If You’ve Run a Half or Full Marathon, You May Be Familiar with ‘Hitting the Wall’

In the final stretch of a marathon, the atmosphere is electric. The cheers of the crowd echo off the pavement as runners push themselves toward the finish line. Yet, for many, this moment is marred by an all-too-familiar and dreaded phenomenon: hitting the wall. A recent study conducted by Liverpool John Moores University and Science in Sport aims to unravel the complexities of marathon nutrition, providing athletes new insights to stave off fatigue and improve performance.

The Research Framework

Leading this groundbreaking exploration is Professor James Morton, Chief Science Officer at Science in Sport. His team focused on an elite group of male marathon runners, each boasting a personal best of 2 hours and 30 minutes or faster. “We brought them into the lab after carbohydrate loading the day before, along with a high carbohydrate breakfast,” Morton explains. “What sets our research apart is that we mimicked race conditions, using athletes who can sustain an intensity closest to race pace.”

Methodology

The study included eight elite male runners with an average personal best time of 2:22. These subjects completed treadmill runs at marathon pace, simultaneously consuming various carbohydrate amounts: 60, 90, or 120 grams per hour.

• 60 grams/hour: Single source, maltodextrin.
• 90 grams/hour: Dual source blend, with 60 grams of maltodextrin and 30 grams of fructose.
• 120 grams/hour: Dual source blend of 60 grams maltodextrin and 60 grams fructose.

Morton emphasizes the significance of these methods, stating, “Runners typically don’t fuel themselves adequately during marathons. We aimed to examine the effects of different carbohydrate dosages on substrate metabolism.” However, he acknowledged a known concern: gastrointestinal distress. “What we wanted to explore was the tolerability of these varying carbohydrate levels.”

The Findings

The results were telling. Researchers discovered that carbohydrate oxidation increased in a dose-dependent manner. At the 120 grams intake, runners not only burned a greater quantity of carbs but also displayed a 2.6% decrease in oxygen consumption—a compelling indicator of improved running economy. “In the high carbohydrate trial, athletes could oxidize 1.5-1.7 grams of carbohydrates per minute,” Morton notes, “a remarkable achievement.”

This elevated carbohydrate usage suggests that runners can and should consume more energy efficiently during long races. Still, even at the highest intake level, there was a decline in overall carbohydrate use during the last 30 minutes of exercise, reiterating the essential need for fueling strategies even among elite athletes.

Revising Carbohydrate Guidelines

Traditionally, the recommendations for carbohydrate intake have ranged from 30 to 90 grams per hour based on the duration and intensity of exercise, according to guidelines last published in 2016. Morton states, “If your event is 60 minutes or less, you’re looking at about 30 grams per hour. For events lasting 2.5 hours or more, you should be aiming for at least 90 grams per hour.” But what about those looking to push the limits?

What This Means for Athletes

As Morton synthesizes the findings, he asserts, “If you really want to go fast, you should consider consuming between 90 and 120 grams of carbohydrates per hour.” This revised insight could revolutionize how runners approach their nutritional strategy. “For runners, it’s essential to practice this fuelling strategy consistently. If they do, they’ll be able to metabolize and utilize this carbohydrate effectively come race day.”

Incorporating such a significant carbohydrate load may appear daunting, particularly juxtaposed against traditional advice. However, Morton emphasizes that athletes who engage in strategic training and experimentation with their fuelling will experience significant performance boosts. “This work will change not only the recommendations given to elite runners but also how they prepare for endurance events,” he says.

Practical Implications

From the data, key takeaways for runners include:

• Carbohydrate loading the day before a race significantly improves performance.
• A carbohydrate-rich breakfast should be part of pre-race nutrition.
• Experimenting with 90-120 grams of carbohydrates during the race can yield optimal results.

This evolving landscape of sports nutrition marries science with dedication, offering a path forward for athletes seeking to shatter their personal barriers. As Morton puts it simply, “Practice makes perfect. If runners commit to these strategies, they can achieve substantially faster times.”

In a world where human potential is continually redefined, this research sheds light not only on the science of endurance running but also on the driven athletes who relentlessly chase their goals, one step at a time.

Source: www.menshealth.com