Nightmares are particularly vivid and distressing dream activities that occur mainly in the REM phase of sleep. These are not just “bad dreams”, but a significantly negative experience for those who live it and which affects not only the quality of sleep but also the mood when waking up. In fact, the feeling of malaise lasts for a good part of the following day. Responsible for this anguish seems to be not only the release of cortisol which induces a feeling of stress during the nightmare, but also the failure to process negative emotions and worries experienced during the day.
What are night terrors
Nightmares are a particular type of dream that occurs in the REM (or Rapid Eye Movement) phase, characterized by contents that have a negative impact on the person experiencing it who experiences a series of intense emotions (fear, sadness, desperation or anger). The immediate consequence, beyond any momentary fear, is the continuation of a state of anguish which makes sleep light and easily disturbed and which can sometimes last for a good part of the following day. Nightmares tend to occur in the early hours of dawn and are characterized by the fact that the subject can completely and vividly remember their contents upon awakening. Typically, the duration of the event is short (about 4-15 minutes) but often, the subject may not be able to fall back to sleep.
For specialists, from the point of view of definition, there is a significant difference between a real nightmare and a bad dream: at the end of the nightmare you always wake up. Some people suffer from what the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) calls “Nightmare Disorder” (parasomnia) and occurs when this type of dream event is so intense and frequent that it causes significant distress or impairment in daytime functioning. In some cases you can even fear the moment of falling asleep, experiencing the so-called “night terror”.
At the top of the list of recurring nightmare themes are:
- Aggression and interpersonal conflicts;
- Personal failures or situations in which it is impossible to save oneself;
- Concerns about health or other aspects of one’s integrity.
- Precipitate;
- Being chased and feeling paralyzed;
- Being late for an important event or appointment.
What happens in our brain during a nightmare
When we have a nightmare, specific areas linked to emotions and memory are activated in the brain. A recent study observed from analysis with EEG (electroencephalogram) and fMRI (functional magnetic resonance imaging), that emotions in dreams and in waking life involve similar neural substrates, supporting the fact that there is a link between the emotional processes that occur during a nightmare and emotional brain functions during wakefulness.
It is widely believed that the areas responsible for managing emotions and consolidating memories remain hyperactive even during the nightmare, giving it that character of vividness (since they could be based on something we actually experienced during the day) and emotional intensity. On a physical level, this translates into physiological changes that can also be observed from the outside. Specifically, the release of cortisol, the stress hormone, causes a state of agitation and restlessness which manifests itself in a similar way in anxious states: tachycardia, acceleration of breathing, tremor in the hands or legs, increased sweating. These are all symptoms that indicate that the body is in a state of alert, as if it was expecting a sudden attack and preparing to escape. This condition tends to persist and hinders falling back to sleep.
How come we remain restless even after waking up
Although it is a feeling presumably shared by everyone, there is no single answer that precisely explains why one remains distressed after a nightmare or a bad dream. What we know for sure is that during the night, our brain continues to process the information we have collected during the day. When we fall asleep, the alert level is very low, but not completely absent: a minimum threshold of perception is always directed outwards (for example to allow us to notice sudden noises that may represent a possible danger). Thus, the emotional states that cause us worry during the day find a new channel of expression in nightmares, taking advantage of the fact that we are unable to control them while we sleep: it has in fact been observed that night terrors are more frequent among people who try to ward off intrusive thoughts and fears during the day, effectively preventing their conscious processing. Their manifestation therefore takes shape through frightening or painful images, sometimes so vivid and realistic that they cause a real sense of discomfort even later. There is also a widespread hypothesis that nightmares are a sort of simulation that the brain puts in place to prepare us to react to real or perceived dangers.
Therefore we can summarize in this list the reasons why it becomes difficult to chase away restlessness and anguish when waking up from a nightmare:
- Activation of the stress response: Upon awakening from a nightmare, the body is in a state of alert, “preparing to escape.” This is due to the involvement of the amygdala (the part of the brain linked to fearful emotions) and the release of stress hormones, which can take time to be eliminated.
- Difficulty returning to reality: the feeling of discomfort may persist because the brain does not immediately “turn off” the emotional response to the nightmare, making it difficult to return to tranquility and relaxation.
- Processing unresolved emotions: Nightmares may be the brain’s way of processing frightening experiences or trauma. If these are not adequately addressed during the day, they can manifest themselves at night, leaving an emotional trace that affects the following day.
