A group of ultramarathon runners race each other.
Ultramarathon runners’ recovered from pain and fatigue within five days but, they didn’t regain their normal running speed within that time. (For Spectrum Health Beat)

It takes ultramarathon runners about five days to recover from an event, a new study shows.

Ultramarathons are much longer and more physically demanding than the traditional 26.2-mile marathon. These races have become increasingly popular, according to the researchers.

Despite high levels of physical stress on the body, some runners compete in multiple ultramarathons a year. This makes it important to learn more about the recovery process, the researchers added.

They studied 72 people who took part in the 2015 Western States Endurance Run, a 100-mile race through the Sierra Nevada mountains of northern California. Runners climb approximately 18,000 feet during this race, the researchers said.

Typically, runners need 24 to 72 hours to recover from exercise-linked muscle pain and soreness, the researchers said. But, the runners in this study needed an average of five days to recover, the researchers noted. However, they said a longer recovery time is to be expected from such a physically demanding event.

But while the runners’ recovered from pain and fatigue within an average of five days, they didn’t regain their normal running speed within that time, the study found.

The researchers also found that older runners had slightly less muscle pain and soreness than younger runners. In addition, higher concentrations of a substance called plasma creatine kinase after the race were associated with more muscle pain and soreness.

The study was presented recently at the Association of Academic Physiatrists’ annual meeting in Sacramento, Calif. Findings presented at meetings are generally viewed as preliminary until they’ve been published in a peer-reviewed journal.

“This study sheds light on the factors that impact a person’s physical and functional recovery from running an ultramarathon. As athletes continue to push the boundaries of strength and endurance, it becomes more important to study the effects of these activities as well as measures that could aid in recovery,” Joseph Chin, who was with the VA Northern California Healthcare System at the time of the study, said in an association news release.