In 2011, Fauja Singh became the oldest person to run a marathon when he completed all 42 kilometers of a Toronto race in just over 8 hours. Singh—100 at the time (and still active today)—is exceptional, but he’s not alone. People train and compete in athletic events well into their 70s, 80s, and 90s.
Now, scientists have some new clues to how they do it. The cells of these individuals produce different levels of more than 800 types of proteins than those of sedentary seniors, muscle biopsies reveal. Many of these proteins are involved with the mitochondria, which power the cell.
Scientists had already noticed some effects of physical activity on mitocondria. People who exercise about 30 minutes per day, for example, pump out more proteins that help power mitochondria than do sedentary people.
To figure out what these proteins were doing in active seniors, Russell Hepple, a muscle biologist at the University of Florida, did some unusual field research. Hepple has a senior athlete in his own life: His wife’s father holds the record for fastest finish for an 80-year-old at the Boston Marathon. So at his father-in-law’s track meets, Hepple and his family handed out fliers to racers as they came across the finish line, hoping to recruit them for a study.
He and his colleagues also reached out to senior world-record holders, eventually recruiting 15 senior athletes, all about 80 years old. Half competed in sprint events, half competed in endurance races, and several were best in the world for their event and age categories.
The researchers gave the volunteers an MRI and a battery of clinical tests to measure their balance, walking speed, and oxygen use. They also took a small biopsy of each participant’s vastus lateralis muscle, which stretches down the outside of the thigh. They did the same with 14 nonathlete octogenarians for comparison.
Next, the researchers used a technique called liquid chromatography to pull out proteins from the muscle samples, and another method called mass spectrometry to identify them. They found about 800 proteins that were produced in different amounts in the athletes from in the nonathletes. Nearly half were related to the mitochondria, involved with functions such as cellular respiration and boosting the number of mitochondria in cells.
Many of these proteins were produced at higher levels, but some were actually reduced. The athlete’s muscle cells made fewer proteins involved with a cellular structure called the spliceosome, for example, which helps buffer a typical cell from some effects of aging. It’s more proof that their cells aren’t aging like the rest of ours, says Luigi Ferrucci, a geriatrician at the National Institutes of Health’s National Institute on Aging and an author of the study.
Most of the proteins the team identified overlapped with those known to be boosted in athletes of any age. But 176 of the mitochondrial proteins were unique to the octogenarian athletes and could be the reason for their late-in-life athleticism, the team reports this month in eLife. They likely have a lucky combination of genes supplemented by their intense training.
“This study does a really good job showing how these athletes maintain mitochondrial health even as they get older,” says Mark Tarnopolsky, a muscle biologist at McMaster University who wasn’t involved with the research.
Now that the scientists have this list of proteins, they can start to look closely at their functions one by one by studying them in animal models, Ferrucci says. The hope is to someday develop therapeutic treatments to combat muscle decline using the resulting knowledge, he says.
“There’s no true fountain of youth,” Hepple says, “but these [senior] athletes are as close to it as you can get.”