Can a nightmare cause a heart attack?

Just the idea that a nightmare could cause a heart attack might keep people up at night. But horror movie clichés aside, is it possible for a really bad dream to cause a heart attack?

The answer, according to Dr. Robert Aronson, a Sleep Medicine specialist on staff at Advocate South Suburban Hospital in Hazel Crest, Ill., is yes. But the possibility is extremely rare.

“Although no studies have been done to determine just how rare they might be, there have been very few documented cases of people with no apparent health risks having a heart attack after a nightmare,” says Dr. Aronson. “Healthy people’s hearts are usually more than able to handle the stress of even the most frightening dream.”

If someone is at risk for a heart attack because of high blood pressure, diabetes, smoking or other factor, Dr. Aronson says a nightmare could potentially trigger an attack, especially in the morning hours.

“Bad dreams are more commonly seen in the morning hours because the rapid eye movement (REM) phase of sleep, the phase you are most likely to dream, gets longer as the night progresses,” he says. “And, heart attacks are most common in the early morning, when the body clock begins releasing stress hormones and blood pressure usually rises.”

Although nightmares aren’t a primary concern for those with heart disease or risk factors for heart attack, some things can be done to minimize the occurrence of bad dreams and their effects, says Dr. Aronson.

Nightmares, according to the American Psychiatric Society, can be triggered by alcohol, lack of sleep and medications, including some antidepressants and blood pressure medications. Anxiety, depression and sleep apnea, a form of disordered breathing that can disrupt sleep, have also been linked to increased risk of nightmares.

“Although very rare, nightmares can be dangerous to some people with heart attack risk factors,” says Dr. Aronson. “It’s best for them to reduce the risk of nightmares, and further heart damage, by addressing the underlying conditions, such as sleep apnea, alcohol and overall lack of sleep, that cause bad dreams.”

People with sleep apnea and nightmares who are treated with continuous positive airway pressure (CPAP), a treatment that uses mild air pressure to keep the airways open, have marked declines in their nightmares, he adds.

Dr. Aronson also points out that sleep apnea is a much more significant direct risk for heart attacks during sleep compared to nightmares. He says that during an apnea episode, stress hormones and blood pressure surge, increasing heart attack risk in patients with coronary disease. And these apnea-induced changes can increase the risk for stroke.

“Sleep is usually a protected time, with less risk of heart attack per hour than during wake,” Dr. Aronson says. “The opposite is true with sleep apnea, in which the heart attack risk per hour is higher during sleep.”