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Updated: Jun 2, 2026
Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
Role of patient chronotype on circadian pattern of myocardial infarction: a pilot study
Yavuz Selvi1, Michael H Smolensky, Murat Boysan
1Department of Psychiatry, Faculty of Medicine, Yuzuncu Yil University, Van, Turkey. dryavuzselvi@yahoo.com
Insights
Chronotype, or an individual's natural sleep-wake cycle, influences the timing of acute myocardial infarction (AMI) onset. Morning-type individuals experience peak AMI risk earlier in the day compared to evening-type individuals.
Area of Science:
- Cardiology
- Chronobiology
- Sleep Medicine
Background:
- Population studies show acute myocardial infarction (AMI) risk is highest in the morning.
- Chronotype, characterized by morningness or eveningness, describes individual differences in circadian rhythms.
Purpose of the Study:
- To investigate the impact of chronotype on the timing of AMI onset.
- To explore whether morning or evening chronotypes influence the clock hour of AMI occurrence.
Main Methods:
- A pilot study classified 63 morning- and 40 evening-type patients using the Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) post-AMI.
- Analyzed wake-up and bed times, and the time lag between waking and AMI onset.
- Examined the 24-hour pattern of AMI onset in relation to chronotype.
Main Results:
- Morning-type individuals had average wake-up times approximately 2 hours earlier than evening-type individuals.
- The time lag between waking and AMI onset did not differ significantly between chronotypes.
- The peak occurrence of AMI was observed between 06:01–12:00 h for morning types and 12:01–18:00 h for evening types.
Conclusions:
- Chronotype appears to influence the clock time of AMI onset.
- Larger studies are needed to confirm the role of chronotype in AMI timing, including individuals with intermediate chronotypes.
Abstract:
Population-based studies indicate the risk of acute myocardial infarction (AMI) is greatest in the morning, during the initial hours of diurnal activity. The aim of this pilot study was to determine whether chronotype, i.e., morningness and eveningness, impacts AMI onset time. The sample comprised 63 morning- and 40 evening-type patients who were classified by the Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) in the hospital after experiencing the AMI. The average wake-up and bed times of morning types were ~2 h earlier than evening types. Although the lag in time between waking up from nighttime sleep and AMI onset during the day did not differ between the two chronotypes, the actual clock-hour time of the peak in the 24-h AMI pattern did. The peak in AMI of morning types occurred between 06:01 and 12:00 h and that of the evening types between 12:01 and 18:00 h. Although the results of this small sample pilot study suggest one's chronotype influences the clock time of AMI onset, larger scale studies, which also include assessment of 24-h patterning of events in neither types, must be conducted before concluding the potential influence of chronotype on the timing of AMI onset.
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