Researchers at the Cleveland Clinic studied 122,007 patients who underwent treadmill testing between 1991 and 2014. They found a sedentary lifestyle is worse for your health then smoking, diabetes or heart disease.
Dr. Wael Jaber, a cardiologist and senior author of this study, called the results "extremely surprising."
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"Being unfit on a treadmill or in an exercise stress test has a worse prognosis, as far as death, than being hypertensive, being diabetic or being a current smoker," Jaber told CNN. "We've never seen something as pronounced as this and as objective as this."
Another big revelation from the research is that fitness leads to a longer lifespan.
Researchers have always been concerned that people who exercise excessively might be at higher risk of death, but the study found that not to be the case.