Night owls are more likely to suffer from cardiovascular disease, study finds

According to a study published in the "Journal of the American Heart Association", the connection is particularly pronounced in women.

For their study, a team from Brigham and Women's Hospital and Harvard Medical School, both in Boston, analyzed data from more than 300,000 healthy adults between the ages of 39 and 74 who were registered in the UK Biobank - a long-term study from the UK in which various health data is regularly collected from a large sample.

A score was calculated for cardiovascular health, taking into account diet, exercise, sleeping habits and nicotine consumption as well as cholesterol levels, blood sugar and weight.

Almost one in ten is a night owl

Eight percent of the participants described themselves as "definite evening people" with a late bedtime of around 2 a.m. and a late peak of activity during the day. "Definite morning people" made up 24 percent of the sample, with the remainder in between and referred to as a group with a medium chronotype. Chronotype is the technical term for the internal clock or the preferred sleep-wake rhythm.

The research team found that the proportion of those with generally poor cardiovascular health was 79 percent higher among the night owls than in the middle group. In addition, over an observation period of around 14 years, the night owls had a 16 percent higher risk of a heart attack or stroke than people with an average chronotype. The link between late chronotype and poor cardiovascular health was even more pronounced in women than in men.

Night owls often have unhealthy habits

However, it is not the chronotype per se that seems to be decisive for the negative health effect, but rather habits that often go hand in hand with the late rhythm. In "evening people", it is more often the case that the internal clock "may not correspond to the natural day-night light cycle or their typical daily routine", explains study author Sina Kianersi. "Evening people may be more prone to behaviors that can affect cardiovascular health, such as poorer diet, smoking and inadequate or irregular sleep."

The group sees this as good news for night owls, as such habits can be changed. Some therapies and treatment approaches could also be better tailored to the individual with this knowledge.