Even if you're in great shape, skipping sleep for just a few nights could raise your risk of heart attack or stroke, according to new research from Sweden.
A team at Uppsala University found that even short-term sleep loss can trigger changes in the body that are linked to heart disease. And it doesn't take much — just a couple of nights of poor sleep can set those changes in motion.
Dr. Jonathan Cedernaes, who led the study, explained, "Unfortunately, nearly half of all Swedes regularly experience disturbed sleep, and this is particularly common among shift workers. That is why we wanted to try to identify mechanisms that affect how lack of sleep can increase the risk of cardiovascular disease. Ultimately, the purpose was to identify opportunities to address these problems."
Sleep issues are a growing concern worldwide. Large studies have already shown that people who don't sleep well are more likely to suffer from heart attacks, strokes, and irregular heartbeats.
To dig deeper, Dr. Cedernaes and his team studied how poor sleep affects certain proteins in the blood that are linked to heart disease. The study involved 16 healthy young men with normal body weight and no sleep issues.
They stayed in a sleep lab under carefully controlled conditions — meals, movement, and even activity levels were all monitored. In one part of the study, the men slept for 8.5 hours each night for three nights. In the other, they only got about 4 hours of sleep per night.
Blood tests revealed that sleep-deprived participants showed signs of increased inflammation and changes in nearly 90 proteins — even though they were, as the researchers put it, "previously perfectly healthy."
The researchers wrote, "Our findings based on highly standardised in-lab conditions, indicate that even short-term sleep restriction can produce a biomarker profile associated with increased cardiovascular disease risk."
Many of the proteins they identified have already been linked to heart problems like heart failure and coronary artery disease.
Just Three Bad Nights Of Sleep Can Harm Your Heart, Study Finds Dr. Cedernaes added, "Many of the larger studies that have been done on the link between sleep deprivation and the risk of cardiovascular diseases have generally focused on slightly older individuals who already have an increased risk of such diseases. That is why it was interesting that the levels of these proteins increased in the same way in younger and previously perfectly healthy individuals after only a few nights of sleep deprivation. This means that it's important to emphasise the importance of sleep for cardiovascular health, even early in life."
The researchers also looked at how sleep loss might affect the benefits of exercise. Some positive changes from physical activity still occurred — even with sleep deprivation — but others didn't.
They've previously found that exercising on little sleep can put extra strain on the heart's muscle cells. Still, Dr. Cedernaes pointed out, "With this study, we have improved our understanding of what role the amount of sleep we get plays in cardiovascular health. It's important to point out that studies have also shown that physical exercise can offset at least some of the negative effects that poor sleep can cause. But it's also important to note that exercise cannot replace the essential functions of sleep."
He also noted that more research is needed: "Further research is needed to investigate how these effects might differ in women, older individuals, patients with heart disease, or those with different sleep patterns. Our ongoing research will hopefully help to develop better guidelines on how sleep, exercise and other lifestyle factors can be harnessed to better prevent cardiovascular diseases."
