Leisure physical exercise and creatine kinase activity. The Tromsø study

Area of Science:

• Biochemistry
• Exercise Physiology
• Cardiovascular Health

Background:

• Creatine kinase (CK) is crucial for energy metabolism in muscle cells and has implications for cardiovascular risk.
• Skeletal muscle activity, particularly intense exercise, can influence CK concentrations, posing a potential confounder in studies.
• Previous research has primarily linked CK elevations to strenuous sports activities, with less focus on general leisure exercise.

Purpose of the Study:

• To investigate the association between leisure physical exercise and creatine kinase (CK) levels in a general population.
• To quantify the effect of different intensities, frequencies, and durations of physical exercise on CK values.
• To determine if physical activity is an independent predictor of CK levels after adjusting for relevant covariates.

Main Methods:

• The study utilized data from the population-based Tromsø study, including 12,796 men and women.
• Leisure physical exercise was categorized by intensity, frequency, and duration.
• Creatine kinase (CK) levels were measured and analyzed using ANOVA and multivariate logistic regression, stratified by age and sex.

Main Results:

• Creatine kinase (CK) levels significantly increased with higher intensity and frequency of physical exercise in both sexes.
• Heavy exercise (≥2 hours/week) was independently associated with significantly higher CK levels (OR 9.38 in men, OR 5.20 in women).
• Differences in CK between inactive individuals and heavy exercisers were modest (3.1% in women, 6.4% in men) and more pronounced in individuals aged 50 and above.

Conclusions:

• Creatine kinase (CK) is positively and independently associated with increasing levels of leisure physical exercise in the general population.
• While men exhibited approximately twice the CK values compared to women, the overall impact of exercise on CK levels was modest.
• Leisure physical activity is a significant factor influencing creatine kinase concentrations, independent of other health metrics.