Sleeping in on weekends is good for the heart: What research has shown

Sleeping an extra hour or two on the weekends can reduce the risk of high blood pressure, a study shows.

Scientists have largely asserted that people should keep regular bedtimes and wake-up times, maintaining a consistent sleep schedule across the week, including weekends.

But the new study questions that view, building on other recent research that suggests weekend lie-ins, and extra sleep more broadly, are good for the heart and overall health.

What does the latest study say?

The findings, presented on Sunday at the European Society of Cardiology’s annual congress in Munich, Germany, were based on a seven‑year study of 40,727 adults in South Korea. These were adults from the Korea National Health and Nutrition Examination Survey, studied from 2016 to 2023.

The researchers examined how many extra hours participants slept at weekends compared with weekdays.

The latest study found that catching up on sleep at the weekend after a long workweek lowers the prevalence of high blood pressure.

In all, weekend catch-up sleep was associated with a 6 percent decrease in the chances of high blood pressure. This decrease was larger for physically inactive people, who saw a 6.9 percent decrease in chances of hypertension. The study found that someone getting one hour and 37 minutes of extra sleep at weekends could reduce their chances of hypertension by 9 percent.

“Blood pressure normally decreases during sleep. When people consistently do not get enough sleep, that normal overnight reduction can be impaired,” Christopher Depner, assistant professor at the Department of Health and Kinesiology at the University of Utah, told Al Jazeera.

“Insufficient sleep can also negatively affect stress hormones and inflammation. Over time, these changes may contribute to higher blood pressure and cardiovascular risk. Getting adequate sleep may therefore prevent these adverse cardiovascular risks.”

But Depner, who was not associated with the study, pointed out that the findings have not yet been published in a peer-reviewed journal.

The findings also show that the extra weekend sleep only worked when lie-ins were kept at a moderate length – about one to two hours of extra sleep with an optimal increase of about one hour and 37 minutes.

“Large shifts in sleep timing between weekdays and weekends can shift circadian timing—sometimes referred to as ‘social jet lag’ —and have been associated with adverse metabolic and cardiovascular outcomes including risk of diabetes,” Depner said.

As of 2024, 1.4 billion adults aged 30-79 worldwide have hypertension, accounting for 33 percent of the world population in this age range, according to the World Health Organization. High blood pressure is a major cause of premature death worldwide, the United Nations agency added.

Do other studies support similar claims?

In the 2024 European Society of Cardiology’s annual congress in London, researchers presented a study of more than 90,000 individuals.

The study found that people with the most weekend catch-up sleep had about a 20-percent lower risk of developing heart disease than those with the least.

A large body of modern medical research supports a strong association between adequate sleep and better heart health.

What does the broader science say about sleep?

For decades, the medical consensus has been that too little sleep can harm cardiovascular health, that seven to nine hours a night is generally optimal for adults, and regularly sleeping much more than that may sometimes point to an underlying health problem.

However, scientists have previously suggested that weekend lie-ins could be harmful by disrupting the body’s natural circadian rhythm, a built-in biological clock running on an approximately 24-hour cycle that regulates sleep, hormone release and body temperature.

In 2019, researchers studied 36 adults, dividing them into three groups. One group had their sleep restricted to five hours a night over nine nights, including weekends; another was restricted to five hours a night but was allowed to catch up unrestricted at weekends; and one group was allowed nine hours of sleep over nine nights.

Both the groups with restricted sleep snacked more in the evening and saw a decline in metabolic health. The study found that the people who slept more at the weekend partly improved while they were actually sleeping more.

However, once they went back to short sleep, the benefits disappeared and overall metabolic health was still worse than in people who consistently slept more every night.

Should the new findings be treated with caution?

Yes, suggests Depner, because the findings only support a correlation between extra weekend sleep and benefits to the heart — not a causal link.

“I would not recommend changing public-health advice based on this study. Observational studies cannot establish that sleeping longer on weekends causes the lower risk,” he said. “People who obtain more weekend sleep may differ in many other ways from people who do not, leading to residual confounding, meaning other factors are contributing to the findings beyond weekend recovery sleep.”

Depner also emphasised the need to keep extra sleep to moderate levels.

“For someone who has not obtained enough sleep during the week, a modest amount of additional weekend sleep may provide some recovery while producing relatively little disruption of sleep timing,” he said. “Very large differences between weekday and weekend sleep, however, can shift circadian timing and make the transition back to the weekday schedule more difficult on Monday morning.”