How to Build a Marathoner’s Body in 6 Not-So-Easy Steps

Elite men runners leave the start line in the 118th running of the Boston Marathon Monday, April 21, 2014.
Elite men runners leave the start line in the 118th running of the Boston Marathon Monday, April 21, 2014.

Logging mileage can lead the brain to release feel-good hormones that boost your mood and overall health. But a 26.2-mile run isn’t all bliss. Your body gives off a whole slew of other molecules, too, including toxins like lactate dehydrogenase and myoglobin, says Jen Schwartz, M.D., a runner and sports medicine doctor at Beth Israel Deaconess Medical Center.

The good news: The right build — from a sharp brain to a strong heart — can filter the bad stuff out, keep the good stuff flowing, and propel you toward the finish. But a better body doesn’t just take training — it takes the right kind of training.  

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Build your brainpower.

There’s a reason elite athletes train their brains just as hard as their bodies: “Going the distance requires a high level of mental toughness. And maintaining motivation during the training period — and the race itself — can be a challenge,” says Eric Endlich, Ph.D., a Boston-area psychologist who helps people with sports, exercise, and health concerns.

And the majority of a runner’s mental fitness comes from the training itself, says Terrence Mahon, a Boston Athletic Association high-performance coach.

“Persevering during three to four months teaches an athlete to be committed, patient, and to weather the storms of fatigue, soreness, and self-doubt,” Mahon says.

Eat for the body you need.

With extra mileage comes extra calories — and most training marathoners need to take in an extra 70 to 100 calories per mile they run, says Krista Austin, Ph.D., who worked with 2014 Boston Marathon winner Meb Keflezighi.

“I usually say give yourself 70 calories for every easy mile you run, and 100 for every hard mile.” Exact numbers depend on the individual, but the most important factor is incorporating food in at slow and steady rate — the same way you should build training volume, she says.

What should you eat? It varies per person, but Austin ballparks it like this: 45 to 70 percent of calories should come from carbs, 10 to 30 from protein, and 15 to 35 from fat.

Solidify your strength.

“Distance running is brutally honest — it will show you any biomechanical inefficiencies that you need to overcome,” says Sara Walker, a Boston-based running coach and seven-time marathoner.

That’s why one of the most important facets of training is building a strong foundation beyond the pavement. The best marathon runners are comfortable with general strength training.

“The core transfers energy back and forth between the arms and legs as efficiently as possible,” says Mahon.

If it’s weak, the hips will drop and the arms will rise, creating muscle imbalances and overuse injuries, he says.

“The upper body can contribute 25 to 30 percent of the work toward overall running speed,” says Mahon. “To neglect this in training is to leave a lot of minutes back on the course.”

Pump up your heart with variety.

Your ticker is the primary determinant of how much you can exercise, says marathoner Aaron L. Baggish, M.D., associate director of Mass General Hospital’s Cardiovascular Performance Program. During training, your heart adapts to be more efficient, he says: It grows in size and becomes more capable of handling high heart rates.

“Your heart is kind of a blind organ — it doesn’t know the difference between running, cycling, or rowing, so cross-training can be highly effective,” Baggish says.

As long as your heart rate is up for an extended period of time, your heart will remodel and adapt, he says. All the more reason to shake things up.

Breathe better.

“When training, your ability to take in and use oxygen gets better — that’s called a VO2 max,” says Schwartz.

Running consistently and aerobically helps to enhance oxygen delivery and extraction, she adds. But part of a better VO2 max also stems from how well you breathe.

“Focus on abdominal breathing — not shallow chest breathing,” she says. Put your hand on your stomach — you should feel it get bigger when you breathe in and smaller when you breathe out.

“This can help strengthen the diaphragm and get more oxygen in,” she says.

Coordinating breaths with foot strikes can help you breathe deeper and more slowly, and control your heart rate, too, she says. Researchers in England found that runners whose breathing was the most strained also had the most weakness in their legs.

Optimize your lung capacity.

“Optimal lung capacity is built in two ways,” says Mahon. 

Running greater distances helps add volume to build out your aerobic system, he says. The second way is running harder — at 85 to 95 percent of your max heart rate for shorter bursts, in interval training or tempo runs. The ultimate goal is a large lung capacity and a high power output.

“This will teach the lungs and heart to become more efficient at shuttling oxygen and blood to and from the working muscles,” Mahon says. “If we look at the lungs like a car engine, then we want to build out that V8 engine, but have a lot of horsepower — all the while trying to use the least amount of gas as possible.”

Read more coverage of the 2015 Boston Marathon.