Written By Shriya Kaza
Dreams are one of the most fascinating aspects of the human sleep cycle. Although there is still much unknown about why we dream and the process itself, research has been conducted to explore the neuroscience and psychology behind this phenomenon. While everyone experiences dreaming, the content within those dreams and their frequency and intensity vary drastically from person to person.
What are dreams?
Dreams are a series of visual images combined with thoughts and feelings that occur during sleep. Some dream in color while others dream in black and white, and those who are blind are likely to have dreams with sound, taste, and smell components. Most people typically spend around 2 hours each night dreaming, although most have difficulty recalling these dreams.
Dreams tend to include emotional and vivid experiences that contain events, themes, concerns, and objects related to the individual's actual life. A combination of these elements create an almost real-life feeling out of seemingly nothing.
Nightmares
Nightmares are a form of dreams that are distressing and bring threatening, scary, or disturbing emotions. People often wake up from their sleep feeling anxious or scared, interfering with their thinking and mood during the daytime. Though these can occur in both adults and children, common causes include: stress, fear, trauma, emotional difficulties, illness, usage of certain medications or drugs, and PTSD. However, it is important to note that bad dreams are often normal and harmless but should be consulted with medical professionals if they start to hinder day to day activities.
Lucid Dreaming
Lucid dreaming is another form of dreaming where the individual is aware that they are dreaming. They have achieved conscious awareness of the dream while still asleep therefore may have some control over the dream. For example, people can make simple manipulations to the dream or make decisions and choices within the dream. These also allow the dream to have heightened emotions such as vibrant colors, exaggerated sensations, and vivid scenes. Some experience lucid dreaming naturally while others actively practice techniques and methods to enhance and experience lucidity. For example, keeping a dream journal, questioning one’s state of reality, and prioritizing quality sleep are just a few methods for those wanting to try lucid dreaming.
What causes dreams?
Although the reason as to why we dream is still largely debated, the most prevailing theory states that dreaming helps people analyze memories and prepares them for situations and challenges that may arise in real life. Other experts similarly theorize that dreams can aid in building memory, processing emotions, mental housekeeping (clearing “erroneous” or unnecessary information), replaying recent events for review/analysis, or simply incidental brain activity (no real purpose or meaning but just a by-product of sleep).
However, scientists and experiments in the neuroscience and psychology fields continue to conduct experiments to fully understand the process of dreaming, but it may be impossible to prove any theory for why people dream despite extensive research.
When do people tend to dream?
To understand when dreaming typically occurs, it is crucial to understand the stages of sleep. These are the phases of the sleep cycle:
Stage 1- Light Sleep (5%): This is the lightest stage of sleep where breathing occurs at a regular rate. There is reduced muscle activity and slow eye movement, lasting around 1-5 minutes.
Stage 2- Deeper Sleep (45%): This is still light sleep but deeper than stage 1. During this stage, brain waves slow down and there are noticeable pauses between short bursts of electrical activity- called sleep spindles. This is said to occur due to the brain organizing memories and information from the time just spent awake.
Stage 3- Deepest Non-REM Sleep (25%): This is the deepest stage of NREM sleep, the older one gets, the less stage 3 sleep they need. At this stage, brain waves are slow but strong. The brain activity’s pattern is known as delta waves therefore this stage can also be referred to as delta sleep or slow-wave sleep (SWS).
Muscle tone, pulse, and breathing rate decrease as the body completely relaxes. At this time, injuries are repaired and immune functions take place. Individuals spend most time in deep sleep during the first half of the night. As they continue sleeping, these stages get shorter and more time is spent in REM sleep.
REM Sleep (25%)- Rapid eye movement (REM) sleep is when most dreams occur. Breathing becomes more rapid, irregular, and shallow and eyes jerk rapidly in various directions. Limb muscles become temporarily paralyzed and heart rate and blood pressure both increase. Due to the increased brain activity, this stage is essential for cognitive functions like memory, learning, and creativity. In fact, during REM sleep, brain activity looks very similar to brain activity when one is awake. During the REM sleep stage, people experience the most vivid, fantastical, and bizarre dreams and include elements of real life. The majority of REM sleep occurs during the second half of the sleep period and increases as the night progresses.
The body cycles through all of these stages around 4-6 times each night, averaging 90 minutes for each cycle.
References
National Institute of Neurological Disorders and Stroke. (2022, September 26). Brain Basics: Understanding Sleep. Www.ninds.nih.gov. https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-understanding-sleep
Nichols, H. (2018, June 28). Dreams: Causes, types, meaning, what they are, and more. Www.medicalnewstoday.com. https://www.medicalnewstoday.com/articles/284378#what-are-dreams
Patel, A. K., Reddy, V., & Araujo, J. F. (2021). Physiology, Sleep Stages. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK526132
PhD, E. M. (2020, January 27). What Happens in the Brain When You’re Dreaming. Elemental. https://elemental.medium.com/what-happens-in-the-brain-when-youre-dreaming-7c0687c38d3
Suni, E. (2020, October 30). Dreams: Why We Dream & How They Affect Sleep. Sleep Foundation. https://www.sleepfoundation.org/dreams
Why Do We Dream? (2022, August 18). Cleveland Clinic. https://health.clevelandclinic.org/why-do-we-dream
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