Circadian Variations of the Serum Creatine Kinase Level—a Masking Effect?

Abstract

Since the serum level of the enzyme creatine (phospho)kinase (CPK) is frequently used for diagnostic purposes and since circadian variations of this parameter have been observed under different stress conditions, it had to be determined whether they are induced by an endogenous circadian rhythm or whether they are activity-related masking effects. For this purpose, 15 untrained male test persons were examined for a period of 25h each under different conditions: lying constantly in a climatic chamber, everyday activity conditions, resting conditions with intermittent bicycle ergometer tests (1.4 W/kg body weight) between 09:00 and 11:30 or between 15:00 and 17:30. In addition, 5 sportsmen were included in the study under resting conditions and the bicycle ergometer tests in the forenoon. The serum CPK was determined at intervals of 2h or 4h, respectively. Under constant resting conditions, the mean serum CPK level decreased continuously (p < .001, repeated measures analysis of variance [Rep. Mes. ANOVA]), and the final values amounted to approximately 80% of the initial values. In contrast, under everyday conditions, the mean CPK level rose during the activity phase and decreased again to below the initial values during subsequent rest (p < .001, Rep. Mes. ANOVA). In the ergometer tests, the CPK blood level rose in each case after the activity phase and fell again continuously in the following resting period. However, in the calculation of the deviations from the linear trend, it was shown that certain daily variations in the CPK values can be detected under constant resting conditions; however, the amplitude was much smaller than the amplitude under everyday activity conditions. All in all, it can be stated that serum CPK levels are mainly dependent on the physical load conditions, and that the daily changes observed under everyday conditions disappear almost entirely under resting conditions. The daily variation of the serum creatine kinase level under everyday conditions can thus be regarded as a masking effect. These results are of practical significance for diagnosis to the extent that the physical activity that has taken place before the determination of the CPK level must be taken into account in the interpretation of the values. According to the results obtained so far, the CPK serum level may be used in chronobiology as an indicator of masking by physical activity.

Morning-to-evening difference of biomarkers of muscle injury and antioxidant status in young trained soccer players

“…In addition, we found that plasma levels of CK, LDH, ASAT, ALAT, PAL, and GT, known as markers of muscle injury during training and exercise (Nathwani et al 2005;Brancaccio et al 2010), are higher in the evening than in the morning. Similar profile has been observed in the previous reports (Kanabrocki et al 1990;RiveraColl et al 1993;Gutenbrunner 2000). These diurnal variations of leucocytes and muscle enzymes are linked to the circadian rhythm of core temperature (Haus et al 1983;Rivera-Coll et al 1993).…”

“…It is well established that biochemical markers of cellular damage (Kanabrocki et al 1990;Rivera-Coll et al 1993;Gutenbrunner 2000), as well as WBC and their subpopulations (Haus et al 1983), are time-of-day (TOD)-dependent with acrophases generally observed in the evening. The acrophases for the quantities studied coincide with times near those of the oral temperature acrophase (Rivera-Coll et al 1993).…”

Effects of anaerobic exercise and aerobic exercise on biomarkers of oxidative stress

“…Song has already reported no increase in CPK level after an intensive treadmill run to exhaustion (28) thus, CPK level does not necessarily increase after strenuous exercise. CPK decreased after 3 h of exercise: factors that may account for this include resting after exercise and circadian variation (29). Our results are in line with those of a previous study in which it was found that trained subjects, in particular, are unlikely to show increases in CPK levels after exercise and that their CPK levels continuously decrease reaching 60% the following morning (29).…”

Physiological consequences of military high-speed boat transits

“…This period of inactivity would have therefore reduced both of these, and in-turn the clearance rate of the CK (indicating activity) at the 36-h point (Sayers et al 2000). A circadian effect has also been reported for CK (Fuentes-Arderiu and Rivera-Coll 1993) which may have contributed to this reduction, with the trough from the mean 24 h value occurring at about 06:00 h. However, Gutenbrunner (2000) assessed CK circadian variation in relation to physical activity and found that it masked this effect. Therefore, the pattern observed in this research for the CK activity profile with a reduction at 36 h is likely to have resulted from the combination of the circadian effect and the inactivity preceding it.…”