In the hustling rhythm of modern life, it’s easy for your body’s stress-response system to kick into high gear. The sympathetic nervous system (SNS) is your body’s accelerator in stressful situations, ramping up your heart rate, increasing blood pressure, and preparing you to fight or flee. But what happens when your sympathetic nervous system goes into overdrive? Understanding the signs can help you regain balance and protect your health.
What is the Sympathetic and Parasympathetic Nervous system
The autonomic nervous system (ANS) is a critical regulator of many of the body’s automatic functions, such as heart rate, digestion, and respiratory rate. It is divided into two main branches: the sympathetic and parasympathetic nervous systems (Shaffer & Ginsberg, 2017).
These two systems work together to maintain balance, but they have opposing functions that help the body respond to different situations. The difference between sympathetic and parasympathetic nervous system functions is outlined below.
Sympathetic Nervous System: The “Fight or Flight” Response
The Sympathetic Nervous System (SNS) is often referred to as the “fight or flight” system. It is activated when the body perceives a threat or stressor, whether physical or emotional. In response, the sympathetic system triggers a range of physiological changes, including:
- Increased heart rate and blood pressure to deliver more oxygen to muscles (Thayer et al., 2012).
- Dilation of the airways to enhance breathing (McEwen, 2007).
- Suppression of digestion to conserve energy for dealing with the perceived threat (Selye, 1950).
Sympathetic Nervous System function include activating the body for rapid action, enabling it to handle stress and potential danger. However, chronic activation of the sympathetic nervous system, as seen in individuals experiencing CNS fatigue or chronic stress, can lead to detrimental effects on health such as physical and mental health issues (Berntson & Cacioppo, 2000).
Parasympathetic Nervous System: The “Rest and Digest” Response
In contrast, the parasympathetic nervous system is responsible for promoting relaxation and recovery. Often called the “rest and digest” system, it encourages functions that help the body conserve energy and recover (Porges, 2007). When the parasympathetic system is dominant, you may experience:
- Slower heart rate and lower blood pressure (Shaffer & Ginsberg, 2017).
- Enhanced digestion and nutrient absorption (Selye, 1950).
- Relaxation of muscles and a sense of calm (McEwen, 2007).
The parasympathetic nervous system is most active when the body is at rest and not facing immediate stressors. It is crucial for recovery from exercise or stress and plays a key role in counteracting the effects of sympathetic nervous system activation.
Signs of Sympathetic Nervous System Overdrive
- Increased heart rate: If your heart often races or you notice palpitations in non-threatening situations, it could be a sign that your SNS is overly active (Thayer et al., 2012).
- High blood pressure: Persistent high blood pressure might be another signal. The SNS raises blood pressure to increase blood flow during stressful situations, but over time, this can strain your cardiovascular system (McEwen, 2007).
- Sleep problems: Trouble falling asleep or staying asleep can be linked to an overactive SNS. High stress levels can make it difficult for the body to transition into the calm state necessary for deep sleep (Selye, 1950).
- Anxiety or irritability: Mental health can also be affected by an SNS in overdrive. If you find yourself constantly feeling on edge, anxious, or unusually irritable, it might be time to assess your stress levels (Berntson & Cacioppo, 2000).
- Sweating: Excessive sweating, especially when not physically exerting yourself, is a classic sign of SNS activation (Thayer et al., 2012).
- Digestive issues: The SNS diverts blood away from the stomach and intestines and toward the muscles during stress, which can lead to digestive problems like nausea, indigestion, or diarrhea (McEwen, 2007).
Managing an overactive Sympathetic Nervous System
If you suspect your Sympathetic Nervous System is often in overdrive, there are several strategies you can implement to encourage a shift toward a more balanced autonomic state:
- Mindfulness and meditation: Practices like mindfulness, meditation, and deep-breathing exercises can activate the parasympathetic nervous system (PNS), the counterbalance to the Sympathetic Nervous System, promoting relaxation and recovery (Porges, 2007).
- Regular exercise: Physical activity, especially aerobic exercise, can help metabolize excess stress hormones, enhancing your mood and overall sense of well-being (Thayer et al., 2012).
- Adequate sleep: Prioritizing good sleep hygiene—such as a regular sleep schedule, a dark and cool bedroom, and avoiding screens before bed—can help reduce SNS activity (McEwen, 2007).
- Healthy diet: Eating a balanced diet rich in fruits, vegetables, whole grains, and lean proteins can support overall health and help regulate stress responses (Selye, 1950).
- Professional support: If stress feels unmanageable, consider seeking support from a mental health professional or counselor who can offer strategies and support to manage anxiety and stress (Berntson & Cacioppo, 2000).
- Spend time with loved ones: Engaging with friends, family, and community can provide emotional support and reduce stress. Activities that foster positive social interactions can help moderate the body’s stress responses (Porges, 2007).
Monitoring Your Autonomic Nervous System
For those interested in a more tech-savvy approach, you can monitor signs of SNS activity with the Biostrap Kairos. Its novel Spot Check features provides insights into your ANS balance, HRV data and heart rate, so you can use that data as a feedback loop to better understand the impact your lifestyle choices has on your well-being. By tracking these metrics, you can get real-time feedback on your body’s stress levels and the effectiveness of various interventions (Shaffer & Ginsberg, 2017).
Recognizing when your SNS is in overdrive is crucial for maintaining both physical and mental health. By understanding the signs and taking proactive steps to manage stress, you can help ensure your body’s stress response works for you—not against you. In doing so, you create a more balanced, healthier life that allows for both productivity and relaxation.
References
Berntson, G. G., & Cacioppo, J. T. (2000). Heart rate variability: Stress and psychiatric conditions. In M. H. Agelink, A. Bozbas, & H. E. Weiss (Eds.), Autonomic Dysfunction and Psychiatric Disorders (pp. 57-64). Karger Publishers.
McEwen, B. S. (2007). Physiology and neurobiology of stress and adaptation: Central role of the brain. Physiological Reviews, 87(3), 873-904. https://doi.org/10.1152/physrev.00041.2006
Porges, S. W. (2007). The polyvagal perspective. Biological Psychology, 74(2), 116-143. https://doi.org/10.1016/j.biopsycho.2006.06.009
Selye, H. (1950). Stress and the general adaptation syndrome. British Medical Journal, 1(4667), 1383-1392. https://doi.org/10.1136/bmj.1.4667.1383
Shaffer, F., & Ginsberg, J. P. (2017). An overview of heart rate variability metrics and norms. Frontiers in Public Health, 5, 258. https://doi.org/10.3389/fpubh.2017.00258
Thayer, J. F., Åhs, F., Fredrikson, M., Sollers, J. J., & Wager, T. D. (2012). A meta-analysis of heart rate variability and neuroimaging studies: Implications for heart rate variability as a marker of stress and health. Neuroscience & Biobehavioral Reviews, 36(2), 747-756. https://doi.org/10.1016/j.neubiorev.2011.11.009
