Good to the Last Drop

Caffeine has a potential role in marathon deaths by heart attack, Jen A. Miller writes. Runners need to know how to self-medicate this drug.

Caffeine: the drug

Caffeine is the most commonly used psychoactive drug in the world. Yes, it is a drug, and it can be addictive. Caffeine stimulates the central nervous system and increases heart rate. It also boosts dopamine levels in the same way as heroin, but at a much lower level.

Caffeine-delivery systems

Starting three years ago, the International Marathon Medical Directors Association (IMMDA) has warned runners to ingest no more than 200 mg of caffeine before and during a race, based on research that has shown that during exercise, caffeine affects the heart in ways that can send someone into cardiac arrest. “Every incident is disturbing,” says Dr. Lewis G. Maharam, chairman of the board of governors for the IMMDA and medical director of the Leukemia Lymphoma Society’s Team in Training. There was no single incident that led the group to put out the warning in 2010, but it stemmed from a “constant conversation on how to be safer.”

The finish-line heart attack death

Despite the benefits of running, marathoning can inflame heart tissue, even in healthy runners who have run multiple marathons or half marathons without incident. It can also trigger underlying heart disease in middle-aged runners, even if these runners previously had unexceptional heart exams and stress tests.

The business of caffeinating runners

Most runners need to eat during a race to replenish the water, electrolytes, and minerals (like sodium and potassium) that they’re sweating out and to feed themselves carbohydrates to have fuel to burn, especially if they’re running four to six hours.

A survey of consumption

I conducted an informal Internet-based survey using Google Forms through The Magazine, and 213 runners responded. This was absolutely a self-selected group, and we told them we would be asking questions about their caffeine consumption. I wasn’t attempting to get a statistically valid sample. Rather, I wanted to know how a sufficient number of runners motivated enough to respond interacted with caffeine in racing. (We promised anonymity, but noted we would quote aggregate data and responses in this article.)

Join the discussion on Twitter and Facebook with #lastdrop

Of respondents, 70 percent said they ingest caffeinated items during a marathon. Seventy-three percent of those runners said they did not look up a manufacturer’s recommended dosage before trying them, and 68 percent said that they weren’t concerned about caffeine’s effects on them during a race.

Connecting caffeine to heart attack deaths

So why hasn’t this link been made clear? Why aren’t all races following the IMMDA guidelines?

Just say no

“Caffeine! Caffeine!”

Bibliography and sources

For more academic reading on the subject, these are the principal research papers upon which I relied in preparing this article.

Caffeine, the drug

“Caffeine Induces Dopamine and Glutamate Release in the Shell of the Nucleus Accumbens,” The Journal of Neuroscience, August 2002 (download as PDF)

Perks of caffeine, non-exercise studies

“Caffeine prevents age-associated recognition memory decline and changes brain-derived neurotrophic factor and tirosine kinase receptor (TrkB) content in mice,” Neuroscience, June 2008 (download as PDF)

Perks of caffeine, exercise studies

Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review,” Journal of Strength and Conditioning, January 2010

Caffeine and the heart in exercise

“Cardiac Arrest during Long-Distance Running Races,” New England Journal of Medicine, January 2012 download as PDF

Issue 31 of The Magazine



Narrative non-fiction writing from a fortnightly periodical for curious people with a technical bent.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
The Magazine

A fortnightly periodical of features for curious people. Get The Magazine app for iPad, iPhone, & iPod touch in the iOS App Store, or subscribe on the Web.