People with insomnia are 69 percent more likely to have a heart attack compared with those who don’t experience frequent sleep difficulties, according to results from a large new study being presented Monday at the annual meeting of the American College of Cardiology. The analysis also highlights that people who sleep an average of five hours or less per night face the greatest risk of a cardiac crisis.
“Our results have shown that sleep deprivation is associated with a higher risk of heart attacks — the more sleep deprived, the higher the risk we face,” says lead study author Yomna E. Dean, a medical student at Alexandria University in Alexandria, Egypt. “We need to prioritize sleep in our lives to maintain a healthy heart.”
The benefits of a good night’s rest have been well established. Last year, the American Heart Association (AHA) added good sleep to its cardiovascular health checklist. The organization suggests that adults need to get seven to nine hours of sleep every night for optimal cardiovascular health. Better sleep hygiene can help manage health factors including weight, blood pressure, and risk for type 2 diabetes, according to the AHA.
There Is a ‘Just Right’ Amount of Sleep
For this study, which was published recently in the journal Clinical Cardiology, Dean and colleagues analyzed nine previous studies involving more than one million adults from around the globe. Out of this population, about 13 percent were identified as having insomnia, either by medical code or by the presence of any of these symptoms: difficulty falling asleep, difficulty staying asleep or waking early, or not being able to get back to sleep.
Participants were tracked over an average of nine years and had an average age of 52. Around 43 percent were women, and most (96 percent) did not have a prior history of heart attack.
The findings showed that individuals who reported sleeping an average of five or fewer hours per night were 1.38 times more likely to experience a heart attack compared with those who slept six hours a night. Compared with those who slept seven to eight hours, those sleeping five hours or less faced 1.56 times greater odds of having a heart attack.
Chronic Conditions Make Insomnia More Dangerous
Additional risk factors compounded the risk of heart attack associated with poor sleep. “Not surprisingly, people with insomnia who also had high blood pressure, cholesterol [issues], or diabetes had an even higher risk of having a heart attack than those who didn’t,” says Dean. “People with diabetes who also have insomnia had a twofold likelihood of having a heart attack.”
Insomniacs were also more likely to have a heart attack regardless of age, according to the study authors.
Too Much Sleep Is Also Problematic for Your Heart
Too much sleep is also a danger. When comparing those who slept five hours or less and participants who slept nine hours or more, the study team didn’t detect a significant difference in increased heart-attack risk.
“It is important to educate patients about this, as some may assume that if sleep deprivation is harmful to the heart, then excessively long sleep durations could be beneficial. However, that isn’t true,” says Dean.
Insomnia Affects Women More Than Men
Although the researchers said they expected to see a similar incidence of heart attack among men and women, results showed that men with insomnia had a 103 percent higher heart attack risk while women had a 124 percent higher risk.
In general, women are more likely to have insomnia. More than 1 in 4 women in the United States experiences insomnia, compared with fewer than 1 in 5 men, according to the Office on Women’s Health.
Why Is Insomnia Bad for Your Heart?
While this analysis did not look into why insomnia may heighten heart problems, Dean points to evidence indicating that sleep deprivation leads to elevated levels of the stress hormone cortisol, which in turn speeds up atherosclerosis, the buildup of fats, cholesterol, and other substances in the arteries.
“When you are not getting enough restorative sleep, you mess up certain hormones in your body, like cortisol,” says Abha Khandelwal, MD, a cardiologist with Stanford Health Care in California, who was not involved in the study. “It creates a certain type of stress response that can mess up your blood sugar processing, your blood pressure, your risk for abnormal heart rhythms — many things can be impacted. So if you make sure you're getting adequate sleep, that can only help your heart health.”
Dr. Khandelwal notes that this type of analysis is limited, in that findings were gathered from previous studies and information regarding sleep habits was self-reported on questionnaires.
Drugs Aren’t the First Choice for Addressing Insomnia
The research did not consider whether sleep medications might influence heart attack risk. “In general, however, some of the prescription sleep aids are not actually associated with good [cardiovascular] outcomes,” says Khandelwal. “In fact, there’s probably some outcomes showing increased heart disease risk with medications like Ambien (zolpidem), [per research].”
Both Khandelwal and Dean say people wanting to address their insomnia should try behavioral changes first. The Centers for Disease Control and Prevention offers tips, such as going to bed at the same time each night and getting up at the same time each morning, avoiding caffeine or alcohol before bed, and being physically active during the day.
Khandelwal sometimes refers patients to behavioral psychologists to help train them in good sleep habits.
“Those who suffer from insomnia and can’t get enough sleep despite prioritizing proper sleep hygiene should seek medical advice and should be screened for risk factors for heart attack,” says Dean.