Even as an adult, you can learn a lot from fairy tales. Remember Goldilocks? When it comes to heart health, she would have slept "just right." Too little or too much sleep has been linked to heart disease, according to a recent study. What's considered just right? Seven to 9 hours of shut-eye.
In the journal Sleep, researchers reviewed the results of an annual nationwide survey. More than 54,000 adults ages 45 and older were asked about their overall health—specifically, if they had a chronic condition, such as diabetes or coronary heart disease. They also disclosed their average amount of sleep in a 24-hour period.
The survey showed that the majority of adults slept an average of 7 to 9 hours a night. Yet, too many Americans—more than one-third—reported 6 or fewer hours of slumber. An additional 4% said they typically snoozed more than 10 hours.
For those adults who slept too little or too much, researchers found they were more likely to have coronary heart disease, diabetes, or a stroke. They also tended to be obese. Those who slept too much were particularly prone to these heart-related conditions. Why? They may be sleeping longer, but not necessarily better.
When you sleep, your body doesn't simply shut down. It enters a series of sleep stages. During these stages, your body may restore energy, solidify memories, or boost immunity. If one of these stages is cut short, you may miss out on sleep's full rejuvenating potential.
With your heart, the quality of your sleep matters just as much as the quantity, as past research proves. One study found insufficient sleep was tied to high blood pressure, as well as other chronic conditions like asthma and arthritis. In another study, people who suffered from the worst cases of insomnia—a sleep disorder marked by the inability to fall or stay asleep—had a higher chance of having a heart attack.
Inflammation may be central to the sleep and heart connection. When your body reacts to infection, disease, or injury, it releases chemicals that can cause redness and swelling. Experts suspect poor sleep may promote this inflammation, too. It may even lead to atherosclerosis—the buildup of fatty substances along your artery walls. Disrupted sleep may also stifle the production of hormones that regulate energy use and cell repair. Together, these responses may undermine your heart health.
Women may be especially prone to heart problems related to poor sleep. In a recent study, almost 700 men and women with pre-existing heart disease were followed for 5 years. Their sleep quality and inflammation levels were measured at the beginning and end of the study. Women who slept less than 6 hours a night had more inflammation, compared with men who reported the same amount of shut-eye. Hormonal changes during pregnancy and menopause may partly account for women's sleep troubles.
Dreaming of a better night's rest? Click here for some sound sleep tips.