, in asymptomatic athletes, the sensitivity of these tests to predict a future lethal event is relatively low.

•    False positives and false negatives:

o    False negative: A "normal" bicycle ergometry does not guarantee 100% that an atheromatous plaque will not rupture under thermal stress, dehydration, and extreme adrenaline surge at kilometer 18 of a race.

o    False positive: Generates unnecessary anxiety, additional costs, and medical over-testing in healthy athletes.

Something worth mentioning: theoretical formulas (220−age) have a deviation of ±12 bpm, so no single number represents "the" true HRmax. This discussion is highly complex and leans heavily into technical and specific medical territory.

Where the Numbers Hold (and Where to Adjust Them)

The cited incidence (0.5–1 per 100,000) matches published literature: the RACER registry, tracking ~30 million marathon and half-marathon finishers in the US (2010–2023), reported 0.60 cardiac arrests per 100,000 runners (1.12 in men vs. 0.19 in women). The classic Marine Corps/Twin Cities study had already shown ~1 in 50,000 and explicitly concluded that routine screening "may not be justifiable."

A key nuance: In competitive young athletes, the risk is not negligible—up to 5.6 per 100,000 according to MacLachlan et al.—and the causal profile shifts (cardiomyopathies, myocarditis) compared to master runners, where coronary artery disease dominates (Frontiers). It is worth distinguishing between both groups within the critique.

The Argentine Case

What exists in Argentina: There is no national registry or systematic statistics. Local medical media explicitly admits this: "In Argentina, where there are no data in this regard, individual cases are always news" (El Día). In other words, we rely on anecdotes rather than calculated incidence. There is no Argentine equivalent to the US RACER registry (which tracked ~30 million runners over decades).

Known cases (the dark chronicle of Buenos Aires running):

•    2018 Buenos Aires Half Marathon: A 55-year-old runner from Santa Fe collapsed 300 meters before the finish line and died five days later. Key detail for this critique: he had undergone complete medical testing (ECG, maximum-intensity ergometry, Doppler echocardiogram, carotid artery ultrasound, blood work) and still died. Family physicians pointed out that even carotid ultrasound carries a recommendation against use in asymptomatic individuals due to over-diagnosis (AMMF / La Nación).

•    2022 Buenos Aires 21K: A 30-year-old Chilean woman suffered sudden death upon crossing the finish line—resuscitated after 22 minutes without a pulse, she survived (La Nación).

•    2024 Mar del Plata: A runner passed away during the marathon among more than 4,000 participants (El Día).

•    2026 Buenos Aires 21K: One death among ~31,160 registered participants (La Nación).

Contextual figures used by Argentine cardiology: When local media cite numbers, they draw from international data: an incidence of ~1.6 per 100,000 in marathons, and the Japanese study (251 races, 1,965,265 runners, 1.56 arrests per 100,000, 93% successful resuscitation with bicycle-borne AEDs) (Clarín). Note: The 0.5–1/100,000 figure applies to the US; the Japanese figure is higher (~1.6), likely due to a different participant demographic.

Nassim Taleb's Critique: Illusion of Control and Iatrogenesis

Nassim Nicholas Taleb (author of The Black Swan and Antifragile) proposes several concepts applicable to this scenario:

•    The Illusion of Certainty (Black Swans): Signing a document or stamping a medical certificate creates a false sense of security. The bureaucratic system assumes that risk is reduced to zero because the test came back normal. In reality, sudden death is typically a "Black Swan" event: rare, high-impact, and

unpredictable through standardized 15-minute protocols in a sterile environment.
•    Medical Interventionism and Iatrogenesis: Taleb criticizes the tendency to apply complex screenings to young, asymptomatic populations. The risk of over-medicating or diagnosing clinically irrelevant "incidental findings" (iatrogenesis) sometimes outweighs the statistical benefit of the test.

•    Naive Empiricism: Evaluating the heart at 163 bpm on an exercise bike in an air-conditioned room without competitive stress, in order to clear someone to run at 178 bpm under scorching heat, extrapolates data from an unrepresentative environment to a complex system far out of equilibrium.

Karl Popper's Critique: Falsifiability and the Illusion of "History"

Karl Popper argued that for a statement to be scientific, it must be falsifiable; furthermore, he criticized "historicism"—the idea that we can predict the future solely by looking at past records.

•    The study measures the past, not the future: An ECG and ergometry tell the physician how your heart performed over the preceding 15 minutes. Extrapolating that it will remain healthy over the next 365 days under any physical condition is an inductive fallacy (the same one illustrated by Russell's "Turkey Illusion" adapted to sports medicine, a metaphor Taleb frequently recycles).

•    Absence of a stress test to failure: In the clinic, ergometry is stopped upon reaching a theoretical target percentage or due to local muscle fatigue (lactate-heavy quadriceps). By not pushing the system to its actual breaking point or maximum effort (as occurs during a final race sprint), the hypothesis that "your heart tolerates maximum effort" was never actually refuted or tested (falsified) in the lab.

•    Unfalsifiability due to statistical opacity: The absence of Argentine statistics is not a neutral vacuum; it is the condition that enables the medical certificate to function as an un accountable ritual. If no one tracks how many certificate holders suffer cardiac arrests in Argentina, the hypothesis that "the certificate prevents SCD" remains unfalsifiable at the local level—it can neither be confirmed nor refuted. The system demands the paper, but never audits whether the paper works. Cases from 2018 and 2026 (complete exams + death) show that even "ideal" screening guarantees nothing, whereas survivors (2018, 2022) were saved by AEDs and CPR on the course, not by prior prevention. By failing to audit or measure the correlation between submitted certificates and adverse events on the street, the administrative requirement becomes a bureaucratic ritual immune to refutation—an act of normative faith rather than epidemiological rigor.

Nuances to the Taleb/Popper Perspective

Taleb would also argue the inverse: in Antifragile, he praises the stressor of running as something that strengthens the system. His critique would target low-signal bureaucratic screening, not exercise itself. This perspective can be used to support urban walking.

The Popperian argument also faces an empirical counter-example: records show that survival from cardiac arrest during races improved with on-course defibrillators—meaning the life-saving intervention is not the clearance certificate, but rapid in situ response. This reinforces the core point: funds allocated to mass screening might yield greater returns if invested in emergency logistics.

Final Reflection

Raising this critique does not mean dismissing medicine or opposing health checkups. On the contrary, the coherent recommendation is to obtain comprehensive medical studies (adding blood work, Doppler echocardiography, and personalized cardiological consultations) while understanding their inherent limitations.

The administrative medical certificate functions as a low-cost, mass filter to detect obvious abnormalities, but it should never replace an athlete's self-awareness, progressive training, or prudence when the body sends signals out on the street.

 

Wikiloc Link: https://es.wikiloc.com/rutas-senderismo/walk-through-palermo-and-recoleta-caba-physical-fit-clearance-290489198

 

International Statistics

•    RACER Registry (TCTMD): https://www.tctmd.com/news/racer-no-change-cardiac-arrests-during-marathons-survival
•    Marine Corps/Twin Cities Study (PubMed): https://pubmed.ncbi.nlm.nih.gov/8800121/
•    NEJM Full Study on the same registry: https://www.nejm.org/doi/full/10.1056/NEJMoa1106468

Argentine Cases

•    2018 Buenos Aires Half Marathon (La Nación, runner who died five days later): https://www.lanacion.com.ar/sociedad/un-corredor-se-descompenso-a-300-metros-de-la-llegada-de-la-media-maraton-de-buenos-aires-y-murio-nid04092026/
•    2018 Coverage (La Nación, runner's death): https://www.lanacion.com.ar/deportes/murio-corredor-media-maraton-buenos-aires-otro-nid2165933/
•    2022 Buenos Aires 21K (Chilean woman resuscitated after 22 minutes, La Nueva / El Ciudadano): https://www.lanueva.com/nota/2022-8-24-11-42-0-corrio-los-21k-de-buenos-aires-se-descompenso-y-la-reanimaron-estuve-22-minutos-muerta
•    2024 Mar del Plata (El Día): https://www.eldia.com/nota/2024-4-15-4-37-35-conmocion-murio-un-corredor-en-la-maraton-de-mar-del-plata-informacion-general
•    2024 Mar del Plata (La Nación): https://www.lanacion.com.ar/sociedad/conmocion-por-la-muerte-de-un-atleta-porteno-de-48-anos-en-la-maraton-de-mar-del-plata-nid14042024/

Japanese Study / Contextual Figures

•    Clarín (Japanese method, 93% successful resuscitation): https://www.clarin.com/sociedad/muertes-maratones-exitoso-metodo-japones-salvo-93-infartados-carreras_0_Hy_tv1XDQ.html

Indirect Citation:

•    MacLachlan et al. (5.6/100,000 in youth): exact Frontiers article not found; data appears in this review on sudden death in athletes: https://pmc.ncbi.nlm.nih.gov/articles/PMC9965876/

 

This essay was prepared with the support of artificial intelligence tools: Gemini and Mistral.