What is an Overactive Nervous System?

Amy Barczy

| 3 min read

Amy Barczy is a brand journalist at Blue Cross Blue Shield of Michigan and writes for AHealthierMichigan.org and MIBluesPerspectives.com. Prior to joining Blue Cross, she was a statewide news reporter for MLive.com. She has a decade of storytelling experience in local news media markets including Lansing, Grand Rapids, Holland, Ann Arbor and Port Huron.

You may have heard of the body’s “fight or flight” response. It's how our body is hard-wired to protect itself in stressful situations. This is part of our body’s nervous system and is deeply connected to many of our day-to-day functions. However, certain behaviors and chronic conditions can affect our nervous system, causing damage. Chronic stress and anxiety can affect the nervous system as well.

What is the sympathetic nervous system?

The sympathetic nervous system is responsible for many of the bodily functions that you don’t have to consciously think about to control, like your heart rate, blood pressure, digesting food, urinating and sweating. The system is rooted in the body’s spinal cord and sends signals throughout the body.
Its most significant role is cuing the body to respond to dangers, threats, or stress – the “fight or flight” response.
This is why when we’re suddenly scared, for example, our heart rate speeds up. The sympathetic nervous system pushes more blood to different parts of the body that need to respond if you’re in danger:
  • Pupils in the eyes will widen to improve vision
  • Heart rate will increase
  • Airway muscles will relax to allow more oxygen to the lungs
  • Digestion will slow as energy is directed to other parts of the body
  • Energy stores from the liver will be activated for quick use
This response is designed to help our body in situations where we need to act quickly or think fast. But the sympathetic nervous system isn’t just used when we’re presented with a threat: it can activate during exercise, or when you are sick or injured to boost the repair process.

What is the parasympathetic nervous system?

The parasympathetic nervous system acts as the antidote to the sympathetic nervous system. After your body manages the threat or danger, the parasympathetic nervous system sends signals out to the body to return functions back to normal.

What conditions affect the sympathetic nervous system?

Several conditions can affect the nervous system. Those include:
  • Type 2 diabetes
  • Anxiety disorders and chronic stress
  • Cancer
  • Genetic conditions like amyloidosis
  • Horner’s syndrome
  • Infections
  • Multiple system atrophy
  • Sexual dysfunction
  • Trauma

Can the nervous system be overactive?

Chronic stress or anxiety can cause the body’s “fight or flight” response to become constant – leading to an overactive nervous system. This can cause symptoms including:
  • Physical symptoms, including weight gain, body aches and pains, chest pain, diarrhea or constipation, nausea, dizziness and weak immunity
  • Behavioral symptoms, including eating more or less, changes in sleep patterns, nervous habits, isolating yourself, relying on substances to relax, avoiding responsibilities
  • Cognitive symptoms, including memory problems, inability to concentrate, poor judgement, increased negativity and anxious thoughts
  • Emotional symptoms, including moodiness, irritability, short temper, agitation, inability to relax, overwhelm, feeling isolated, depressed or unhappy
Additionally, conditions can affect or damage the sympathetic nervous system. For example, Type 2 diabetes can damage the nerves over time.

Ways to protect the sympathetic nervous system

While some conditions that affect the sympathetic nervous system cannot be prevented, there are ways to delay the onset of some conditions and to live the healthiest life possible. Preventive measures to take that can benefit many of your body’s systems include:
  • Eat a balanced diet complete with whole grains, healthy fats, proteins and fresh produce and drink the recommended amount of water each day
  • Avoid abusing substances, including drugs and alcohol that can damage the sympathetic nervous system
  • Stay physically active and maintain a healthy weight
  • Wear safety equipment as needed while at work or at play to prevent damage from injuries
  • Manage chronic conditions
If you have concerns about your nervous system, talk with your health care provider about your observed symptoms and your lifestyle.

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