Statins are supposed to help protect hearts, but NPR reported Monday that a recent study shows that statin patients are less likely to be active than patients who don’t take the cholesterol fighters. This is a bit of a problem, in that both exercise and statins can be part of a heart-healthy regimen.

NPR says researchers are not sure why patients may be moving less, and note the possibilities could include the sometimes-reported association between muscle pain and statin use, as well as the fact that patients may be taking it easier because statins are doing some of the work exercise did. The study found activity levels dropped the most in the first year of taking the medications, compared to before patients started the prescriptions.

Just how much of the drugs should be taken is also up for grabs—Reuters reported Monday that stroke and heart-attack patients taking high doses of statins—10mg or more of Crestor, 20mg or more of Lipitor, 40mg or more of Zocor—had a 15% greater risk of being diagnosed with diabetes than patients taking lower doses of these medications. Researchers are not clear why this is happening.

“This is not about stopping statins… the question is, should they be on a higher or lower dose?” lead researcher Colin Dormuth told Reuters.