Staying up late one weekend can increase risk of cardiovascular diseases: Japan study

TOKYO — Social jet lag, the delay in the biological clock that occurs when a person stays up late and sleeps in on weekends, can cause arteriosclerosis and increase blood pressure, and such a sleep pattern even on one weekend may increase the risk of cardiovascular diseases, according to recent research.

Heart attacks, strokes and other types of cardiovascular diseases are known more likely to occur on Monday mornings. Kumpei Tanisawa, associate professor of exercise physiology and biochemistry at Waseda University in Tokyo, and other scientists carried out an experiment with 20 men in their 20s and 30s who had fairly consistent sleep patterns on weekdays and weekends. They were divided into two groups: one whose members experienced social jet lag by intentionally delaying their usual bedtime and wake-up time by two to three hours from a Friday night to Monday morning, and another with no delay. The hardness of their arteries and their blood pressure were checked that Monday. The experiment was conducted on the same two groups but with the sleep patterns flipped to rule out other factors.

As a result, the group without social jet lag showed almost no difference in their arteries or blood pressure, while the levels of both artery stiffness and blood pressure rose among those who experienced social jet lag. Specifically, the social jet lag group’s blood pressure rose by roughly 10 mmHg on average.

High blood pressure is said to be the most significant risk factor for lifestyle-related illnesses such as heart diseases. Tanisawa said of the research, “We’ve learned that social jet lag can have an impact even if it’s not chronic and only happens for two days on a weekend. You cannot disregard even one late night.” He added, “It’s best to make sure that social jet lag doesn’t happen, but in reality it’s not easy. We want to figure out how to reduce risks for those who don’t have consistent sleep patterns from the perspectives of kinesiology and nutritional studies.”

The group’s research was published in the Japanese Society of Hypertension’s official journal “Hypertension Research” on July 14.

(Japanese original by Yui Takahashi, Lifestyle, Science & Environment News Department)