Statin drugs are the most widely prescribed drugs worldwide. Many experts believe statins are overprescribed, however, and studies continue to find that statins are not the miracle heart drugs they are painted to be. Two recent studies add to the evidence that statins are not for everyone. Here’s why.

The first study, published in the Journal of the American College of Cardiology, measured cardiorespiratory fitness in previously sedentary, obese individuals, half of whom were taking statins. What they found suggests statins may actually interfere with heart health in an indirect way. Those participants who only exercised increased their cardiorespiratory fitness by 10 percent compared to only 1.5 percent in those also taking a statin.

“Fitness has proven to be the most significant predictor of longevity and health because it protects people from a variety of chronic diseases,” stated John Thyfault, PhD, lead researcher. “Daily physical activity is needed to maintain or improve fitness, and thus improve health outcomes. However, if patients start exercising and taking statins at the same time, it seems that statins block the ability of exercise to improve their fitness levels.”

“Statins have only been used for about 15 to 20 years, so we don’t know what the long-term effects of statins will be on aerobic fitness and overall health,” he continued. “If the drugs cause complications with improving or maintaining fitness, not everyone should be prescribed statins.”

The bad news for statins doesn’t end there. Another recent study published in the British Medical Journal found that certain high potency statins increase the risk of developing diabetes. Researchers looked at data from over 470,000 people treated with statins. Over half of all new statin prescriptions were for atorvastatin, followed by rosuvastatin, simvastatin, pravastatin, lovastatin, and fluvastatin.

Patients taking atorvastatin had a 22 percent increased risk of developing diabetes, while those taking rosuvastatin had an 18 percent increased risk when compared to those taking pravastatin. Patients taking fluvastatin and lovastatin had a 5 and 1 percent decreased risk, respectively. I blogged last year about the link between statin drugs and type 2 diabetes in women. This just adds to the evidence that statins aren’t all that they’re touted to be. Fortunately, lifestyle factors like healthy diet and exercise can reduce cholesterol and improve heart health all on their own.