Newswise — Rockville, Md. (January 12, 2021)—A new study explores the physiology of elite distance runners performing at two-hour marathon pace, including how much oxygen they consume while running at high speeds. The first-of-its-kind study is published ahead of print in the Journal of Applied Physiology. It was chosen as an APSselect article for January.

Researchers studied a group of elite male distance runners that included the 2018 marathon world record holder, the 2019 world marathon champion and the former world half marathon record holder. The athletes participated in two conditions: incremental treadmill running at a range of speeds and running on an outdoor track at a speed of 13.1 miles per hour (mph)—comparable to completing a marathon in two hours. The research team measured the men’s heart rate, oxygen consumption and blood lactate levels to determine the oxygen cost of running (efficiency of using oxygen during exercise). Accumulation of lactate (lactic acid)—which the body produces as it turns food into energy during exercise—in the muscles is related to fatigue. The researchers also measured the athletes’ running force, stride length and body composition.

This is the first time scientists have directly measured the oxygen cost of running outdoors at a two-hour marathon pace. Only seven of the 16 athlete volunteers were able to achieve a VO2 steady state—when oxygen consumption remains stable—when running at the two-hour marathon pace, which underscores the extreme difficulty of completing the event in under two hours. However, even with these challenges, the volunteer group was able to sustain a VO2 of 67 milliliters per kilogram of body weight per minute (ml/kg/min) at 13.1 mph, approximately twice as much as the average person can achieve when exercising maximally. In addition, their lactate threshold—the speed at which lactate builds up in the body—occurred at a very high fraction of their VO2 max.

“These top athletes have the perfect combination of physiological characteristics for the marathon: they have a very high VO2 max; they are very economical (efficient) when running at submaximal speeds; and they can run at a high fraction of their VO2 max without accumulating lactate in their blood (making them very resistant to fatigue),” explained corresponding author Andrew M. Jones, PhD, of the University of Exeter in the U.K.

More research of “strategies which enable a higher mean oxidative metabolic rate to be sustained and/or enhance running economy will play a significant role in future improvements in marathon performance,” the research team wrote.

Read the full article, “Physiological demands of running at 2-hour marathon race pace,” published ahead of print in the Journal of Applied Physiology. It is highlighted as one of this month’s “best of the best” as part of the American Physiological Society’s APSselect program. Read all of this month’s selected research articles.

Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.