marathons linked to acute kidney injury, study says, but it's ......2017/03/28 · therefore,...

Marathons linked to acute kidney injury, studysays -- but it's temporary

Updated 1631 GMT (0031 HKT) March 28, 2017By Jacqueline Howard, CNN

Photos: Crazy races that are fun to run

Crazy races that are fun to run – Tired of running on the treadmill day after day? These crazy races makepicking up the pace a lot more fun.

1 of 17

Marathons linked to acute kidney injury, study says, but it's tem... http://edition.cnn.com/2017/03/28/health/marathon-running-kid...

1 of 7 5/12/17, 4:10 PM

The physical stress of marathon running maybe linked to short-term kidney injury, a newstudy finds

Runners with kidney disease or takingibuprofen should be mindful of this potentialrisk, experts say

The benefits of long-distance running includeboosting your mood and longevity while reducingyour risk of cancer, diabetes and obesity.

Yet, running 26.2 consecutive miles also can stressthe body, leading to injury risk, a momentarilyweakened immune system, and now a small studysuggests acute kidney injury, too.

Marathon runners can develop short-term kidneyinjury during a race, but the kidneys repair

themselves within about two days, according to the study, which published in the American Journal ofKidney Diseases on Tuesday.

The findings, which need to be replicated in largerfollow-up research, suggest that some runners --including those with kidney disease, diabetes,hypertension; those taking anti-inflammatorymedications; and those older in age -- should bemindful of the way long-distance running mayimpact the kidneys.

"It's possible that marathon running could be anacute stress and may contribute to the progressionof existing chronic kidney disease, and this iswhere runners with this condition need to talk totheir physicians and talk to their trainers," said Dr.Chirag Parikh, a professor at the Yale UniversitySchool of Medicine and lead author of the study.

He added that, with adequate training, the kidneyscan adapt to such physical stress.

Related Article: Weird, gross andunexpected things that happen when yourun

ADVERTISING

Health + Live TV International Edition +


2 of 7 5/12/17, 4:10 PM

"I would think that the majority of marathon runners are doing OK because the 22 people whoparticipated in the study had normal kidney function and had been running marathons for an average of12 years," Parikh said. "So, if running marathons caused a great deal of permanent kidney injury, theserunners would have minimal kidney function remaining."

Marathon running in the United States has grownin popularity in recent years.

Between 1990 and 2014, the number of USmarathon finishers skyrocketed from about224,000 to a record high of 550,637, according toRunning USA, a nonprofit that tracks the number ofmarathon runners each year in an annual report.

Last year, about 507,600 runners finished amarathon in the United States, said Scott Bush, aspokesman for Running USA, which was notinvolved in the new study.

Kidneys show signs of damage, repairthemselvesRunners participating in the 2015 Hartford Marathon in Connecticut were recruited for the study and 22met the study requirements, as well as completed the study.

A day before the marathon, urine and blood samples were collected from the runners and analyzedunder a microscope. The researchers examined the samples for cellular changes and shifts in levels of acompound called creatinine, which is a marker used to diagnose acute kidney injury.

Related Video: Girl, 12, runshalf-marathon by mistake 01:32



3 of 7 5/12/17, 4:10 PM

from the runners and analyzed for signs of acutekidney injury.

"We wanted the blood drawn soon after themarathon, which is not an easy thing. Many of therunners are exhausted," Parikh said.

The researchers found higher-than-normal levels ofcreatinine in the urine and blood samples of almostall of the runners immediately after the marathon,with 82% of the runners showing signs of at leaststage 1 acute kidney injury.

"Almost everybody had a significant increase in thenovel markers of injury, inflammation, and repair,"

Parikh said.

The kidneys' responses to the stress of a marathonwere eerily similar to what Parikh said he wouldsee among patients who might be treated in ahospital for complications with medications thatimpact the kidneys, or who might be suderingkidney complications after cardiac surgery, forinstance.

"It was very surprising that the intensity of thefindings were similar," Parikh said.

About a day and a half after the marathon,samples again were collected, and they no longershowed signs of acute kidney injury.

"The good part was that we were able to confirmthat by day two or by 48 hours after the marathon,the findings returned to baseline," Parikh said.

'Be careful, think about it, and be prepared'The participants in the study were not taking non-steroidal anti-inflammatory drugs, such as ibuprofen,within 48 hours of the race, however such drugs can impact the kidneys and may put runners' health atrisk when combined with marathon running.

Dr. Malissa Wood, co-director of the Corrigan Women's heart health program at Massachusetts GeneralHospital and associate professor at Harvard Medical School in Boston, called the study findings "a realwake-up call."

"I do know these are people who are not taking non-steroidals, who are pretty well trained, and had anaverage finish indicating they had properly prepared for the marathon, and still 82%, had some kidney

Related Article: 70-year-old woman runs7 marathons on 7 continents in 7 days

Related Video: Running 100 miles in theicy Alaskan wilderness 02:07



4 of 7 5/12/17, 4:10 PM

"That just says to me, be careful, think about it, and be prepared," she said.

A limitation to the new study, besides its samplesize, is that the researchers didn't compare thefindings among their runners to other raceparticipants or marathon runners as a whole, saidDr. Martin Hodman, a health sciences clinicalprofessor at the University of California, Davis and afounding member of the Ultra Sports ScienceFoundation.

The study also didn't include a change in bodyweight as a way to get an assessment of howhydrated each runner was, Hodman said. He wasnot involved in the new study but has led separateresearch on acute kidney injuries followingultramarathon running.

"The fact that kidney injury markers werenormalized or improving within 24 hours should help alleviate fear of permanent kidney injury, andsupports what we have previously demonstrated," Hodman said about the new study.

The kidneys are temporarily impacted duringmarathon running for various reasons, one beingthat some of the blood supply kidneys typicallyreceive is being pumped to the body's musclesinstead of the organ, Parikh said.

"When someone runs 26 miles, the blood supply tothe skin and muscle increases tremendously,because they need a lot of oxygen," he said. "It'sestimated that up to 25% of blood ends up goingto skin and muscle, and when this happens, thatmeans the blood is getting diverted from otherorgans. So, while the skin and muscle are perfusedat a higher rate, the kidneys are receiving areduced blood supply."

The environment in which you are running can alsoinfluence how a marathon may impact your body, said Wood, the associate professor at HarvardMedical School.

Tips for runners"The truth is, when you're exercising for four hours, your body needs to maintain levels of glucose and itneeds to be hydrated, especially if you're running in a warm climate," Wood said. "Sixty to 70 degreesfor a marathon, that's warm, and 80 or 90 is really warm."

Related Article: 6 common mistakesnew runners make

Related Article: Ultramarathons goabove and beyond



5 of 7 5/12/17, 4:10 PM

Join the conversation

See the latest news and share yourcomments with CNN Health on Facebook andTwitter.

study, which was published in the journal Circulation in 2006.

"What we saw in our study was that if people didn'ttrain very much and they were sort of new tomarathon running they had a lot more leakage ofheart enzymes and it's a lot harder on their bodiesbecause they haven't been chronically exposed tothe conditions imposed by prolonged exercise,"Wood said. "Prolonged endurance exerciseincreases bloodflow to the leg muscles but canshunt blood away from the gut and kidneys."

Therefore, adequate training is key to minimizingany potentially harmful impacts marathon running can have on the body, she said.

Wood and Hodman, the professor at the University of California, Davis, both odered some tips for safelyrunning a marathon:

Pay attention to what your body is telling you during and after a run, Hodman said.When it comes to proper hydration, simply drink to thirst. By doing this, you will most likely avoidboth severe dehydration, which increases the risk of kidney injury, and overhydration, which canalso cause serious health issues, Hodman said.Wood added that many runners don't like to stop for water during a race due to fear that it maysignificantly adect their finish time, but "being dehydrated and exercising is really bad for yourorgans and your physiology," she said.Make sure that you eat breakfast the morning of a race, Wood said.Get a good night's sleep the night before a race, Wood said.Properly train before a marathon to avoid injury, Wood said.

"Generally, athletes recover without any need for specific medical intervention by simply rehydratingbased on their thirst," Hodman said about what to do after running.

"It's also important to keep this all in perspective," he said. "While there may be some risks withmarathon running, the lack of regular exercise among most of our population is far more dangerous andcostly to society than the overall risks from participation in marathon running."

Bananas tied to noose are foundaround American University campus

Parasites could belurking in your sushi

Not expected to livepast 10, he graduatescollege this week

3 US women share the



6 of 7 5/12/17, 4:10 PM

marathons linked to acute kidney injury, study says, but it's ......2017/03/28 · therefore,...

Documents