Some Runners Are Testing the pH of Their Pee—Should You?

During a recent interview with Outside RUN, legendary ultrarunner Killian Jornet mentioned in passing that he tests his urine pH to look for muscle damage after intense training and racing sessions as he prepared for his incredibly ambitious States of Elevation project, where he summited the 67 (give or take) 14,000-foot peaks in the lower 48.

Wait. Say what?

Of course, we wondered: Is this something we should be doing too? How do you do it? And what the heck can your pee’s pH tell you about how your body did during an effort and how it might recover?

What You Need to Know About pH

The pH scale measures a substance’s acidity or alkalinity, ranging from 0 to 14, with lower numbers indicating greater acidity. A neutral pH level is 7—think pure water—so anything lower than that is considered acidic and anything higher is considered alkaline.

At the alkaline end of the scale, liquid drain cleaner registers at pH 14, bleach at 13, and household ammonia at 11. Seawater, blood, and eggs usually clock in at about 8, while toothpaste and hand soap land at a 9 on the scale.

At the acidic end of the spectrum, battery acid registers at 0, while hydrochloric acid is 1, and lemon juice and vinegar are about a 2 on the pH scale.

The pH of Urine

Urine typically registers about 6 on the scale—so slightly acidic, but on the same level as saliva and milk. Normal urine pH readings can range from about 5.5 to 7.5 for most people, but even as low as 4.5 and as high as 8 is usually not much cause for concern.

When urine pH falls outside the normal range, it may indicate kidney problems, an infection, or another issue. Some medications can also alter the pH of your urine, either masking a problem or suggesting one that isn’t there.

What the pH of Your Urine Says About Your Health

Because of the extended time spent exercising, sweating, and losing water and electrolytes during activity, endurance athletes are at higher risk of several potentially life-threatening complications, including:

• Dehydration
• Acute kidney injury
• Exercise-associated hyponatremia (an abnormally low concentration of potassium in the blood)
• Heat exhaustion and heat stroke
• Rhabdomyolysis (a rare condition often related to overexertion; it causes the muscles to break down and can lead to kidney damage)

Testing urine pH with test strips is a simple, affordable way to get quick insights into whether any of these conditions may be present.

Kidney Health and Performance

It’s important to note that there’s nuance in how urine test results should be interpreted, says clinical nephrologist Dr. Raeeda Gheewala, founder and CEO of Sports Nephrology Peak Performance and Health, based in Texas. Also known as “The Kidney Queen,” Gheewala works with athletes to optimize kidney function for improved performance.

“As a sports kidney expert, I interpret urine studies every day,” Gheewala says. And those results can vary from day to day and even multiple times per day for the same athlete. Over time, test results build a picture of what’s going on in the body. “Having multiple data points across time increases the utility of the test and strengthens my conviction to intervene upon the result,” she says.

Why Endurance Athletes Can Benefit from Testing Their Urine’s pH

The kidneys are critical to maintaining pH balance in the body, Gheewala explains. “A urine pH test provides the acid-base status of a person’s urine, which is a surrogate for the amount of dietary acid load ingested from amino acids and animal protein for that snapshot in time.”

For endurance athletes, this can be important information to track because, during exercise, the body produces lactic acid as a byproduct in the blood, which needs to be filtered and excreted as a toxin by the kidneys.

A low pH after intense training could indicate that acid load has increased, but these changes don’t manifest immediately—it usually takes several hours for this evidence to show up, Gheewala notes. In addition, low or persistently low urine pH readings can signify a need to reduce the dietary acid load to reduce strain on the kidneys, she says.

Urine pH testing can also indicate whether an athlete is at risk of developing kidney stones or if they’re already present.

Perhaps the most utilitarian application for urine pH testing is to provide insight about how best to balance water and electrolyte intake during endurance exercise.

“Exercise-associated hyponatremia is a common condition marathon runners experience, which can manifest as mild headache or confusion and progress to seizure and brain swelling,” Gheewala says. But balancing your intake can help you avoid that.

If you’re considering adding urine pH testing to your training approach, check in with a health care provider first to ensure you’re doing it right and interpreting results correctly. A sports medicine specialist can also help you more finely tune all of the inputs that can help you level up in your running.

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