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What Do Marathon Runners' Bodies Go Through?

Runners approach the finish line of the Boston Marathon on April 16, 2018.
Meredith Nierman/WGBH News

Judy Yuill: It takes a lot to prepare for the Boston Marathon — months of training, hundreds of hours of hard work. It's all taxing on the body, but what about the actual race? Here to explain the effects of marathons on the human body and what runners can do to take care of themselves after they cross the finish line is Dr. Malissa Wood. She's a cardiologist at Mass General. Thanks for joining us, Dr. Wood.

Wood: Thank you.

Yuill: So what happens to a runner's physique when they push themselves to finish a 26.2 mile race? Give us a rundown on what that's like for their body.

Wood: So I think if we started at the head and work to the toes, the first thing is people are pretty mentally fatigued after running a marathon. It takes a lot of time, determination, and stamina to finish the race, and so I think people may feel not only really emotionally drained, but also just physically drained. The cardiac effects include, you know, sort of the heart rate being high, a lot of increased cardiac output for the between two-and-a-half to five hours that it takes for most people to finish. So their heart rate will be a little bit higher, their blood pressure might be a little bit lower, and they really need to make sure that they replenish not only fluid, but certainly the electrolytes that are lost during the course of a marathon.

Now if we get into the bowel, a lot of times people have a little bit of tummy distress when they're running just because blood flow is actually diverted from the gut to your leg muscles. So a lot of times, people will really need to kind of take it easy in what they eat afterwards and recognize that sometimes the digestive system may take a day or two to recover.

The muscles, as we know, certainly are very sore and a massage, if you can get one afterwards, definitely helps. But a lot of stretching and certainly walking after finishing is important. A lot of people just cross the finish line and, you know, go to their hotel room and take a nap, and that's probably not the best thing to do, because those legs have worked really hard and they need to be stretched.

Now with regard to the toes and the other parts of the body, where there's a lot of contact between the skin and, say, the arms or near the feet, there may be blisters. So you really need to pay attention to those blisters, make sure that they're clean and dressed appropriately — especially, you know, for the next couple days when you're going to be walking around, and just kind of checking your body overall to make sure that things are sort of moving OK. If there's anything that really feels abnormal like, you know, bad knee pain, back pain, etc., it should be checked out when people get back home.

Yuill: It seems like today's weather, the combination of the wind, the rain, the cold, would pose some extra challenges for runners. What are they going to be contending with after a race in these conditions?

Wood: So I think the conditions today with the wind, the rain, and the cold would lead for a lot more hypothermia. So people will really need to pay attention that after the race, they drink plenty of warm fluids, that they definitely eat, and that they stay nice and warm — even taking a nice warm shower. It takes a while to warm the body back up after being outside, in cool windy conditions. And you know, I think it's especially important to remember that your cardiovascular system works extra hard today if you ran the marathon, because not only did you have to get to the finish line, but you had to kind of keep your body warm while doing that. And so your body was really working hard trying to deliver blood flow to the right places to maintain the normal body temperature.

Again, muscle stiffness is probably going to be even more of a problem because the muscles get very tight when you stop running, and it's cold outside. So that massage and that extra stretching will really go a long way, especially on a day like today.

Yuill: It struck me that wet socks and wet running shoes could chafe and cause blisters and just make a miserable condition for the runners’ feet.

Wood: Oh, most certainly. I think, you know, most people can prepare in advance to kind of preemptively protect themselves from these types of blisters. But then again, doing a check over your body afterwards and making sure that you kind of know what’s injured, treat it appropriately, and take a few days rest before you get back out on the road.

Yuill: Now we've talked about how taxing it is to run a marathon, but are there any benefits?

Wood: There are many benefits. I mean, first and foremost, I think the preparation for running a marathon means that, if you did it the right way, you've been out there training with a plan for a long period of time. That might also include training with other people, and we know that exercise with a group of people is such a positive benefit for the health, it really gives you sort of that social support.

And we know that people tend to have, you know, stronger muscles, better cardiac endurance, and overall a better outlook when they are training for something like a marathon. Especially for those people who cross the finish line for the first time, it’s such a sense of accomplishment and I think it really is such an invitation to continue life-long exercise. I think, you know, there are so many benefits, and we really want to stress that the majority of benefits are so worth the pain that you go through for that four-and-a-half or however many hours it takes to get to the finish line.

Yuill: OK, thanks for joining us Dr. Wood.

Wood: Thank you very much.

Yuill: That's Dr. Malissa Wood. She's a cardiologist at Mass General.


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