For those who eagerly await the weekend to make up for lost sleep during the week, researchers have good news: staying in bed a little longer on Saturdays and Sundays might not be as bad a habit as previously thought.
On the contrary, a moderate amount of extra sleep has been associated with a lower risk of high blood pressure. Researchers have even identified a specific timeframe that seems to bring the most benefits: around an hour and a half more than what we typically sleep during the week.
The conclusions come from a study conducted on approximately 40,000 adults in South Korea, followed for seven years, and presented at the annual congress of the European Society of Cardiology, held in Munich, as reported by The Guardian.
What Does "A Little More" Mean
Researchers calculated the weekend sleep recovery as the difference between the duration of sleep on days off and that during the week.
Overall, individuals who slept more on weekends had about a 6% lower chance of suffering from high blood pressure.
The benefit was slightly more pronounced in sedentary individuals, where the difference reached 6.9%.
The analysis also pinpointed a specific point where the favorable association was strongest: an extra hour and 27 minutes of sleep on weekends. Those who recovered about that much had a 9% lower chance of having hypertension.
However, this doesn't mean that 87 minutes represent a universal "recipe" or that the study proves that extra sleep is the direct cause of reduced risk. The research shows an association between the two.
Why It Might Help
The researchers' explanation is quite simple. When we don't get enough sleep, our bodies are subjected to additional stress, and the heart and blood vessels are put under more strain.
Lack of sleep also hinders the normal drop in blood pressure during the night, which can contribute over time to the development of hypertension.
"If people haven't slept enough during the week, a little extra sleep on weekends may simply be a way for the body to recover from this deficit," explains Dr. Nawon Lee from Korea University in Seoul, the study's author.
The conclusion is significant. Globally, over 1.3 billion people suffer from hypertension, a condition that significantly increases the risk of heart attack, stroke, kidney disease, and premature death.
But Not Until Noon
There is, however, a limit. More sleep doesn't automatically mean more protection. Individuals who slept over four hours more on weekends actually had a higher risk of hypertension.
The explanation might lie in disrupting the biological clock. If the difference between the weekday and weekend schedules becomes too large, the circadian rhythm is disturbed, and any potential benefits of catching up on sleep may be nullified.
"Moderate weekend recovery sleep can have a protective effect," says Lee. When it becomes excessive, however, irregularities in the sleep schedule and disruption of the circadian rhythm increase.
In other words, researchers don't recommend sleeping as much as possible on days off. A regular bedtime and wake-up routine remain the ideal choice. But for those who have accumulated a sleep deficit after a busy week, an extra hour or two on weekends could be more helpful than a reason for guilt.
Doesn't Replace Exercise
However, the results don't turn weekend sleep into a shortcut to a healthy heart.
Dr. Sonya Babu-Narayan, a cardiologist and clinical director of the British Heart Foundation who was not involved in the research, emphasizes that exercise, maintaining a healthy weight, and balanced nutrition remain essential for preventing hypertension.
The study "is not a green light for physical activity to take a back seat," she says.
There is, however, a reassuring message for those who, after five early mornings with the alarm clock, catch up on sleep over the weekend: it's not necessarily laziness, and there's no need to feel guilty about it. Sometimes, the body is simply trying to make up for what it missed during the week.
G.P.