Just three nights without a full 8 hours of sleep can harm your heart

Independent

13-05-2025

Think only a few hours of sleep is enough? Think again.
Swedish researchers say just three consecutive nights without a full eight hours of sleep can harm a person's heart health.
'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,' Dr. Jonathan Cedernaes, a docent at Uppsala University, said in a statement.
Cedernaes led the study, which was published recently in the journal Biomarker Research.
To reach these conclusions, the authors examined how sleep deprivation affects the body's biomarkers, which are indicative of a person's overall health.
Their research included 16 young men who had healthy sleep habits. The men spent two sessions in a sleep laboratory, with controlled meals and activity levels. During one session, they got 8.5 hours of sleep for three consecutive nights. For the second, they only got about four hours.
The researchers collected blood samples from the participants during the morning and evening, as well as following high-intensity exercise lasting 30 minutes.
They measured the levels of 90 proteins in the blood, finding that many associated with increased inflammation rose when the men were sleep-deprived. Many of these proteins have already been linked to an increased risk of cardiovascular disease.
Further research needs to be conducted, they noted, to understand how the same effects might differ in women, older people, people with heart disease, and those with different sleep patterns. However, previous research has linked a chronic lack of sleep to an increased risk of heart attack and stroke. The recommended amount of sleep for adults is at least 7 hours each day. In the U.S., 12 percent of residents say they have been diagnosed with chronic insomnia.
'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,' Cedernaes explained. 'This means that it's important to emphasise the importance of sleep for cardiovascular health even early in life.'
Exercising led to a slightly different response, the study authors said. However, a number of key proteins increased whether the person was sleep-deprived or not.
'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,' said Cedernaes.