Like all good things, anything done in excess can have a negative side effect. The same can be said with marathon running.
While there are countless benefits to cardio, specifically running, like improved cardiovascular health, staving off some illnesses and its mood-boosting qualities (AKA runner’s high), there is some bad with the good. From chafing to knee/leg injuries and even cardiac arrest — one in every 184,000 marathon runners die from cardiac arrest following running — excessive running can actually be bad for you. Short-term kidney injury can be added to that list now, following a recent study published in the American Journal of Kidney Diseases.
Dr. Chirag Parikh led a team of researchers from Yale University that studied 22 runners who participated in the 2015 Hartford Marathon in Connecticut. The scientists took blood and urine samples one day before the race and again one day after the event, checking for levels of protein in the urine and creatine levels in the blood. Kidney cells were also examined under a microscope.
Results showed that 82 percent of participants had an increase in creatine level equivalent to acute kidney injury (AKI) stages 1 and 2.
“The kidney responds to the physical stress of marathon running as if it’s injured, in a way that’s similar to what happens in hospitalized patients when the kidney is affected by medical and surgical complications,” Dr. Parikh said.
Dehydration, increased core body temperature, and a drop in blood flow to the kidneys could attribute to the injury from running a marathon. The study showed the injuries were resolved within two days, but long-term effects are still in question.
“We need to investigate further,” Dr. Parikh said.
The key is to be smart and listen to your body. There’s such a thing as pushing yourself to the limit and then there’s pushing too far and risking injury. Take it from actual marathon runners.
“I would advise to read up as much as you can, then don’t listen to it,” former NFL running back/current marathon runner Tiki Barber said. “You have to find a way to understand what’s happening to your body so you can get your own feel, and it’s different for each person. Sometimes you read something and say, ‘That’s what I want to do,’ but it might not work for you. So read everything, then customize it to yourself and how you feel.”
“I’m definitely a risk taker, there’s no doubt about that, but I’m mindful of training in a smart way,” said trainer and fitness personality Robin Arzon. “… The authentic athlete in us says, ‘You can go harder and farther or you need to take a step back.’ I’ve listened to that over the years.”