Adequate sleep and rest are crucial for long-term heart recovery after a heart attack!

This conclusion comes from a new study involving mice and humans. The research indicates that after a heart attack, immune cells flood the brain to promote deep sleep.

This deep sleep can alleviate heart inflammation and help repair the damaged heart.

The findings have been published in the journal Nature.

Sleep and Heart Disease in Mice

In recent years, there has been growing recognition that sleep is an essential factor in maintaining heart health. Scientists have long known the link between sleep and cardiovascular health. For example, studies have shown that sleep can improve blood pressure, reduce cholesterol levels, and that people with poor sleep are at a higher risk of hypertension compared to those who sleep well.

However, the role of sleep deprivation in increasing the risk of heart disease has remained unclear, and there has been limited research on how cardiovascular disease affects sleep.

In the new study, researchers conducted experiments on mice. They induced heart attacks in the mice and monitored their brainwaves. They found that these mice spent significantly more time in slow-wave sleep (a deep sleep stage associated with recovery) compared to mice that did not experience a heart attack.

The researchers sought to understand what caused this effect. After a heart attack, immune cells trigger widespread inflammation in the heart. The researchers wondered if similar immune changes occurred in the brain. They discovered that after a heart attack in a mouse, immune cells called monocytes flooded its brain. These cells produce large amounts of a protein called tumor necrosis factor (TNF), an essential inflammatory regulator that can promote sleep.

To confirm that these cells were indeed linked to increased sleep, the researchers blocked the accumulation of monocytes in the brains of these mice. They found that when they did so, the mice that had experienced heart attacks no longer showed increased slow-wave sleep. This suggests that the influx of monocytes into the brain contributes to the post-heart attack sleep boost. Similar experiments confirmed the role of TNF as a messenger in brain cells inducing sleep.

To explore the role of this increased sleep, the researchers repeatedly disrupted slow-wave sleep in mice with heart disease. They found that doing so led to more inflammation in both the brain and the heart. Mice that were allowed to sleep undisturbed after a heart attack had significantly better recovery outcomes compared to those whose sleep was disrupted. In other words, adequate sleep is essential for the recovery of mice that have experienced heart attacks.

Similar Effects May Occur in Humans

Researchers also analyzed human data samples from another sleep restriction study and found that sleep likely plays a similar role in humans. In that study, researchers sought to determine whether sleep deprivation could be a contributing factor to heart disease. They asked healthy volunteers, who had no history of heart disease, to reduce their sleep by 90 minutes per night for six weeks. The goal was to measure the long-term effects of sleep deprivation on human health.

The initial findings from that study showed that insufficient sleep caused physiological changes that increased the risk of heart disease. In the new research, when the team analyzed blood samples from the sleep restriction study participants, they identified similar mobile inflammatory cells. This suggests that the mechanisms observed in sleep-deprived mice after heart attacks could also occur in sleep-deprived humans.

Researchers further examined individuals with acute coronary syndrome, a condition that includes heart attacks and is caused by a sudden reduction in blood flow to the heart muscle. They found that, compared to those with good sleep, individuals with poor sleep quality in the weeks following such an event had a higher risk of heart attacks and other severe cardiovascular complications over the next two years.

These findings highlight the importance of good sleep after a heart attack and emphasize the bidirectional relationship between sleep and the immune system. Following a heart attack, treatments typically focus on dietary changes, increased physical activity, and weight loss. However, based on these new findings, recommending improved sleep as part of the recovery plan for cardiovascular patients appears essential.