Many people describe persistent fatigue as feeling like their body is stuck on high alert—reacting to everyday demands as if they’re threats. Research suggests that in conditions such as ME/CFS, long COVID, and post-viral fatigue, this may be due to autonomic dysregulation—the systems responsible for helping us respond to daily demands, and maintain balance, become overactive. Understanding the science behind fatigue can be empowering because it validates that what you’re feeling is real and physiological, and it provides a foundation for the strategies we use in therapy to support energy management
Our bodies are constantly working to respond to internal demands like hunger, sleep, and cognitive or physical effort, as well as external factors such as light, temperature, and noise. The aim is to maintain or return to a balanced state, known as homeostasis, which is essential for overall health and wellbeing. There are four key response systems (or processes) that work together to help the body adapt to changing demands.
1) The autonomic nervous system sends electrical signals from the brain and spinal cord to the rest of the body. It has two main branches—the parasympathetic system, which promotes rest and recovery, and the sympathetic system, which prepares the body for action and to respond to stressors.
2) The endocrine system consists of glands that secrete hormones directly into the bloodstream.
3)The immune system is made up of organs such as the spleen, bone marrow, and lymph nodes along with various types of immune cells.
4) Metabolism refers to the chemical processes that take place in the cells to produce the energy the body needs to meet different demands.
These systems act like a control room behind the scenes—constantly monitoring and adjusting to keep everything running smoothly, even when conditions change. In everyday life, they respond to small shifts automatically. Whether it’s sending signals to increase your heart rate when you walk faster, helping you cool down when you're too warm, sharpening your focus to meet a work deadline, or adjusting your sensitivity to noise, these systems are always working in the background.
When a more intense stressor occurs, such as illness, injury, or a difficult life event, these systems activate. They trigger a range of physiological responses, such as fatigue, pain, fever, anxiety, and the need to rest. These responses help the body fight the stressor and focus on healing. Once the stressor has passed, the systems return the body to balance, as this stress response is energy-intensive and not meant to be sustained long-term.
However, sometimes these systems get stuck in a heightened state of activity and sensitivity. Research suggests that all four of these systems (or processes) are impacted—both individually and in how they interact with each other.
For example:
- Ongoing immune activation can disrupt nervous system signaling and contribute to autonomic dysregulation.
- Hormonal dysregulation can increase immune system-led inflammation.
- An overactive nervous system can use up energy reserves more quickly.
The systems continue to respond as if there’s an ongoing threat, even when the original stressor is no longer present. This heightened state means the system becomes more sensitive, interpreting everyday activities (e.g., jogging, work), normal body processes (e.g., digestion), or environmental factors (e.g., noisy streets) as demanding or even as stressors. This ongoing activation can explain many of the symptoms people experience, such as fatigue, post-exertional malaise, pain, unrefreshing sleep, thinking problems (brain fog), digestive problems, sensitivity to light and sound, changes in heart rate, anxiety, and more.
Unfortunately, there isn’t currently a medical treatment that can directly reverse this kind of dysregulation. However, understanding the science behind persistent fatigue helps shape effective fatigue management, which focuses on supporting the body’s systems to gradually return to balance.
This includes:
- Noticing your symptoms as your body’s signals
- Recognising triggers and patterns
- Implementing nourishing actions into your routine
- Developing self-compassion
- Understanding how to stay within and return to your energy window
Therapy at Flourish with Fatigue is underpinned by this evidence-based approach, which helps to regulate the body’s systems by reducing the likelihood of overactivation and supporting stability. For personalised therapy, please book a discovery call.
We’ll continue to share evidence-based tips and resources through our blog, Instagram, and website to support you in managing fatigue.
References
- This blog is informed by recent scientific research published in Frontiers in Immunology:
Bautista-Gómez, M. M., Polidoro, M., Martinez-Murcia, A., de Lorenzo, A., Ocaña-Peinado, F. M., RodrÃguez-Molina, M. J., & Valdés, S. (2024). Pathophysiological, immunological, and inflammatory features of long COVID: A review. Frontiers in Immunology. https://doi.org/10.3389/fimmu.2024.1341600 - Komaroff, A. L., & Lipkin, W. I. (2024). Myalgic encephalomyelitis/chronic fatigue syndrome: The biology of a neglected disease. Frontiers in Immunology, 15, 1386607. https://doi.org/10.3389/fimmu.2024.1386607
Additional trusted resources:
- BACME – An Introduction to Dysregulation in ME/CFS: https://bacme.info/wp-content/uploads/2022/05/BACME-An-Introduction-to-Dysregulation-in-MECFS-1.pdf
- ME Association: https://meassociation.org.uk