A recent study published in the Journal of the American Heart Association and relayed by Live Science explains to us that people who go to bed later than average increase their risk of developing cardiovascular disease, which would not be the case for early risers. Even being a night owl would not put you in danger, say researchers who point to other factors.
A person staying up at night is 79% more likely to have a poor cardiovascular health score, on a scale from 0 to 100. This poor score creates a 16% greater risk of stroke or heart attack. Conversely, people who go to bed earlier generally have a “healthier” profile. For scientists, the habits and lifestyles associated with going to bed late or not are the primary culprits.
These scores were calculated using an index taking into account sleep, but also smoking, weight, diet, physical activity, blood sugar, blood pressure and cholesterol. This is the key element: in the 79% of patients presenting a bad score, 75% are linked to lifestyle habits, and primarily smoking. Next comes lack of sleep, then diet and lack of physical activity.
And what about genetics in all this?
The link is simple: night owls generally smoke more than average, sleep less, move less, eat poorly… All these factors combined create this higher risk of heart disease. Living off-beat (whether by choice, by constraint, etc.), also means excluding yourself from the classic schedules of work, school but also leisure and therefore from any social life. This can cause stress which aggravates each factor detailed above.
Genetics must also be taken into account: in night owls, melatonin and cortisol levels will rise later, shifting the natural cycles and rhythm of sleep. All of these disorders can lead to insulin resistance, high cholesterol and even plaque in the arteries. A vicious circle from which it is sometimes difficult to escape.
Our entire social system being organized around a diurnal lifestyle – favoring early risers – it can create a continuous gap in certain people who are unable to sleep at night, a sort of effect jet lag permanent. The difference between men and women also comes into play. Women who stay at night have 96% more heart risks, compared to “only” 67% for men. Today we do not know how to explain such a discrepancy.
While this study demonstrates a clear correlation between these factors, it does not demonstrate a direct causal link. Further larger and more in-depth studies are needed to better understand the impact of delayed sleep.
