Lecture Notes: Autonomic Nervous System Across the Lifespan
I. Beyond “Fight or Flight” and “Rest and Digest”
- The lecture clarifies that sympathetic and parasympathetic activity isn’t always at extremes.
- We typically exist in a dynamic balance between the two, with shifts based on immediate needs (e.g., encountering a threat vs. relaxing after a meal).
II. Sympathetic Dominance Across the Lifespan
- An additional layer of complexity is the gradual shift towards sympathetic dominance throughout life.
- Young children: More parasympathetically dominant, focusing on growth and nutrient absorption.
- Older adults: More sympathetically dominant, potentially contributing to conditions like hypertension.
III. Factors Influencing Autonomic Tone
- Physical activity: Highly trained aerobic athletes exhibit stronger parasympathetic dominance (e.g., lower resting heart rate).
- Age: As we age, the natural shift towards sympathetic dominance may contribute to age-related health concerns like hypertension.
IV. Connection to Future Lecture
- The lecture concludes by foreshadowing a future segment discussing drugs targeting the autonomic nervous system to manage conditions like hypertension.
V. Key Takeaways
- The autonomic nervous system’s activity isn’t solely “fight or flight” or “rest and digest.”
- A balance exists between sympathetic and parasympathetic activity, shifting based on immediate needs and life stage.
- Sympathetic dominance increases with age, potentially impacting health.