May 24, 2013
A small new study suggests that taking a statin drug to lower cholesterol may reduce some of the positive effects of exercise. The study included 37 people who were overweight or obese. They had high blood pressure, large waist size or other factors that increased their risk of heart disease. They had slightly high levels of LDL cholesterol and did not exercise regularly. Researchers randomly divided them into 2 groups. Both groups completed a 12-week program of supervised exercise. One group also took 40 milligrams of simvastatin daily. After the 12 weeks, people who did not take statins showed a 10% improvement in their aerobic fitness. Those taking statins improved by only about 1%. Researchers also took samples of muscle tissue. They found that people who did not take statins had a 13% increase in activity by mitochondria. These are the parts of cells that turn oxygen and glucose into energy. The numbers fell 4.5% for those taking statins. The Journal of the American College of Cardiology published the study online. The New York Times wrote about it May 22.
By Mary Pickett, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Statins are trusted medicines for lowering cholesterol. They are the most widely prescribed medicines in the United States. But is it possible that they might interfere with your physical fitness? A small study makes us worry. In the study, people taking statins didn't get the same results from exercise as people not on the drugs.
This study supervised people in a 12-week, almost-daily exercise program. All of them were overweight. They also had conditions that increased their risk of heart disease.
Eighteen people were given 40 milligrams of simvastatin each day. A similar size group was kept off of the medicine. All of them exercised. People who took statins gained less muscle mass. Their physical fitness also improved less. (To determine fitness, the researchers measured oxygen use during exercise. This is a measure of muscle activity.)
At the end of the program, biopsy samples were taken from a muscle. In people who had been exercising without a statin, the muscles had a 13% increase in activity by mitochondria. Mitochondria convert glucose and oxygen into energy. Among those who took statins, on the other hand, mitochondrial activity decreased 4.5%.
Do statins blunt the benefits of exercise? Is this a realistic worry? Perhaps. The study is very small, and it was very short. But it is raising some concerns.
One reason this study is worrisome is that it fits a picture that has been building for some time. We have known from the beginning that statins are not always easy on the muscles. They can cause muscle aches in 5% or more of people who take them.
Athlete studies have also led to worrisome reports. In one study, Boston marathon runners who were taking statin drugs had a higher creatinine kinase (CK) level in blood tests than runners who were not on statins. This was a sign of muscle stress or breakdown.
Another study has reported a higher rate of complaints about statin side effects among people who are involved in an "intense form of sport" than among less physically active patients. When professional soccer players were studied, only 20% of 22 players who had high cholesterol were able to tolerate a statin drug.
What Changes Can I Make Now?
Exercise is superb for heart health. Statins are also good for heart health. But if you might get less return on your efforts when you put them together, what should you do?
For starters, do not give up on exercise if you take a statin. Unless your doctor advises you to do so, don't stop your statin, either. So far, from what we see, people with heart disease who exercise and take statins are still better protected over the long term than those who do one without the other. This has been shown in a large study of veterans.
Because this new study about exercise is so short and so small, we can't draw definite conclusions from it. We also can't see important outcomes, such as rates of stroke, heart attack or death.
Even as we learn more about how statins may affect muscles, it is hard to argue with the proven benefits of these drugs. Statins are recommended for anyone who has had a prior heart attack or stroke. They are also recommended for people who are at very high risk for having a heart attack. This includes people who have multiple factors that increase their risk of heart disease.
We know from reliable studies that when high-risk people take them consistently, statins result in:
If you have never had a heart attack, and your heart risk is only slightly above average, will taking a statin help you to live longer? Probably not. In this case they don't have a clear benefit.
I always ask my lower-risk patients to increase exercise as a first step to lower high cholesterol. Most of them agree with the idea of holding off on the statin drug until we see if exercise, diet and weight loss lower their cholesterol. If a stepped-up exercise program lowers your cholesterol to a safe level, then there is less need for a statin.
Talk to your doctor if you are taking a statin and you notice muscle pain or weakness. If you have had symptoms for longer than two weeks, it is reasonable for your doctor to recommend a break from the statin. If your symptoms go away quickly, and come back when you restart the medicine, then the symptoms may be side effects.
What Can I Expect Looking to the Future?
We need to collect more information about statins and exercise. So far, no study looking at this topic has been large, and none has looked for long-term effects. This leaves us with some important questions.
The National Heart, Lung and Blood Institute has been working toward the release of an updated guideline about cholesterol treatment. Watch for this in the coming months.
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