But the science on this is getting stronger in leaps and bounds.
Thus, in a study just published in PLoS One, Eliane Lucassen and colleagues from the US National Institutes of Health show that “evening types” may indeed have greater health risks.
Based on previous evidence that “evening types” tend to have unhealthier eating habits and suffer from psychological problems more frequently than “morning types”, the authors decided to examine this issue in a cohort of obese individuals reporting sleeping less than 6.5 hours per night.
The study included about 120 individuals with an average BMI of about 40, who slept about 5.8 hours per night.
Not only was progression towards eveningness associated with an increase in BMI, resting heart rate, food portion size, a decrease in the number of eating occasions and lower levels of HDL-cholesterol, evening types also had higher 24 h urinary epinephrine excretion and higher morning plasma ACTH levels.
In addition, Evening types more often had sleep apnea, independent of BMI or neck circumference.
Evidence enough to conclude that preferences to be more active and stay awake in the evenings is not only associated with eating later with a tendency towards fewer and larger meals, it also appears to be a risk factor for sleep apnea and cardio vascular problems – at least in short sleepers.
It seems like taking a good sleep history will soon be part of medical practice – is sleep quality and duration the next vital sign?
Lucassen EA, Zhao X, Rother KI, Mattingly MS, Courville AB, de Jonge L, Csako G, Cizza G, & for the Sleep Extension Study Group (2013). Evening Chronotype Is Associated with Changes in Eating Behavior, More Sleep Apnea, and Increased Stress Hormones in Short Sleeping Obese Individuals. PloS one, 8 (3) PMID: 23483886