Marathon running may cause short-term kidney injury

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PUBLIC RELEASE: 28-MAR-2017
Marathon running may cause short-term kidney injury
YALE UNIVERSITY
New Haven, Conn.-- According to a new Yale-led study, the physical stress of running a marathon can cause short-term kidney injury. Although kidneys of the examined runners fully recovered within two days post-marathon, the study raises questions concerning potential long-term impacts of this strenuous activity at a time when marathons are increasing in popularity.

The study was published March 28 by the American Journal of Kidney Diseases.

More than a half million people participated in marathons in the United States in 2015. While past research has shown that engaging in unusually vigorous activities -- such as mine work, harvesting sugarcane, and military training -- in warm climates can damage the kidneys, little is known about the effects of marathon running on kidney health.

A team of researchers led by Professor of Medicine Chirag Parikh, M.D. studied a small group of participants in the 2015 Hartford Marathon. The team collected blood and urine samples before and after the 26.2-mile event. They analyzed a variety of markers of kidney injury, including serum creatinine levels, kidney cells on microscopy, and proteins in urine.

The researchers found that 82% of the runners that were studied showed Stage 1 Acute Kidney Injury (AKI) soon after the race. AKI is a condition in which the kidneys fail to filter waste from the blood.

"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," said Parikh.

The researchers stated that potential causes of the marathon-related kidney damage could be the sustained rise in core body temperature, dehydration, or decreased blood flow to the kidneys that occur during a marathon.

While the measured kidney injury resolved within two days post-marathon, the study still raises questions about the effects of repeated strenuous activity over time, especially in warm climates.

"We need to investigate this further," said Parikh. "Research has shown there are also changes in heart function associated with marathon running. Our study adds to the story -- even the kidney responds to marathon-related stress."

 

PUBLIC RELEASE: 7-JUN-2017
Excessive exercise may damage the gut
WILEY
A review of published studies has found that people who exercise excessively may be prone to acute or chronic gut issues.

Investigators found that with increasing intensity and duration of exercise, there was a proportional increased risk of gut damage and impaired gut function. Specifically, the cells of the intestine are injured and the gut becomes more leaky, allowing pathogenic endotoxins normally present and isolated to the intestine to pass into the bloodstream. This scenario of 'exercise-induced gastrointestinal syndrome' may lead to acute or chronic health complications.

Exercise stress of 2 hours at 60% VO2max appeared to be the threshold whereby significant gut disturbances arise, irrespective of an individual's fitness status. Running and exercising in hot ambient temperatures appear to exacerbate the gut disturbances.

The review also found that for patients who have irritable bowel syndrome or inflammatory bowel disease, low to moderate physical activity may be beneficial. The health implications of more strenuous exercise has not been researched, but is likely to be detrimental for such patients.

"Despite excessive exercise being confirmed to compromise gut integrity and function, we have identified several exacerbating factors which can be controlled, and several prevention and management strategies that can attenuate and abolish the damage and compromised function," said Dr. Ricardo Costa, lead author of the Alimentary Pharmacology & Therapeutics review. "It is recommended that a full gut assessment during exercise should be undertaken by individuals with symptoms of gut disturbances during exercise, to ascertain what is causing the issue and to develop individually tailored management strategies."

 

That does not mean marathon are bad, they can put pressure to kidneys but with maintaining balance to this act the risk are minimized.

 

PUBLIC RELEASE: 7-JUN-2017
Running multiple marathons does not increase risk of atherosclerosis
Health of blood vessels depends solely on age
Sophia Antipolis, 7 June 2017: Running multiple marathons does not increase the risk of atherosclerosis, according to research published today in the European Journal of Preventive Cardiology.1

"There has been a debate over whether intensive endurance exercise such as marathon running may be dangerous for the heart," said lead author Dr Axel Pressler, Head of the Prevention Centre, Technical University of Munich, Germany. "Previous studies found that after running a marathon, the same cardiac biomarkers were acutely elevated as after a heart attack."

"Other research discovered increased coronary atherosclerosis in marathon runners as a potential chronic consequence of running" he continued. "However, this may have been due to exposure to traditional risk factors such as current or past smoking."

This study aimed to find out whether running itself could induce the early development of atherosclerosis. It therefore included only healthy men without any history of cardiovascular risk factors such as cardiovascular disease, hypertension or smoking.

Pre-atherosclerotic changes to the function and structure of the blood vessels were evaluated by increased stiffness of the arteries, increased intima-media-thickness (due to early atherosclerosis), and endothelial dysfunction, which indicates an impaired reaction of the vessel to blood flow.

The study included 97 participants of the 2013 Munich marathon who had already completed multiple events. Each participant did an exercise capacity test to measure peak oxygen uptake, and gave their training history. The finishing time for the marathon was recorded for each runner.

Measurements of arterial stiffness, intima-media-thickness, and endothelial dysfunction were taken before and after the event.

Prior to the current marathon, participants had successfully finished a median of 11 running events which included half marathons, full marathons, and ultramarathons. The average weekly and annual training distances were 59 km and 1 639 km, respectively.

Runners had normal mean values for arterial stiffness, intima-media-thickness, and endothelial dysfunction. There was no association between exercise capacity, marathon finishing time, number of completed races, or weekly and annual training distances with arterial stiffness, intima-media-thickness, or endothelial dysfunction.

The only characteristic of the runners that was independently associated with the three measurements of pre-atherosclerosis was age.

"When we get older our arteries get stiffer and are not so elastic anymore," said Dr Pressler. "Our study shows that runners who have finished 20 marathons do not have stiffer arteries or more impaired vessel function than people of the same age who have finished five or zero marathons."

"We can conclude that marathon running itself is not a risk factor for atherosclerosis," continued Dr Pressler. "It appears that you can run as many marathons as you want and not be in danger of developing impaired blood vessel function or atherosclerosis."

While running multiple marathons did not have a deleterious effect on the blood vessels, it did not have a positive effect either. Dr Pressler said: "Running had a neutral effect on the blood vessels. The state of the blood vessels in these runners depended solely on their age."

The findings are good news for runners, but Dr Pressler warned that marathons do put strain on the body and participants should ensure they are prepared through training, nutrition, and appropriate hydration.

He concluded: "Many people are interested in marathon running and are doing ambitious recreational sports. Our study shows that running multiple marathons is not risk factor for atherosclerosis."