Sitting too much might not just give you a big belly—it can also raise the red flag for your prostate health. As your activity level drops, your blood levels of a certain protein linked to prostate cancer spike, according to research published in the Journal of Physical Activity and Health.
The researchers measured the participants’ physical activity levels, and found that men with an extra hour of sedentary time in their day had a 16 percent greater chance of having elevated prostate-specific antigen (PSA) levels. On the other hand, guys with an hour more of light physical activity per day were 18 percent less likely to have big PSA scores.
Now, this study didn’t measure rates of prostate cancer in these guys with spiked PSA levels, so we can’t definitively say that sedentary behavior causes cancer. But it’s a possibility, says study coauthor Manish Kohli, M.D., an associate professor of oncology at the Mayo Clinic.
A possible explanation: Sitting around could fatten you up, which could flood your body with sex hormones, inflame body tissue, and increase your resistance to insulin—all of which may contribute to the development of prostate cancer, he says.
How Does PSA Relate to Cancer?
PSAs are proteins formed by cells in the prostate gland. Previously, elevated PSA levels acquired from a simple blood test were believed to be a huge red flag for prostate cancer, says Dr. Kohli.
Nowadays, most doctors know that high PSA levels could be false alarms to cancer. The big C isn’t the only thing that can cause these levels to rise—benign conditions like inflammation, infection, or enlargement of the prostate can increase them, too.
In the past, high PSA levels have been used as a reason to biopsy the prostate. But biopsies are invasive and can really freak guys out, says Dr. Kohli.
So a man who is more sedentary could be put through the torment of these tests only to find out he doesn’t have cancer. And on the flip side, some extremely active guys may have benefited from a biopsy because their activity could have dropped their PSA to a level that appears to indicate no prostate cancer, he says.
The solution: Knowing that our amount of physical activity can affect our PSA levels, docs should take that into consideration—along with medications, family history, and prostate exam results—when determining who actually needs a prostate biopsy, says Dr. Kohli. That means not relying solely on a high PSA number.
“What we have to do is at least inform our patients that there are reasons for PSA level fluctuations,” says Dr. Kohli.
What Does This Mean for You?
That raises the question: Should You Get a PSA Test? According to the U.S. Preventive Service Task Force, the answer is no—it changed its guidelines in 2012 to recommend against PSA-based routine screening for prostate cancer.
But hold up: Not everyone agrees with the U.S. Preventive Task Force. Other medical organizations, like the American Urological Association, thinks it can be valuable.
PSA testing is still useful, says Larry Lipshultz, M.D., a urology advisor for Men’s Health. “It’s the best (screening) test we have right now,” he says. And that’s important, because unlike many other cancers, prostate cancer grows pretty silently, so you may not notice any symptoms until it has spread.
When would your doc order up the test? If you get abnormal results from a digital rectal exam and or you’re in your 40s or 50s and have a higher risk due to family history, race, or health conditions like high blood pressure, says Dr. Lipshultz.
Bottom line: PSA levels can provide an important piece of information for your doctor when deciding whether to biopsy your prostate—it just shouldn’t be the only one, says Dr. Lipshultz.