Residents study runners for
answers on athletics

On Patriot’s Day, as 120 members of the Kids at Heart Marathon Team pounded 26 miles of pavement to raise more than $530,000 for Children’s, a second team was hard at work near the finish line. More than 40 Children’s medical residents scrambled to take blood from over 500 runners, process the samples and store them in a makeshift lab at the John Hancock Building.

The residents, led by Christopher Almond, MD, MPH, Elizabeth Fortescue, MD, Andrew Shin, MD, and Rebekah Mannix, MD, were gathering data for the Children’s Hospital Marathon Physiology Study, an ambitious project aimed at developing a new understanding of physical changes caused by endurance training and competition.

Says David Greenes, MD, associate program director of Pediatric Residency: “A core group of residents and I are the lead investigators behind this study, with an even larger group of residents that supported us on race weekend. I’ve been involved as the faculty member of the team, but the residents have done a spectacular job. Most studies are not constructed this way.”

The residents developed the study in collaboration with Children’s experts in cardiology, emergency medicine, endocrinology and women’s health. It focuses on three specific areas: heart health and risk of heart attacks or other heart-related problems; electrolyte levels in marathon running and how hydration and electrolyte disturbances can lead to health problems; and women’s health issues and marathon running, including body composition, rates of infertility and bone density levels. “These are important public health issues that have not been well studied despite the tremendous numbers of women in endurance athletics,” says Almond.

By virtue of its size, the Boston Marathon provides an ideal opportunity to gather clinical and exercise history information from runners, as well as measure levels of important blood components. “We expect to see approximately 10 percent of runners to show heart injury markers,” says Almond. The markers, known as troponins, are commonly seen as evidence of a heart attack. The researchers hope to explain the presence of these markers in healthy runners.

Studying fertility and bone loss among women is a broader question. “Infertility and bone loss in elite women athletes is essentially an unstudied area,” says Almond.

One aspect of the research will look at incidence of hyponatremia, or depleted blood sodium levels caused by overhydration without adequate electrolyte replacement. Hyponatremia can lead to mild sickness or even death, and is thought to be the leading cause of collapse in marathons. Because mild cases of hyponatremia share the symptoms of dehydration and exhaustion, there are many unanswered questions about the condition and its prevalence in endurance athletes.

The scope of the study sets it apart from past research. The residents offered free cookies and T-shirts at the pre-race expo, luring over 700 runners to participate.

Those runners filled out a pre-race questionnaire and over 500 of the participants reported back to the researchers near the finish line to give samples of their blood. Shin, a lead investigator who also ran in the event, says the researchers weren’t sure how many exhausted runners would actually return to give blood samples. “In the first hour after runners started finishing, no one came to give samples, and we started getting nervous” he says. “But eventually they started pouring in, and we really had our hands full.”

Almond says if the study’s findings prove significant, they will be reported in a peer-reviewed journal. —CM

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