Sleep for many of us can be a reward, an escape, or a dread, and each of them has been studied by researchers attempting to tease out the disturbing parts. With the thought in mind, over the past several decades, the specialization of Sleep Medicine has become increasingly important as it relates to our daily lives and our bodies' functioning. But sleep also, according to some recent work, may carry with it a high price in terms of physiological aging.
One question that has always remained in the minds of both professionals and the public is whether or not one aspect of sleep, nightmares, should be interpreted as a psychological part of our life or a biological phenomenon. We may not have the answers to everything, but we may be coming closer to understanding the reason people may have nightmares, and it may not be unconscious conflict.
Any situation that poses a danger to one's life, safety, or bodily integrity is considered a nightmare according to the diagnostic guidelines (ICSD-3, DSM-5, ICD-10). But there is a lack of research examining nightmare content in large samples.
Findings from an analysis of 253 nightmares and 431 bad dreams recorded in daily logs deviated from the usual themes; themes such as physical aggression, interpersonal conflicts, feelings of failure and helplessness, health-related worries, and death topped the list, while dreams about falling and being chased were less common.
Another study detected a clear gender difference; while no impacts were identified for paralysis, falling dreams, or close individuals disappearing or dying, more females tended to describe these topics. Based on our understanding of the causes of nightmares, the topics addressed can include threats to physical safety and existence, the disappearance or death of loved ones, tense relationships, and even feelings of failure. So, it would seem, that things that may be happening in our relationship during the day move over into our dream world to concoct stories with this content.
Research has indicated that there may be a relationship between childhood distressing dreams and later cognitive decline. For some, this may mean a subtle change in one portion of a gene, the telomeres, that shorten and result in the number of physical changes, possibly aging. One of the changes appears to be an increasing likelihood of developing Parkinson's disease. The reason this may be a preceding sleep activity and PD is unknown at this time. But there are many other disorders that may also be associated with nightmares for a variety of reasons, and once again, we do not have the definitive answer here.
Heart disease, high blood pressure, diabetes, chronic obstructive pulmonary disease (COPD), arthritis, and worse self-reported health are among age-related illnesses that have been associated with disturbing nightmares. It would not be unreasonable to delve into the biological and psychological reasons these disorders may be associated with nightmares, such as pain syndrome, inability to breathe adequately during sleep, and disturbances from high blood sugar, which are only a few of the possible causes.
Those being treated with certain medications, such as steroids, in cancer treatments may also experience an increase in nightmares. We know that steroids affect mood, and this can, possibly, be a reason for this sleep activity.
Regarding aging, there are at least two interesting research studies of note. One study that followed 3,113 people for nearly two decades found that the risk of premature mortality was three times greater for those who experienced nightmares at least once a week compared to those who experienced them less frequently.
Out of 71,857 participants in a U.K. Biobank cohort, 51 died before their expected time during the study's two-year duration. After accounting for confounding variables, the finding was still shocking: the risk was nearly three times higher for those who had nightmares at least once a week compared to those who had them less frequently.
The conclusion that one sleep researcher came to was that we need to delve deeper into the association between sped-up aging and nightmares to determine what might be the best treatment. In other words, should we treat nightmares per se to prevent this accelerated aging? But do we really know the genesis of nightmares adequately, and is that where the research needs to go to come to some reasonable expectation of promoting healthy aging?