That doesn’t mean nightmares are nothing to worry about, however. Recent research has found a connection between troublesome dreams and major underlying health problems. Read on to find out what your bad dreams could be signaling. READ THIS NEXT: If You Sleep This Way, Your Dementia Risk Soars, Study Warns. Researchers at the University of Birmingham in the U.K. recently discovered a concerning link between nightmares and Parkinson’s disease. In a June 2022 study published in eClinicalMedicine, the researchers used data from the U.S. that spanned 12 years and analyzed 3,818 older men living independently. Of these, there were 91 diagnosed cases of Parkinson’s disease by the end of the study.ae0fcc31ae342fd3a1346ebb1f342fcb According to the researchers, participants who experienced frequent bad dreams were twice as likely to develop Parkinson’s than those who did not. Those who had an increase in nightmares during the first five years of the study were more than three times as likely to develop the disease, “which suggests that frequent distressing dreams may be a prodromal symptom of [Parkinson’s disease],” the study stated. Parkinson’s is not the only brain disorder potentially linked to bad dreams, however. A follow-up study from the same researchers, published Oct. 2022 in eClinicalMedicine, found a link between nightmares and dementia. That study looked at data from over 600 people in the U.S. between the ages 35 to 64 and 2,600 people age 79 and older. “I found that middle-aged participants who experienced nightmares every week were four times more likely to experience cognitive decline (a precursor to dementia) over the following decade, while the older participants were twice as likely to be diagnosed with dementia,” study author Abidemi Otaiku wrote in an article for Science Alert. “Overall, these results suggest frequent nightmares may be one of the earliest signs of dementia, which can precede the development of memory and thinking problems by several years or even decades—especially in men.” For more health advice delivered straight to your inbox, sign up for our daily newsletter. Earlier research has shown that bad dreams could be related to more than just your brain. During the annual meeting of the Associated Professional Sleep Societies in 2020, researchers presented a new study linking nightmares to heart disease, Medscape Medical News reported. The study looked at 3,468 veterans who served one or two tours since Sept. 11, 2001. Of these, roughly 31 percent reported having frequent nightmares, and 35 percent reported experiencing moderately distressing nightmares over the previous week. Even after adjusting the results for age, race, sex, depression, and post-traumatic stress disorder (PTSD), the researchers still found that frequent nightmares were significantly associated with hypertension and heart problems. “A diagnosis of PTSD incorporates sleep disturbance as a symptom. Thus, we were surprised to find that nightmares continued to be associated with [cardiovascular disease] after controlling not only for PTSD and demographic factors, but also… depression diagnosis,” Christi Ulmer, PhD, assistant professor in the Department of Psychiatry and Behavioral Sciences atDuke University Medical Center, told Medscape Medical News. Isabella Gordan, a sleep expert and the founder of Sleep Society, further breaks down the link between nightmares and health problems: “The connection between nightmares and dementia has been linked to the breakdown of cognitive areas affected by dementia, such as memory and processing speed. Nightmares may also be an early warning sign in some cases of Parkinson’s disease due to a decrease in dopamine production or an increase in REM sleep behavior disorder,” Gordan tells Best Life. “As for heart disease, studies have found that frequent nightmares can lead to higher levels of cortisol (a stress hormone) being released during the night, which could cause increased blood pressure, raising one’s risk for developing heart disease.” Of course, bad dreams aren’t always a sign of a bigger problem. According to Gordan, people may experience troublesome dreams regularly without underlying health issues, as dreams are a “normal part of the sleep cycle and often reflect our current mental state or worries during the day.” This means anything from “stressful situations, intense emotions, and even certain medications” can affect what we dream about, she says. But that doesn’t mean it’s a bad idea to look into your nightmares, just to be safe. “People should talk to their doctor if they are regularly having bad dreams or have started experiencing an increase in the number of bad dreams they’re having,” Gordon says. “Research has suggested that frequent nightmares and bad dreams can be a sign of deteriorating mental and physical health, including conditions such as dementia and Parkinson’s disease, so it’s important to speak to a healthcare provider.”