Marathons have been increasing in popularity over the last decade, with 487,000 people finishing one in 2012 alone (up from 25,000 in 1976 and 353,000 in 2000). And now, a small new study shows that middle-aged people training for a marathon could be doing their hearts a favor.
Research presented at a meeting of the American College of Cardiology shows that middle-aged non-elite runners had improved heart risk factors -- such as cholesterol and triglyceride levels and body mass index -- from training for a marathon.
"Overall, participants experienced cardiac remodeling -- improvements in the size, shape, structure and function of the heart," study researcher Dr. Jodi L. Zilinski, M.D., of Massachusetts General Hospital, said in a statement. "Even with a relatively healthy population that was not exercise naïve, our study participants still had overall improvements in key indices of heart health."
The study included 45 men who ran for recreational purposes who were between ages 35 and 65; more than half had at least one cardiovascular risk factor (such as a family history of heart disease, high blood pressure or high cholesterol). The men were all training to run the Boston Marathon in 2013; about half of the men had run at least three marathons before, while the other half ran two or fewer marathons in their life.
None of the men were time-qualified for the race, and all of them were running for charity.
"We chose charity runners because we wanted to focus on the non-elite type of runner, just the average Joe who decides to get out there and train for a marathon," Zilinski explained. "They turned out to be a healthier population than we expected with a lot of them already exercising on a pretty regular basis, but they were still nowhere near the levels of elite runners."
The researchers recruited these men to participate in an 18-week training regimen, which included endurance training, group runs, nutrition tips and access to cross-training facilities and regular coaching. Dependent on where they were in their training schedule, the men ran anywhere from 12 to 36 miles a week. At the beginning and end of the training program (but before actually running the marathon), the men all underwent medical evaluations.
Researchers found improvements across the board in the men's cardiovascular risk factors. For instance, "bad" cholesterol levels went down by 5 percent and total cholesterol levels went down by 4 percent. Peak oxygen consumption -- which is indicative of cardiorespiratory fitness -- increased 4 percent. And body mass index decreased 1 percent.
The findings support the idea that training for a big race is a great way to reduce your heart risk factors, the researchers said, though they noted that people should talk to their doctors before embarking on such a rigorous training program.
Because the findings have yet to be published in a peer-reviewed journal, they should be regarded as preliminary.