4 Symptoms to Heed if You Exercise While on Statins

Q: I'm taking statins and have been advised to be on the alert for muscle problems that may occur when I exercise. But if I'm doing challenging workouts, how can I tell the difference between soreness caused by the exercise and soreness caused by the statin? I do weight training and push during cardio workouts such as hiking, spinning or on cardio machines.

A: First of all, you should realize that muscle problems, also known as myopathy, are considered to be fairly infrequent. A 2010 review in the journal, Current Atherosclerosis Reports, estimated that from 5 to 15% of statin users have experienced myopathy. Also, statin-induced myopathy can occur even if you are not exercising, and it's unclear whether exercising while on statins can trigger or worsen muscle problems (I wrote more about that here).

"Eccentric" exercise is thought to be a potential trigger for statin-induced myopathy. Eccentric muscle contractions occur when muscle lengthen against resistance. Muscle fibers (or muscle cells) are each a certain length. When they contract, they shorten and this is known as the concentric part of a muscle contraction. This shortening brings bones closer together, bending the surrounding joint in some way.

When the joint opens up again, and the fibers lengthen again, if there is some resistance present, a tightening-while-lengthening occurs. This is the eccentric contraction of the muscle.

Eccentric contractions occur when you lower a weight from having lifted it while doing a biceps curl, for example. As you lower a dumbbell, gravity wants to pull it down so your muscle tightens a bit to prevent it from slamming to the ground. The biceps and other arm muscles are lengthening to lower the weight and straighten the elbow, but they are doing it slowly, and with some tension, to prevent the weight from plopping down.

Walking downhill produces the same eccentric-contraction effect on the leg muscles. Since gravity and the downward slope are encouraging your body weight to tumble down, your muscles tighten to stay in control so you don't stumble down the hill.

Many weight lifters purposely accentuate the eccentric part of an exercise by either going more slowly or adding extra weight in order to increase their overall challenge to the muscles. Eccentric exercise is more apt to lead to muscle soreness. So this might suggest that a tougher-than-normal stimulus might be a stronger trigger.

Statin-induced myopathy can include tangible symptoms such as muscle aches, pains, muscle fatigue or weakness. But statin-related myopathies can also go undetected because they can also appear in blood tests only, without any noticeable physical symptoms. Creatine Kinase (CK) is an enzyme that is involved in muscle breakdown. If levels are elevated past a certain range it is considered a sign of muscle damage. At very high levels, kidney failure and even death can result.  While signs of rising CK can occur from statin use and signal myopathy, challenging exercise can also raise levels of CK (although this is more likely from running marathons, not 45 minute bouts on a stairclimber.) Of course, most people don't immediately get blood tests to check for this, especially if they think they're just sore from a workout.

A 2010 review in the journal, Physical Therapy identified ways to screen for potential statin-related muscle problems. Here are some potential red flags that you should be on the lookout for:

Where are you sore?

If muscles that you did not work out feel sore, then it may not be the exercise that caused it.

What type of exercise were you doing that led to muscle soreness?

It's unlikely that you'll feel sore from cardio, unless you hiked up steep hills or really cranked up the resistance or speed on a machine. Resistance training, lifting weights or using bands, targets specific muscles more directly and so can make you a little sore.

How sore are you?

While lifting weights can make you sore, if you get so sore you feel debilitated, that's a sign that you either pushed too hard, or perhaps the statins are having a muscle side effect.

How long is your soreness lasting?

Muscle soreness from hard exercise generally goes away within 2 to 3 days…so if you have lingering and chronic, or worsening, soreness, consult with your doctor.

If you spot any of these red flags while you are taking statins and working out, consult with your doctor.