Sports Science: A legal substance enhancing athletes and breaking records

On February 14, Grant Fisher stepped off the track at Boston University, having just shattered the world record for the indoor 5,000 meters. While an incredible feat, it wasn’t entirely unexpected. The 27-year-old American distance runner was in peak form, having set a world record in the 3,000 meters just six days prior in New York City. His achievements were aided by state-of-the-art Nike spikes and one of the fastest tracks in the world. However, when asked what contributed to his record-breaking performances, Fisher pointed to something surprisingly simple: baking soda.

“I think it makes an impact, and if that impact is 1%, that would be massive,” Fisher said. “It’s probably more like 0.1%, if there is one. And if it is just mental, then I’ll take that, too.”

Baking soda, or sodium bicarbonate—often referred to as “bicarb” in the running world—has gained popularity among elite athletes as a legal performance enhancer. Its use has grown so much that at the 2023 World Championships, two-thirds of all medalists from 800 to 10,000 meters reportedly used a bicarbonate supplement from Maurten, a Swedish company. The trend continued at the Olympics, where Maurten claimed that more than two-thirds of all running medalists—and sometimes entire fields of finalists—were using it.

In February alone, seven world records across events ranging from the 1,500 meters to the road half-marathon were broken. Advancements in technology, from faster shoes and tracks to improved recovery and coaching, have contributed to the surge in performances. Mississippi State University’s head track coach, Chris Woods, believes the trend will continue, predicting that even seemingly impossible records—such as a woman breaking the 4-minute mile—could soon be within reach.

One key reason for the rise of bicarbonate use is its role in buffering acidity in the muscles. Intense exercise leads to a buildup of hydrogen ions, which cause fatigue and the well-known burning sensation. As a base, sodium bicarbonate helps neutralize this acidity, potentially delaying fatigue and enhancing endurance. Crucially, it is legal under World Anti-Doping Agency rules and recognized by World Athletics as a legitimate performance supplement.

Despite its benefits, bicarbonate’s history is marked by one significant drawback: gastrointestinal distress. Many athletes have avoided it due to its potential to cause nausea, vomiting, or diarrhea. Steve Magness, a coach and former elite runner, noted that early attempts at using bicarbonate often ended in disaster. “A high percentage of people just couldn’t even line up for the race or time trial because it tore apart their stomach,” he explained.

Fisher, aware of these risks, waited until after the Olympic cycle to experiment with bicarbonate. Fortunately, his stomach tolerated it well. Recent innovations may explain why. Maurten has developed a hydrogel technology that encases bicarbonate in small tablets, allowing it to pass through the stomach and dissolve in the intestine, reducing side effects. However, the company warns of potential water retention, weight gain, and increased sodium intake leading to higher blood pressure.

Beyond improved formulation, new research has also reshaped views on bicarbonate’s effectiveness. While traditionally thought to benefit only short-duration events, a study from Edge Hill University in the UK found that Maurten’s bicarbonate supplement improved cyclists’ performance by 1.4% in a 40-kilometer time trial—nearly the length of a marathon. This suggests bicarbonate may be beneficial for longer endurance events as well.

With elite athletes like Eliud Kipchoge and Keely Hodgkinson endorsing Maurten’s products, it’s clear that bicarbonate supplementation is more than a passing trend. As runners continue pushing the limits of human performance, it may become an increasingly common tool in their pursuit of world records.

Reno Silva/MS