As a person with insomnia, I often have trouble falling asleep and have always wondered why I feel cranky after a night of only a few hours sleep.
Most people, at least once in our lives, will have experienced the sense of irritability and nervousness after a sleepless night, especially in case of a subsequent busy day. During my degree course in Health Psychology, I studied the relationship between cognitive and emotional factors, as well as behavioral variables, such as sleep quality, and clinical variables like depression and anxiety. Therefore, my background in this field led me to ponder on the link between our emotions and the previous night's sleep.
Although the precise functions of sleep remains elusive, evidence shows that sleep disturbances and sleep loss might have a crucial role in multiple domains of our affective functioning, which includes emotion, emotion regulation, emotional intelligence, emotional memory, and facial recognition of emotion, and I aim to discuss by introducing the concept of the Cognitive Energy Model in this article.
Emotions, mood and emotion regulation
It is first important to define the difference between emotions, mood and emotion regulation.
We use the term “emotion” all the time and what often comes to mind is something like anger, sadness, or happiness, but all these instances have different components. In fact, when we talk about emotions, we refer to the subjective aspects of our experiences, which are reflected as either positive or negative feelings. Therefore, we describe happiness as a positive emotion, while anger as a negative one.
In addition to that, emotions have a behavioural component because they are displayed on facial expressions or through behaviour. They also have a physiological component represented by bodily responses such as change in blood pressure or sweaty palms. Thus, emotions could be defined as the connecting point of these subjective experiences as well as behavioural and physiological responses.
When it comes to the difference between emotion and mood, the latter is described as a longer-lasting state of mind that could persist hours to weeks.
Moreover, emotions are caused by specific events so that a person is happy about something, angry at someone or afraid of something, whereas mood isn’t always associated with a specific and clear cause. Finally, emotions usually have a high intensity, whereas mood has a lower one.
When talking about emotion regulation, this could be defined as the process that takes place every day when we try to modify the emotions that we feel, how we express them and how they affect our behaviour. For example when we feel grumpy in the morning but we have to be kind with our colleagues or friends, or when we feel down but we need to attend our best friend’s birthday party. In both situations we try to change and modify our bodily and emotional responses in order to keep up with our schedule.
The relationship between emotions, emotion regulation and sleep loss
Research shows that the relationship between emotion, emotion regulation, and sleep loss might be bidirectional. This means that not only can poor sleep take a heavy toll on affective functioning, but also a daily affective state can affect the quality and duration of sleep. For example, experiencing a sleepless night can make us feel grumpy or cranky in the morning. Even being nervous or broody can disturb our sleep. Although this phenomenon may be something we all encounter at some point in our lives, its causes and underlying mechanisms are not fully understood.
Several studies demonstrated how major long-term sleep disturbances are associated with more persistently negative emotions such as irritability, anxiety and nervousness, whereas higher levels of positive emotions, such as tranquillity, happiness, and a good mood, are connected with better sleep quality, as perceived subjectively.
The Cognitive Energy Model
Zohar and his team proposed the Cognitive Energy Model in order to explain the link between sleep loss and negative emotions.
Cognitive Energy is an important resource because it allows us to not only regulate and sustain our actions, but also to apply emotion regulation to our experiences. Cognitive energy is the element that helps us perform everyday tasks, as well as concentrate on our work and socialise with people and friends. It is the ingredient that enables us to achieve our goals while also dealing with the unforeseen (when we perceive it in trouble). Cognitive energy is extremely important because it has a crucial role in our lives even though it’s finite, rapidly consumed and slow to recover.
Cognitive energy is supposed to be linked with sleep because during the day we consume all of this energy in our daily activities, and it is then recharged during our time asleep at night. For this reason, and according to this model, sleep loss reduces cognitive energy supplies for our activities, leading to impaired performance, frustration, and irritability because we are not able to do what we have to do during our daily life. In addition to that, the lack of availability of cognitive energy holds us from regulating negative emotions and it can even exacerbate them.
Why the Cognitive Energy Model is linked to sleep loss
Everyday life is full of affective events, situations or circumstances that provoke emotional reactions in people (for example, an argument or receiving good news) and that require a change of plans, along with regulation of behaviours and emotions. Unless the available energy resources match the demands associated with our activities, this misfit will be assessed as a threat, resulting in negative emotions such as irritability and nervousness.
So cognitive energy is a very crucial element within the relation between sleep loss and negative emotions. This construct helps us to better understand the reason why after a sleepless night we experience more negative emotions like frustration and nervousness.