A chronotype is a designation for individual preference of times for different activities in humans. In chronobiological research, it can be measured in many ways, including subjective questionnaires. The most frequently used questionnaires for determining the chronotype are Morningness-Eveningness Questionnaire (MEQ) and Munich Chronotype Questionnaire (MCTQ). Many studies from around the world have already reported metric properties of the MEQ and MCTQ and their relationship in different languages. In this study, we created the Czech version of the MCTQ and examined its relationship with the Czech version of MEQ, including socio-demographic effects. We also examined the ability of the MCTQ to identify chronotypes and cutoffs for their determination. In total, 2703 people (1964 females, 739 males, 18-75 years of age) were screened by the MEQ, MCTQ and reported on age, sex and self-declared body mass index (BMI). We found a significant relationship (p < .001) between MEQ and MCTQ (MSFsc score, used as a chronotype indicator). No significant sex differences in MEQ and in MSFsc were found, but the relationship between age and MSFsc (mid-sleep on free days corrected for sleep debt on weekdays) (p < .001), MEQ (p < .001), social jet-lag (SJL, p < .001) and BMI (p < .001) were found. The SJL was related to MSFsc (p < .001), MEQ (p < .001) and BMI (p < .05). The optimal cutoff value of MSFsc to identify morning and evening chronotype was 3.35 and 4.6, respectively. The results of this study support the mutual substitutability of the Czech version of MEQ and MCTQ.
Keywords: Chronotype; MCTQ; MEQ; chronotyping; questionnaire; validation.