At the 1924 Boston Marathon, several doctors observed that many runners reached the finish line with clear symptoms of hypoglycemia. A year later, they tested an intervention that was as simple as it was innovative for the time: providing glucose before and during the race. That idea helped lay one of the foundations of modern sports nutrition.
Boston, 1924
The atmosphere at the finish line of the Boston Marathon was very different from today. There were no energy gels, no isotonic drinks, and no carefully calculated nutritional strategies. Runners simply ran. And they reached their limits.
That year, however, something particularly caught the attention of several doctors and researchers observing the athletes as they finished. Many runners did not just cross the finish line exhausted: some arrived pale, trembling, and disoriented. Others could not even finish the race and collapsed before reaching it.
A question at the finish line
Those scenes raised a question that was as simple as it was important:
What was happening inside the bodies of those runners after 42 kilometers?
To answer it, the researchers did something unusual for a race at the time: they waited for the runners at the finish line to take blood samples immediately after they completed the race.
Their aim was to analyze how certain chemical components of the blood changed after extreme exertion, with particular attention to glucose.
The key finding: hypoglycemia
What they found was clear. The runners who arrived in the worst condition —the most exhausted, the palest, those who could barely remain standing— had extraordinarily low blood glucose levels. In some cases, even below 45 mg/dl.
Put simply: they had used up almost all of their available fuel.
That finding helped shape a decisive idea. If the problem was the drop in glucose during prolonged exertion, perhaps it could be prevented by providing sugar before or during the race.
1925: the sugar experiment
The following year, in 1925, they decided to test that hypothesis.
They introduced a nutritional strategy that, viewed from today, seems elementary, but was novel at the time: increasing carbohydrate availability before the race and administering sugar during the marathon.
No gels.
No sports drinks.
No sophisticated formulas.
Just glucose in its simplest form: candies administered at specific points during the race.
From sugar to nutritional strategy
The results reinforced the same idea: when runners received glucose, the drop in blood sugar could be reduced and signs of extreme exhaustion were less severe.
This was not yet sports nutrition as we understand it today, but it did point to a fundamental principle: the ability to sustain prolonged exertion depends, to a great extent, on fuel availability.
In other words, the problem was not just fatigue. It was also running out of usable energy.
The origin of an idea that seems obvious today
Today, no one is surprised to hear about carbohydrates before or during an endurance event. The Endurance range from Life Pro includes products for this type of exertion, from gels such as Ultra Gel to formats such as Gumbar or isotonic preparations such as Hydra Pro. But more than a century ago, that idea began in a much simpler way.
Not with sophisticated products.
Not with marketing.
Not with complex protocols.
But with a clinical observation, a well-formed scientific question, and a surprisingly simple solution: providing the body with sugar before it ran out of it.
A lesson that remains relevant
Modern sports nutrition was not born all at once or fully formed. It began to take shape when someone decided to look closely at what was happening to those runners at the finish line.
And what they found in their blood helped establish an idea that remains fundamental in every endurance sport today:
you cannot run 42 kilometers without fuel.
Bibliographical references
Levine, S. A., Gordon, B., & Derick, C. L. (1924). Some changes in the chemical constituents of the blood following a marathon race: with special reference to the development of hypoglycemia. Journal of the American Medical Association, 82(22), 1778-1779.
Gordon, B., Kohn, L. A., Levine, S. A., Matton, M., Scriver, W. D. M., & Whiting, W. B. (1925). Sugar content of the blood in runners following a marathon race: With especial reference to the prevention of hypoglycemia: Further observations. Journal of the American Medical Association, 85(7), 508-509.