Marathon training linked to healthier hearts

Researchers have linked marathon training with improved risk factors related to cardiovascular disease among middle-aged recreational male runners, suggesting that race preparation may be an effective strategy for reducing heart disease risk.

Researchers studied 45 recreational male runners, age 35 to 65, who were planning to run the 2013 Boston Marathon. Participants were recruited from the Dana-Farber Marathon Challenge fundraising team and were not time-qualified for the Boston Marathon.

Approximately half of the participants had run three or more marathons in their lifetime, while the other half had run two or less. They were invited to participate in the 18-week training program, which included group runs, endurance training, a detailed training guide, access to cross-training facilities in the Boston area, nutrition tips, advice about pacing, preparation hints and regular coaching correspondence.

Participants were instructed to run 12 to 36 miles each week, depending on the phase of training. Researchers tracked adherence to the training program using running logs provided by the participants.

In the study led by Jodi L. Zilinski, M.D., at Massachusetts General Hospital, and lead investigator of the study, prior to beginning the training program, participants underwent a full medical evaluation that included cardiopulmonary exercise stress testing, heart imaging studies and cholesterol screening. Just over half of study participants (24 of 45) had at least one cardiovascular risk factor including high cholesterol, high blood pressure or a family history of heart disease. Participants were re-evaluated at the end of the training program prior to running the marathon.

Participation in the 18-week program led to significant overall changes in key determinants of cardiovascular risk. Low-density lipoprotein, or LDL, known as "bad" cholesterol, was reduced by 5 percent; total cholesterol fell 4 percent, and triglycerides dropped 15 percent. There was also a 1 percent decrease in body mass index, and a 4 percent increase in peak oxygen consumption, a measurement of cardiorespiratory fitness, which is a potent prognostic marker of cardiovascular mortality.