morningness

Morningness, also known as a morning chronotype or morning preference, describes a tendency to favor earlier sleep and wake times and to perform best in the morning. It is part of the broader concept of chronotype, which also includes eveningness, and exists along a spectrum rather than as a simple yes/no category.

Biologically, morningness relates to an earlier circadian phase. The body’s internal clock in the suprachiasmatic nucleus regulates rhythms such as melatonin production and core body temperature. Early chronotypes typically show earlier dim light melatonin onset and earlier wake times, aligning activity with daytime.

Assessment typically relies on questionnaires and objective measures. The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) is a common self-report instrument. The Munich Chronotype Questionnaire (MCTQ) and actigraphy provide complementary or objective estimates of chronotype and sleep schedules, reinforcing the view of morningness as a continuum across individuals.

Age and developmental factors influence chronotype. Morning preference tends to be stronger in children and older adults, while adolescence and young adulthood are associated with greater eveningness. Genetic contributions are evident, with heritability estimates indicating a substantial genetic component; specific clock-gene variants have been linked to chronotype, though environmental and lifestyle factors also play important roles.

Implications include how chronotype interacts with sleep health and daily functioning. Morning types often experience better alignment with typical work or school schedules and lower social jetlag, whereas evening types may face greater mismatch and sleep debt when early starts are required. Light exposure, social demands, and work arrangements can modify effective timing, and interventions such as morning bright light exposure can help advance circadian phase for late chronotypes.