Arousal and Wakefulness

Last updated: March 28, 2019

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What is the difference between arousal and wakefulness?

Arousal and wakefulness are two terms that we often incorrectly interchange. These two terms are often used in connection with sleep.

Sleep and wakefulness are easy to define and quantify. When we say sleep, we envision a person who is immobile, with their eyes closed and breathing shallowly. Sleep often involves a long period of inactivity and unconsciousness. These two states are quantitatively identified and characterized by patterns of cortical activity on an electroencephalogram (EEG). We can also use the intensity of motor activity on an electromyogram (EMG) to identify these two states.

If a person is awake, then that person is active and has open eyes. That person can perceive and interact with the environment. The term “arousal” refers to the degree of alertness and vigilance displayed by a person during wakefulness. You can be awake but not in a state of arousal. You could just be lounging on your couch without doing anything. It is impossible to be in a state of arousal without being awake.

Why is arousal important?

When a person is aroused they have increased motor activity. That person responds to sensory inputs, has emotional reactivity, and possess enhanced cognitive processing. Arousal systems also increase a person’s vigilance. This means that you can properly react to a stressor. You can also initiate a flight or fight response. Arousal also lets you initiate courtship and reproductive behaviors. It is only when you get aroused that you can engage in goal-directed behaviors that are vital for behavioral adaptation and survival.

In psychology, mild perturbations of arousal can be a signal of psychiatric disorders. Hyperarousal is a symptom of schizophrenia. It can also be a symptom of addiction, and general anxiety disorder (GAD). On the other hand, hypoarousal is associated with aggressiveness and attention deficit hyperactivity disorder or ADHD.  

A distinct neural population in the brain regulates a person’s arousal. Activity in these nuclei is a sign of arousal. The activity of these nuclei increases when a person is awake. This activity also increases when a person is in a state of enhanced arousal. For example, a person is in a state of enhanced arousal during moments when he experiences stress or if he is in a dangerous situation.

The arousal systems in the brain are not just concerned with wakefulness. These systems also engage other arousal-related behaviors. Examples of these behaviors are reward-seeking, flight or fight responses, or sexual activity.

Arousal disorders in children

It may be hard to believe, but arousal disorders are common in children. It is not complete arousal though since the child is not awake. This is partial arousal from deep sleep or REM sleep. A partial arousal like this is called slow wave sleep. A child transitions from deep sleep to very light sleep or partial wakefulness.

When a child is in this stage, you may see the child as being both awake and asleep. Sometimes, you’d see a child appearing confused or disoriented while sleeping. You’d even see a child sit up or mumble before going back to sleep. In more serious cases, a child might cry as if agitated and won’t settle down even if you talk to him or her. We often ignore this kind of behavior and just think of it as a child having bad dreams.

Children with arousal disorders can also display more complex behaviors. Sleepwalking is a possibility. A child may get up from the bed and walk into a closet thinking that the closet is the bathroom. The child may even urinate in the closet before returning to bed. Most of the time, a child would have no memory of such episodes.

What can cause arousal disorders in children?

There are several triggers that can cause arousal disorders. An undetected health issue might be the cause. Several health problems like fever and migraine can result in this disorder. Abrupt loss of sleep or an irregular sleep schedule are also common causes. In older teenagers, the behavior associated with arousal disorders can be a result of sleep deprivation or alcohol intake.

Arousal and sleep are two states that are always intertwined. We are able to function properly and go about our day-to-day activities when we are in a state of arousal. Sleep, on the other hand, lets us rest our body so we can recover the energy that we spent the entire day. Sleep is also how we heal our body from any injuries we may have incurred during the day.

It may be hard to believe but there are arousal disorders common to children. We often disregard them and just think of them as the quirks of childhood. However, they may be because of another health issue that we just haven’t detected yet.

Sometimes, we are so busy trying to figure out how to get enough sleep that we forget that even our children need a good night’s rest too. Their bodies also need to rest and heal. Understanding these disorders can help us ensure that whatever sleep disorder our children has can be taken cared of before they get out of hand.

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