First Time Marathon Runners: Despite Light Training, They Face No Heart Risks, But Gain Blood Vessel Benefits

As first-time marathoners flooded into the sport over the last 25 years, some observers worried that their inadequate preparation might leave them with heart damage and/or other problems. Indeed, one early study showed that marathon finishers who trained under 35 miles a week had nine times more troponin leakage--a measure of heart-muscle injury--than those who trained over 45 miles a week. While the authors stated “There is no data to suggest that there are long-term sequelae,” the troponin finding looked ominous.

Now a new British report based on a group of London Marathon runners seems to lay the heart worry to rest. It shows that first-time marathoners who run roughly 25 miles a week in training enjoy a modest reduction in blood pressure and “no evidence of myocardial fibrosis [scarring] or persistent edema” after completing a first marathon in an average time of 4:31.

The research team, including London Marathon medical director Sanjay Sharma, concluded: “Despite ongoing concerns regarding the cardiovascular safety of marathon running … we found no evidence of myocardial injury in first-time marathon runners achieving an average finishing time.” A free full-text version of the paper is available here from Frontiers in Physiology. 

To investigate potential heart harms of a first marathon, the researchers gathered and tested 68 novice marathoners six months before the 2016 London Marathon and two weeks after. All subjects received an exercise performance test, as well as extensive heart measurements, including electrocardiography and a heart MRI. 

Subjects were young by design, with an average age of 30, so they were unlikely to have underlying atherosclerosis. Thirty six were men, and 32 women. All but two of the 68 runners completed the marathon.

The runners were advised to follow the London Marathon’s 16-week training program for first-time marathoners. Since a third of them wore personal digital tracking devices when running, they were able to provide objective evidence of their actual workout compliance. These training logs revealed that the runners did 78 percent of the suggested mileage. 

This amounted to about 2.5 hours a week of training (about 15 miles) at the outset, and about 4.5 hours (roughly 25 miles/week) at peak training three weeks before the London Marathon.

The male subjects finished London in an average time of 4:14:30 and the women in 4:43:40. This was slightly slower than London’s overall average finish times among runners who presumably trained more, but were also likely 5-10 years older.

The pre-marathon and post-marathon testing revealed no heart damage, as noted. It also showed that the runners’ average blood pressure had dropped by 4 points (systolic) and 2 points (diastolic). The paper noted that this is “comparable to the effects of antihypertensive medication,” and would likely reflect an 11 percent lower risk of stroke and 7 percent lower risk of heart disease in a young group with an already low risk profile. 

Somewhat surprisingly, the runners showed no increase in basic fitness post marathon training as measured by vo2 max testing. This could be, the study team speculated, because the runners were still not fully recovered from their marathon effort.

It’s likewise possible that the runners’ unsupervised training was so modest that it simply didn’t increase their cardiovascular fitness, which generally gets the biggest bang from relatively fast running. The runners also showed no change in pre- and post-marathon BMI (average, 23.5) or body fat percent (average, 22.5 percent).

The study team noted two other post-marathon changes with possible benefits to the runners: They had lower “aortic pulse wave velocity” and a lower level of blood creatinine. The first is a measure of artery flexibility vs stiffness. “The lower the aortic pulse wave velocity, the more elastic, healthy, and youthful the artery,” explained first author Andrew D’Silva, a London-based cardiologist. “The higher it gets, the stiffer the arteries, which can happen in ageing but also through disease processes like high blood pressure and diabetes.”

Creatinine is a measure of kidney strain or injury. Some previous marathon blood-test analyses, performed immediately after the finish, have revealed high levels of creatinine. This presumably results because the kidneys have to work overtime to clear the byproducts of muscle-breakdown. The new study didn’t draw blood until two weeks post-marathon, when subjects’ creatinine was lower than six months pre-marathon. 

“This drop in creatinine that we observed may mean that kidney functioning was enhanced by 17 weeks of regular running, and not impaired,” said D’Silva.

D’Silva believes the new study makes an important contribution precisely because it monitored “typical first time marathon runners” who aren’t motivated enough to follow a serious-runner training program. If anyone were likely to suffer heart damage while marathon running, it would be an under-prepared crowd. But this didn’t happen.

Instead, D’Silva observed: “The runners got beneficial improvements in the blood vessels (blood pressure, aortic pulse wave velocity) and no sign of heart damage.”

In Marathon Trials, Tierney Wolfgram, 16, Racing Cathy Schiro Record from 36 Years Ago

Schiro, 1984 Marathon Trials
As the youngest entrant in the 2020 Marathon Trials, 16-year-old Tierney Wolfgram is getting lots of attention. It’s not that anyone expects her to finish in the top 3, but youth provides its own fascination, and the average age of women in the Trials is 31. In addition, Wolfgram has her eyes set on the American high-school and junior record for the marathon

In that regard, her goal is almost impossible. She’s chasing Cathy Schiro’s performance from the inaugural U.S. women’s Olympic Marathon Trials in 1984. Schiro’s mark has stood the test of time, because it’s one of the toughest marathon marks in the U.S. record books--2:34:24.

The two have followed very similar paths. Wolfgram won the 2017 Minnesota state cross-country meet as a freshman. When Schiro was a freshman in 1981, she won the New Hampshire state meet for the second time in a row. She went on to garner three more state titles for a grand total of five.

As a 15-year-old high school sophomore, Wolfgram decided to tackle the 2018 Twin Cities Marathon. She finished sixth in 2:40:03 to notch her Trials qualifier. When she turned her attention back to cross-country, things didn’t go well. She dropped out of both her state meet and Nike Cross Nationals.

Tierney Wolfgram
Schiro ran the Kinney Nationals (which preceded Footlocker) as a frosh, soph, and junior, finishing 19th, 10th, and 3rd. In the winter of 1983/1984, her coaches, New England road veterans Tom and Marcia Dowling, presented her with a choice: to continue running track, or to give the marathon a try.

She opted for the latter, entering the Hampton, NH, Marathon in February, 1984. There, as a 16-year-old, she clocked a 2:45:16, good enough to qualify for the first Marathon Trials. (The OTQ was 2:51:16.) She skipped the spring track season to continue her marathon training, generally logging 60 to 70 miles a week with long runs that reached 22 miles. 

Wolfgram’s running was injury-plagued last year, with a metatarsal fracture in the spring and a tibia fracture in September that knocked her out of the cross-country season. By December she was healthy enough to return to serious marathon training. At that point, she moved to Albuquerque, New Mexico, for some altitude and better weather than in Minnesota. 
Schiro racing as high schooler
from Dover NH. Jeff Johnson photo

By January, she was training around 80+ miles per week. On January 19, she ran 1:16:55 in the Rock n Roll Arizona Half Marathon on a course that turned out to be 285 meters short. In a February podcast with Carrie Tollefson, she said she had gotten up to 100 miles in a week and was eyeing Schiro’s record. Her mother and father have been alternating two-week stints with her in Albuquerque.

(Another young female marathoner, Alana Hadley, ran 2:41:58 as a 16-year-old in 2013. She improved to 2:38:38 the next year to qualify for the 2016 Marathon Trials in Los Angeles. There, she dropped out, and she has since stopped racing competitively.)

Schiro says she reached the May 12, 1984 Trials in Olympia, WA, “pretty unaware of professional racing, the other runners, their times, and so on. I only knew I had trained hard, that my coaches believed in me, and I loved to run the distance.” In Olympia, the Trials organizers assigned her 54-year-old Sister Marion Irvine (who had qualified with a 2:51:00) as a roommate.

Schiro, still 16, didn’t start the marathon with a strategy. She certainly wasn’t thinking about making the Olympic team. She and her coaches decided only on a pace plan: try to hold 6:00 pace as long as possible. 

That put her in the middle of the pack early on. Then she began moving up. And just before 20 miles, something remarkable happened. Joan Benoit had a solid lead. Julie Brown was running a strong second. And Lisa Larsen (later Weidenbach and Rainsberger) held third. Only Larsen didn’t look so good.

And a little 5’1” sprite from Dover, New Hampshire, was closing in on her. For several moments, it actually looked as if Schiro might nab the third spot on the podium.

That didn’t happen. “I was too inexperienced at that point in my career,” Schiro (now O’Brien) remembers. “I had probably overextended too much. I didn’t know that you had to be careful about running aggressive even if you felt good.”

Schiro faded to ninth. Larsen finished fourth (as she would in the next two Trials) behind a fast-closing Julie Isphording. Even in ninth, Schiro’s time was an astonishing 2:34:24. It remains the American record for a junior runner, for a high-schooler, and for a 16-year-old Trials competitor. 

Tierney Wolfgram won’t find it easy to beat Schiro’s performance, especially not on the tough Atlanta course. Still many will be cheering for her to run strong and have a long career. You can debate whether or not 16-year-olds should be focusing on the marathon. But once they’ve made that decision, it’s hard not to root for them.

Schiro. Jeff Johnson photo
Postscript: Six months after her Marathon Trials appearance, Cathy Schiro enjoyed an unmatched cross-country season. In the Kinney Regionals in famed Van Cortlandt Park, she ran 16:46 on the 5K course, a record that still stands. Two weeks later, she won the Kinney Championships. In 1988 and 1992, Schiro finished third and second in the Marathon Trials, making two U.S. Olympic teams. Her best Olympic performance was 10th in the 1992 Barcelona Games. In 1991, she cracked 2:30 in the L.A. Marathon, running 2:29:38.

Currently, Schiro lives and runs (gently) in Durham, NH. Her son Patrick is a star distance performer at Dartmouth, while his younger brother, Andrew, has begun winning high school state championships on the track.