Journal Club: Associations between chronotype, morbidity and mortality in the UK Biobank cohort

Alekha Akkapeddi

Article Title: Associations between chronotype, morbidity and mortality in the UK Biobank cohort

Article Link:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6119081/

Authors:  Kristen L. Knutson and Malcolm von Schant

Journal:  Chronobiology International

Type of Research: Cohort study 

Key Takeaways:

1. Sleep disruption and circadian misalignment is associated with cardiometabolic disease risk and subsequently earlier mortality.Chronotype is defined as the estimated part of the day an individual prefers for activities. Later chronotype(evening) and later sleep(a type of circadian misalignment) have typically been associated with adverse health outcomes. This study tested whether a later chronotype is associated with all cause mortality as well as CVD mortality. 

2. The “Definite Evening Type” chronotype was associated with a wide prevalence of diseases such as diabetes, psychological, neurological, respiratory and GI disorders.

3. Evening chronotypes were also associated with all cause mortality.

4. The heritability aspect of chronotype was estimated to be around 21-52%.

Actionable Steps

1. Try to sleep between the hours where the endogenous biological rhythm will be preserved. In other words, try to go to bed between 9-11 PM.

2. Get 20-30 minutes of sunlight in the morning(at sunrise is best) outside to reset circadian rhythm.

3. If it is difficult to fall asleep at night, stay off of devices at least 2 hours before bed and sleep in a cold room. Consider melatonin supplementation if needed.

4. Try to aim for work schedules that support chronotype. If you are a night chronotype, night work may be best suited for you. Conversely, if you are a morning chronotype, a typical work schedule would be best for you.