A lack of sleep can make you gain weight because it can:

• Cause the increases your ghrelin, which is a hunger-arousing hormone.

• Cause the decrease of leptin, a hunger-suppressing hormone.

• Increase the production of cortisol, which is a stress hormone that stimulates the body to make fat.

• Enhance limbic brain responses to the mere sight of food and decrease cortical responses that help us resist temptation.

Children and adults who sleep less on average are usually heavier than those who get a lot/the appropriate amount of sleep.

• Our brain finds fattier foods more appealing in times of sleep deprivation.

• Therefore, sleep deprivation can explain sudden weight gain in students.

Sleep helps boost our immune system, so when we have a lack of sleep, our immune system is weaker — therefore, we are more susceptible to disease.

• The reason we sleep a lot when we are sick/battling an infection is because our immune system gets stronger, which in turn helps fight off the infection.

• Those who averaged 5 hours of sleep were 4.5 times more likely to catch a cold than those who slept 7 hours a night.

Sleep deprivation can slow down reaction time and increase errors regarding visual attention tasks.

• A slower reaction time can lead to operational error and even car crashes.

• The spring-forward time change has led to an increase in vehicular accidents, as a result of “shortened sleep.”

People who are more tired than normal are known as “cyberloaf,” which is when you spend an excessive amount of time online/on the internet.

Different sleep disorders include:

• Insomnia: recurring problems in falling asleep.

  • Can result in excessive tiredness and depression.

  • Sleeping pills aren’t a great treatment for insomnia, as they reduce REM sleep and make you build up a tolerance, which means you will always need increasing doses.

• Narcolepsy: a sleep disorder characterized by uncontrollable sleeping/sleep attacks; the person may fall right into REM sleep, often at inappropriate times.

  • It usually lasts 5 minutes or less.

  • It can be triggered by intense emotions, such as shouting angrily, laughing loudly, etc.

  • There are treatments, but they do not prevent the disorder a great deal.

• Sleep apnea: a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.

  • After a minute or so without breathing during sleep, decreased oxygen in their blood will cause people with the condition to snort in the air and wake up.

  • May cause fatigue and depression

  • A common treatment is to sleep with a mask device that keeps the airway open when sleeping.

• Night terrors are a sleep disorder characterized by high arousal and the appearance of being terrified.

  • Different than nightmares because they occur during NREM-3 sleep, happen within two-three hours of falling asleep, and are rarely remembered.

• Sleepwalking and sleeptalking are usually childhood sleep disorders that are known to run in a family’s lineage.

  • Sleepwalking is when someone gets up out of bed in the middle of sleep and starts to walk around and act out certain things while still asleep.

    • Happens during NREM-3 sleep

  • Sleeptalking is when someone speaks, usually gibberish and nonsensical language, while they are still asleep.

    • Occurs in NREM-3 sleep, also

Dreams are a sequence of images, emotions, and thoughts passing through a sleeping person’s mind.

• Unlike daydreams, REM dreams are very vivid, emotional, and often bizarre.

After suffering a trauma, people commonly have nightmares, which the mind has to help extinguish daytime fears.

Blind people have reportedly dreamed of their other senses rather than sight—they use their nonvisual senses.

Those who consume violent media are more likely to have violent dreams; those who consume sexual media have sexual dreams.

A particular stimulus—such as an odor sound—may be woven into the dream immediately and ingeniously.

• For example, if someone is sprayed with cold water when they are dreaming, they are more likely to dream about something like a waterfall right after.

While we are sleeping, we cannot remember recorded information when we are asleep, but we can learn to associate a sound with a pleasant or unpleasant odor.

Wish-fulfilment theory: Sigmund Freud’s proposition that dreams provide a psychic safety valve that discharges otherwise “unacceptable” feelings.

• He viewed the manifest content as a censored, symbolic storyline of a dream that we remember.

• The latent content is the underlying meaning of a dream, which is the unconscious drives and wishes that would be threatening if expressed directly.

Freud considered our dreams to be the key to understanding our inner conflicts, however, his critics regard them as a scientific nightmare.

Some critics of the wish-fulfillment theory say that if dreams are symbolic, they could be interpreted in any way one wishes, while others maintain that dreams hide nothing: a dream about a gun is a dream about a gun.

The information-processing perspective states that dreams may help sift, sort, and fix the day’s experiences in our memory and consolidate memories.

• Critics question this theory by asking: Why do we sometimes dream about things we have not experienced and about past events?

The physiological function states that regular brain stimulation from REM sleep may help develop new neural pathways.

• Critics state that this does not explain why we experience meaningful dreams.

The activation-synthesis perspective states that REM sleep triggers neural activity that evokes random visual memories, which our sleeping brain weaves into stories.

• Critics state that it is our brain weaving the stories, so this still tells us something about ourselves.

The cognitive development perspective states that dream content reflects dreamers’ level of cognitive development — their knowledge and understanding. Dreams stimulate our lives, including worst-case scenarios.

• Critics state that it does not propose an adaptive function of dreams.