The muscular physiques of steroid-using athletes like A-Rod and Mark McGwire may make their fans’ hearts skip a beat, but these sports stars—and others who use anabolic steroids—may be setting themselves up for dangerous heart problems, according to a study published online in Circulation: Heart Failure and reported by HealthDay News.

For the study, researchers at Harvard Medical School and McLean Hospital used ultrasound to view the flow of blood through the hearts of 19 male weight lifters. Twelve of them reported using high doses of steroids weekly for years, and seven reported never using steroids.

Researchers found that most of the steroid users’ hearts pumped less blood with each beat and refilled with blood at almost half the normal rate of the nonusers.

“The number of persons in the study was small, and this needs to be studied in larger trials, but the data from this pilot study suggest that steroid use predisposes people to heart failure,” said Aaron L. Baggish, MD, the study’s lead author.

Heart failure, when the heart doesn’t circulate blood quickly enough to meet the body’s needs for oxygen and nutrients, is the No. 1 cause of cardiac deaths.

Baggish also stressed that it’s not just long-term steroid use that’s dangerous. Existing studies and reports show that even short-term use can have devastating effects, both to heart health and to overall wellness.

“When you add up all of the organ systems that steroids damage—and the heart is just one important organ—the logical recommendation is that steroid use is a no-no for cosmetic or athletic purposes,” Baggish said.

Click here for information about teens’ health risks when they use steroids.