Sympathetic Nervous System

Definition

The sympathetic nervous system (SNS) is part of the autonomic nervous system that prepares the body for 'fight or flight' responses during stressful situations. It increases heart rate, dilates airways, and mobilizes energy resources, all of which are vital adaptations during exercise or periods of overtraining. The SNS plays a crucial role in regulating cardiovascular responses, particularly as the body copes with physical exertion and stress.

5 Must Know Facts For Your Next Test

1. The sympathetic nervous system is activated during physical exercise, leading to increased heart rate and blood flow to muscles.
2. Overtraining syndrome can lead to an imbalance where the sympathetic nervous system remains overly active, causing chronic fatigue and stress.
3. During prolonged exercise, catecholamines from the sympathetic nervous system help maintain energy levels by increasing glucose availability.
4. The 'fight or flight' response initiated by the SNS can lead to beneficial adaptations in athletes, such as improved cardiovascular efficiency.
5. Balancing the activity of the sympathetic and parasympathetic nervous systems is essential for optimal recovery and performance in sports.

Review Questions

• How does the sympathetic nervous system adapt cardiovascular functions during exercise?
  • During exercise, the sympathetic nervous system increases heart rate and cardiac output, ensuring that more oxygen-rich blood is delivered to active muscles. This response allows athletes to sustain higher levels of intensity and performance. Additionally, it causes vasodilation in skeletal muscles while constricting blood vessels in less active areas, optimizing blood flow where it’s needed most.
• Discuss how overtraining syndrome relates to sympathetic nervous system activity and its effects on athletic performance.
  • Overtraining syndrome is characterized by prolonged fatigue, decreased performance, and altered mood states. In this condition, the sympathetic nervous system can remain chronically activated due to excessive training without adequate recovery. This sustained activation leads to an imbalance that disrupts normal physiological functions, resulting in issues like increased resting heart rate and elevated levels of stress hormones, negatively impacting overall performance.
• Evaluate the implications of sympathetic nervous system activation on both short-term performance enhancements and long-term athlete health.
  • Sympathetic nervous system activation provides immediate benefits for short-term performance by enhancing cardiovascular responses and energy mobilization. However, if this activation persists due to factors like chronic stress or overtraining, it can lead to negative health outcomes such as increased injury risk and hormonal imbalances. Athletes must find a balance between leveraging these acute benefits for competition while managing stressors that could lead to long-term health issues.

Related terms

Parasympathetic Nervous System:

The part of the autonomic nervous system that promotes 'rest and digest' functions, counterbalancing the effects of the sympathetic nervous system.

Catecholamines: Hormones like adrenaline and norepinephrine released by the adrenal glands during stress, which activate the sympathetic nervous system.

Heart Rate Variability: The measure of variation in time between heartbeats, which can be influenced by the balance between the sympathetic and parasympathetic nervous systems.