Health/Sci-TechLifestyleVOLUME 19 ISSUE # 6

Night owls almost twice as likely to have clogged arteries as early risers, study suggests

Night owls may have almost twice the risk of hardened arteries compared to early birds. Hardened arteries, caused by a build-up of fatty deposits in the blood vessels, are more common in older people with high blood pressure and cholesterol, and increase the risk of having a heart attack or stroke.

Researchers looked at 771 people, aged 50 to 64, to see if the condition was more common in night owls, who tend to wake up and go to bed later and are more energetic in the afternoon and evening. They found people who said they were definite night owls were 90 per cent more likely to have hardened arteries than those who were definite early birds.

Around 17 per cent of people say they are definite night owls, with this category excluding people who say they are night owls ‘to some degree’. Evidence suggests that being a night owl, rather than being particularly active during daylight hours, as humans evolved to be, may work against our natural body clock.

This mismatch in timings has been linked to high blood pressure and inflammation, which can damage the arteries and cause them to harden. The fatty deposits causing the hardness can then rupture, causing blood clots which lead to heart attacks and strokes. However night owls also tend to have more unhealthy lifestyles, like eating poorly, which could also raise their risk of hardened arteries.

Mio Kobayashi Frisk, who led the study from the University of Gothenburg in Sweden, said: ‘People who are night owls should be conscious of the potential link with hardened arteries, and maybe try not to go to bed too late when they are tired. ‘As they are possibly in a risk group for cardiovascular disease, they might want to consider a lifestyle like eating healthily and getting enough sleep and exercise.’ The study, published in the journal Sleep Medicine, looked at people asked in previous research if they were a ‘distinct’ morning or evening person, a morning or evening person to ‘a certain degree’ or neither.

Hardened arteries were seen in around 22 per cent of definite early birds, but almost 41 per cent of definite night owls. Those who said they were a definite evening person were 90 per cent more likely than a definite morning person to have hardened arteries after taking into account other factors including their weight, physical activity and alcohol consumption. Researchers then looked at people’s risk of developing cardiovascular disease in the next decade, which is worked out based on their age, sex, blood pressure, level of ‘bad’ cholesterol and smoking status.

Definite night owls with a high risk of cardiovascular disease were 15 times more likely to have hardened arteries than other people with a low risk of cardiovascular disease.