A human's nervous system is considered in two part: the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS). These two parts are responsible for arousing the human into action (SNS) or calming the system back down to a baseline (PNS). For neurodivergent individuals, these systems can respond differently than for neurotypical people.
The Sympathetic Nervous System (SNS)
The sympathetic nervous system is responsible for activating the body's stress response. This system becomes especially evident during moments of stress, as it triggers what is commonly known as the "fight or flight" response. When this response is activated (hyperaroused), the body undergoes a series of changes designed to protect us from perceived threats by preparing for action. These changes include increased heart rate, faster breathing, elevated blood pressure, dilated pupils, and muscle tension.
In addition to these physical changes, the body also releases stress hormones, such as adrenaline and cortisol, which boost energy and enhance the body's ability to cope with stress. Some of the physiological changes associated with the activation of the sympathetic nervous system include:
Tensed muscles
Heightened energy and vigilance
Variations in heart rate & higher blood pressure
Rapid, shallow breathing
Elevated levels of adrenaline and cortisol
Enlarged pupils
Lowered sexual arousal
Narrowed focus
Reduced immune function & slower digestion
These changes prioritize survival by enabling the body to either confront a threat or escape from it. They also enhance sensory awareness and suppress processes that are not immediately essential, such as digestion and immune function. Importantly, these responses occur automatically, without conscious control. The body will activate the stress response to any perceived threat, regardless of how logical or minor it may seem. For example, the reaction could be the same whether one is being pursued by a predator or asked for a private conversation by your trainer.
For neurodivergent individuals, this response can be triggered more easily due to many factors including having a heightened sensitivity to external stimuli. For instance, loud noises or unexpected touch may provoke the same stress response as a more overt threat. Research suggests that Autists and ADHDers have significant differences in the way their SNS responds and how it communicates to different systems in the body. Research in this area is helping us learn more about comorbidities (other health issues) that neurodivergent people experience and establishes that these biological differences are real and not imagined. This in turn helps us to recognise that our bodies need help when they are activated.
Hypoarousal in Response to Acute Stress
The activation of the sympathetic nervous system (SNS) is commonly associated with a hyperaroused state, where "hyper" signifies "over." This is the classic "fight or flight" response. However, individuals may also experience a hypoaroused state, with "hypo" meaning "under." While hyperarousal mobilizes the body for action, hypoarousal represents a "freeze" response, where the body slows down significantly.
When exposed to acute stress, the body can enter hypoarousal, characterized by a dramatic reduction in nervous system activity. Unlike the heightened activity of hyperarousal, hypoarousal involves a shutdown of both physical and mental processes. Common symptoms of this state include profound fatigue, dissociation, numbness, mental fog, and even physical immobility.
Hypoarousal is thought to be an evolutionary adaptation designed to protect the body from overwhelming stress or trauma. By suppressing sensory input and mental activity, this response reduces the perception of pain and distress, functioning similarly to the "playing dead" survival tactic observed in some animals. Although this response can be protective in the short term, it can become detrimental if prolonged.
How this information can be helpful
For neurodivergent individuals, persistent stress without adequate recovery can trap the body in a state of either hyperarousal or hypoarousal. Prolonged defensive activated mechanisms or shutdowns may lead to chronic symptoms which may exacerbate challenging experiences. In these states, the body may struggle to either recover to a baseline or to detect safety, remaining locked in a mode of survival and making it difficult to regain balance and well-being.
Understanding the unconscious activation of the body responding to its environment or stressful situations can help us develop the vital self-compassion needed to rest and recuperate as much as possible. Neurodivergent bodies are different and often respond as if they are under constant threat. Understanding that this can be exhausting and often debilitating can help support beneficial changes to help neurodivergent bodies experience improvements in wellbeing.
Viewing these experiences through a biological lens can help to identify what might be activating or inactivating phenomena, which can help inform the development of strategies to help the nervous system become more stabilised.
Comments