Prolonged Moderate-Intensity Exercise Does Not Increase Muscle Injury Markers in Symptomatic or Asymptomatic Statin Users

Summary

Background: Statin use may exacerbate exercise-induced skeletal muscle injury caused by reduced coenzyme Q10 (CoQ10) levels, which are postulated to produce mitochondrial dysfunction. Objectives: We determined the effect of prolonged moderate-intensity exercise on markers of muscle injury in statin users with and without statin-associated muscle symptoms. We also examined the association between leukocyte CoQ10 levels and muscle markers, muscle performance, and reported muscle symptoms. Methods: Symptomatic (n = 35; age 62 ± 7 years) and asymptomatic statin users (n = 34; age 66 ± 7 years) and control subjects (n = 31; age 66 ± 5 years) walked 30, 40, or 50 km/d for 4 consecutive days. Muscle injury markers (lactate dehydrogenase, creatine kinase, myoglobin, cardiac troponin I, and N-terminal pro-brain natriuretic peptide), muscle performance, and reported muscle symptoms were assessed at baseline and after exercise. Leukocyte CoQ10 was measured at baseline. Results: All muscle injury markers were comparable at baseline (P > 0.05) and increased following exercise (P < 0.001), with no differences in the magnitude of exercise-induced elevations among groups (P > 0.05). Muscle pain scores were higher at baseline in symptomatic statin users (P < 0.001) and increased similarly in all groups following exercise (P < 0.001). Muscle relaxation time increased more in symptomatic statin users than in control subjects following exercise (P = 0.035). CoQ10 levels did not differ among symptomatic (2.3 nmol/U; IQR: 1.8-2.9 nmol/U), asymptomatic statin users (2.1 nmol/U; IQR: 1.8-2.5 nmol/U), and control subjects (2.1 nmol/U; IQR: 1.8-2.3 nmol/U; P = 0.20), and did not relate to muscle injury markers, fatigue resistance, or reported muscle symptoms. Conclusions: Statin use and the presence of statin-associated muscle symptoms does not exacerbate exercise-induced muscle injury after moderate exercise. Muscle injury markers were not related to leukocyte CoQ10 levels.