How To Protect Your Kidneys During Your Next Marathon
Most runners are very careful to protect their muscles and joints during their training. But don’t forget the kidneys!
It is known that unusually vigorous activities can lead to kidney damage. Research in the past has focused on people who are involved in mine work, harvesting, and military training – especially in warm weather. So far, though, there has not been much research on marathon runners.
Researchers at Yale, led by Professor Chirag Parikh MD, has found that the physical stress of running a marathon can indeed cause short-term kidney injury. Thankfully though, most runners achieve a full recover within two days.
Dr. Parikh studied participants in the 2015 Hartford Marathon. The team analyzed blood and urine samples for markers such as serum creatinine levels and proteinuria (protein in the urine). Creatinine is a chemical waste molecule that is generated from muscle metabolism and is a reliable indicator of kidney function. Having protein in the urine is another indicator of kidney damage, as healthy kidneys do not allow for much protein to pass through.
More than 80% of the runners studied had indicators of Stage 1 Acute Kidney Injury (AKI), traditionally defined as the abrupt loss of kidney function. Potential causes of the damage are the sustained rise in core body temperatures, dehydration, or decreased blood flow to the kidneys during extreme physical activity.
"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 Dr. Parikh.
The research is especially timely because more Americans are running long distances. In fact, in 2015, more than half a million people participated in a 26.2 mile race. In addition to potential kidney function concerns, other studies note changes in heart function that can occur with marathon running.
What the research does not tell us, however, is if the effect is cumulative over time (meaning additional injury with each subsequent marathon) or if the kidneys ultimately adapt – much like your muscles can adapt to the stress of running.
Until then, it is wise to ensure your training program includes a strategy for adequate hydration during a marathon. Also, take steps to prevent overheating – do not overdress for the day’s weather. And if you have a personal or family history of kidney disease, ensure you speak with your doctor about your marathon running.
Dr. Cathy Fieseler, a sports medicine doctor in Texas, also suggests avoiding anti-inflammatory drugs before the race, including ibuprofen (Advil, Motrin) and Naproxen (Aleve) as these are cleared through the kidneys. Acetaminophen (Tylenol) is cleared through the liver.
Sherry G. Mansour, Gagan Verma, Rachel W. Pata, Thomas G. Martin, Mark A. Perazella, Chirag R. Parikh. Kidney Injury and Repair Biomarkers in Marathon Runners. American Journal of Kidney Diseases, 2017; DOI: 10.1053/j.ajkd.2017.01.045
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