To dream or not to dream...Riya Khan investigates the effect that dreams have on our well-being and whether they reall are essential for a healthy nights sleep.
Dreams have been a subject of curiosity throughout history with scientists and laymen alike scrambling to interpret their meanings. More recently, the effects of dreams themselves rather than the content of dreams have begun to be explored. In an effort to improve our understanding of sleep, it has been brought to our attention whether dreams are a sign of a healthy night’s sleep.
A healthy night’s sleep doesn’t just involve getting seven to nine hours of uninterrupted sleep but ensuring that you wake up well rested, assuming an absence of sleep disorders. Dreams occur during the rapid eye movement (REM) stage of sleep which constitutes 20-25% of the time spent sleeping, and this is where we experience an increase in breathing rate and eye movement under the eyelids.
Some animal studies have alluded to the function and importance of REM sleep. For example, when rats were deprived of REM sleep for a minimum of four days, they experienced a marked decrease in memory recall. Another study, and perhaps a more well-known one, investigated the effects of total sleep deprivation which also included the REM period. All rats subjected to total sleep deprivation died within 11-32 days or were sacrificed when death was unavoidable. Further studies were carried out using a similar protocol but none could identify the reason for death, or at least anatomical reasons. All rats however did display a debilitated appearance with lesions on their tails and paws and despite an increase in food intake, the animals experienced weight loss, suggesting that lack of sleep can result in adverse health effects and consequently, continue decreasing the quality of sleep.
With regards to REM sleep specifically, researchers at Rutgers University found that the more REM sleep subjects experienced, the weaker their fear response to threatening images displayed as part of the experiment. After getting a good night’s sleep which consisted of a greater percentage of REM sleep, subjects displayed less strong reactions to the same images the next day. This phenomenon is attributed to the activity of a part of the brain known as the amygdala, named as such due to its almond-like shape, which is responsible for secreting norepinephrine and similar stress hormones.
In 60% of cases, nightmares were the result of anxiety or stress during daily life, and this manifested itself through dreaming.
During REM sleep this fear centre of the brain experiences decreased activity, so upon waking, subjects with more REM sleep can be thought to be in a less stressed state of mind, which may contribute to an increase in the quality of that night’s sleep. Alongside a measurable increase in the fear response of the brain, participants in sleep deprivation studies often report feeling irritable, impatient and exhausted following shortened hours of sleep. As REM sleep and dreaming occur more often during the latter stages of sleep, usually in the early mornings, these negative feelings may be linked to the deep REM sleep not being achieved due to shortened sleep times.
It should be noted however that not all dreams are desirable. Nightmares can cause repeated waking throughout the night as well as intense feelings of anxiety and vulnerability, resulting in less restful sleep. In 60% of cases, nightmares were often the result of anxiety or stress during daily life, and this manifested itself through dreaming. Therefore, it can be inferred that good dreams may lead to restful sleep and bad dreams do not, but what exactly causes good dreams is still ambiguous.
Despite some studies suggesting it is still the earliest stages of sleep which carry the most benefit, for example by decreasing the chance to develop neurodegenerative disorders such as Alzheimer’s, REM sleep, and thereby a likely dream-filled sleep, has been shown to provide unique benefits that cannot be attained in other stages of the sleep cycle as mentioned above.
In recent years, people have been sleeping less on average and this REM sleep deprivation can have decimating effects on health. As a result, it is becoming increasingly important to ensure that sleep time is not less than six to seven hours so that sufficient REM sleep (and therefore a dream-filled sleep) can be achieved.
Featured Image: Unsplash / Matheus Vinicius