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Cranberries Offer Runners an All-Natural Boost

Competitive athletes are always looking for an extra edge that can help them improve performance. According to a new study by Concordia researchers published in the journal Physical Activity and Nutrition, athletes can find that extra edge in the common cranberry.

In a series of trials involving trained distance runners, the researchers found that ingesting a cranberry supplement for 28 consecutive days led to noticeable improvements in performance and muscle fatigue following 1,500-meter time trials. Reoxygenation rates were faster and running speeds improved by 1.5%.

"When it comes to elite athletes, any advantage can make the difference between finishing fifth or on the podium," says Andreas Bergdahl, PhD, an associate professor in the department of health, kinesiology, and applied physiology and the study's senior author.

Effects of Different Energy Systems
The researchers recruited 14 high-level runners from Concordia's varsity track and field team and from two Montreal running clubs, who are performing at least five hours of endurance training per week.

The athletes ran two time trials over three separate visits, one a 1,500 meter, the other a 400 meter. The first visit was used as a baseline. At the second, they were given a single large dose of cranberry extract two hours before running. The athletes were then instructed to consume a small dose of cranberry extract daily for 28 days, after which they repeated the runs for a third time.

"We selected these distances to test the effects the cranberry extract had on different energy systems," says Francis Parenteau, a PhD candidate and the lead study author. "The 400 meter is shorter and of higher intensity and involves the anaerobic system. The 1,500 meter uses the aerobic system but is shorter than what the athletes usually run. Since they don’t train to run that distance, we were able to isolate training effects as a variable."

Besides their running time, the researchers measured their postexercise blood lactate, a marker for potential muscle fatigue and lack of oxygen. They also attached a portable near-infrared spectroscopy device to the runners to measure muscle oxygenation levels before, during, and after their runs.

Following data analysis, the researchers found that 28 days of cranberry extract consumption demonstrated a trend toward increased speed in the 1,500-meter time trial but not in the 400 meter. However, they did notice reduced lactate buildup following the 400 meter but not the 1,500 meter compared with baseline.

The data also showed that the cranberry extract promoted better oxygen extraction by the muscle, improved lactate clearance, and slower muscle deoxygenation.

Runner's Best Friend
Cranberries are extraordinarily rich in polyphenols, a natural compound with antioxidant properties. These characteristics help protect the body from the harmful effects of free radical molecules produced by strenuous exercise.

Cranberries also are indigenous to and a major industrial crop for Quebec. The province produces roughly 60% of Canada's cranberry yield, according to Statistics Canada.

"The beauty of this is that it’s all natural," Bergdahl says. "It’s an ergogenic aid, meaning that it’s performance enhancing, but it’s not an anabolic steroid. Athletes can get this important boost in their performance just by consuming more cranberries."

— Source: Concordia University