Ask Well: Can Nightmares Cause a Heart Attack?
Q: Can nightmares or upsetting dreams cause a heart attack while sleeping?
A: There are case reports of people with no previously known risks having a heart attack after a nightmare, though they appear to be quite rare.
No studies have been done to determine just how rare nightmare-induced heart attacks might be, and experts do not know whether they may result from the pulse-racing effects of the frightening dream itself.
Nightmares are more commonly seen in the rapid eye movement, or REM, phase of sleep, which gets longer as the night progresses. Therefore, nightmares are more likely to occur in the early morning hours.
Heart attacks, too, are most common in the early morning hours, when internal body clocks start secreting stress hormones and blood pressure tends to rise, said Dr. Mary Ann McLaughlin, a cardiologist at the Icahn School of Medicine at Mount Sinai in New York. If someone is at risk for a heart attack — because of high blood pressure, diabetes, sleep apnea, smoking or other factors — that attack is more likely to occur in the early morning.
But “it’s rare for an otherwise healthy person to have a nightmare that causes a heart attack,” said Dr. McLaughlin.
Nightmares can be triggered by alcohol, lack of sleep and medications, including some antidepressants and blood pressure medications, she said. Anxiety and depression have also been linked to increased risk of nightmares.
On the flip side, patients with heart disease often have sleep apnea, a form of disordered breathing that can lead to fragmented sleep, and potentially more nightmares, said Dr. Neomi Shah, a sleep specialist, also at Mount Sinai.
One 2013 study found that apnea patients with regular nightmares woke up more often than those who didn’t. Nightmares disappeared in more than 90 percent of the patients who used a continuous positive airway pressure, or CPAP, machine to treat their apnea.
The bottom line: Nightmares are potentially life-threatening, though this appears to be very rare. And there are ways to reduce risks of both nightmares, by addressing underlying conditions like sleep apnea, alcohol use and lack of sleep, as well as heart disease.