The arrival of the cold season often brings a familiar sense of unease. As the days shorten and temperatures drop, many of us feel more run-down, susceptible to illness, and generally less vibrant. We experience the frustrating cycle of winter colds, sinus pressure, and that persistent feeling of being “stuck” in a state of stress. At the heart of this seasonal struggle is a system under strain: a dysregulated nervous system leading to compromised immunity and sluggish circulation. 

While chiropractic care is widely recognized for addressing back and neck pain, its influence extends far deeper. This article moves beyond the back to provide a definitive, evidence-informed explanation of how chiropractic care fundamentally works: by regulating the body’s master control system—the nervous system. 

Why Your Body Struggles More in the Cold Season

It’s a common belief that simply being in the cold is what makes us sick. However, the reality is more complex. The winter months create a “perfect storm” of physiological and behavioral changes that challenge our body’s resilience. The primary culprits aren’t the cold temperatures themselves, but rather our body’s reaction to them and the environments we inhabit. 

Research shows that our immune systems exhibit seasonal patterns. A large-scale study of over 329,000 participants from the UK Biobank found evidence for seasonal variation in multiple immune parameters, including the levels of white blood cells, which are crucial for fighting infection[1]. Furthermore, exposure to cold can trigger systemic changes. A cohort study published in Environmental Health discovered an association between lower outdoor temperatures and an increase in markers of systemic inflammation, such as C-reactive protein[2]. This low-grade inflammatory state can tax the immune system, leaving it less prepared to fight off pathogens. 

What Cold Weather Does to Circulation and Immunity

When your body is exposed to cold, it initiates a protective mechanism called vasoconstriction, where blood vessels, particularly in your extremities like hands and feet, narrow to conserve core body heat. While essential for survival, this process is the reason for symptoms of poor circulation in cold weather, such as cold hands and feet, numbness, or even pain. This reduced blood flow can slow the delivery of vital oxygen and nutrients to tissues.

Behaviorally, we spend more time indoors during winter, increasing our proximity to others and raising the potential for pathogen transmission. The cold, dry air of heated indoor environments also allows aerosolized virus particles to remain airborne longer and travel farther, increasing our exposure risk. This combination of increased inflammatory load^[2], seasonally shifting immune cell counts^[1], and greater pathogen exposure creates a challenging environment for our health.

How Does Chiropractic Care Support Your Immune System?

The connection between chiropractic care and the immune system is a topic of significant interest and ongoing research. The foundational concept is psychoneuroimmunology (PNI), the scientific field dedicated to studying the intricate, bidirectional communication between the brain, the nervous system, and the immune system. Your nervous system acts as the master communication network, and any interference in its signaling can theoretically impact every other system it controls, including the immune system. 

It is crucial to approach this topic with scientific transparency. A 2021 systematic review published in JAMA Network Open assessed studies on spinal manipulative therapy (SMT) and the immune system. The authors concluded that while some studies suggest a potential link, the overall evidence is currently limited, and more high-quality research is needed to draw definitive conclusions[3]. This highlights the importance of viewing chiropractic not as a “cure” for illness, but as a strategy to support the body’s overall function and adaptability. The salutogenic model, which focuses on factors that support human health and well-being rather than on factors that cause disease, provides a useful framework. A review in Cureus explored this model, suggesting chiropractic care can influence the neuroendocrine-immune system by helping the body better adapt to stressors[4]. 

How Chiropractic Adjustments Affect Immune-Related Nerve Communication

The theoretical basis for chiropractic adjustment‘s influence on immunity lies in the integrity of nerve communication. The spine protects the spinal cord, which is the primary information highway between your brain and the rest of your body, including organs vital to immune function like the spleen, thymus, and lymph nodes. Chiropractic theory proposes that biomechanical issues in the spine—often termed vertebral subluxations—can create neural dysfunction that interferes with this communication. 

This interference can be thought of as “static on the line,” potentially disrupting the precise signals the nervous system sends to coordinate a balanced and effective immune response. As the review on systems biology and chiropractic explains, the goal of a spinal adjustment is to restore proper motion and neurological function [4]. By reducing this neural interference, the adjustment may help optimize the signaling pathways of the neuroendocrine-immune axis. It is a plausible mechanism, but as the JAMA review notes, it is one that requires further robust clinical validation [3]. 

How Reduced Stress and Inflammation Improve Immune Resilience

Perhaps the most well-supported pathway through which chiropractic care can support immunity is indirect: through the reduction of physiological stress and its associated inflammation. Chronic stress leads to persistently elevated levels of the hormone cortisol. While cortisol is vital in short bursts, chronic elevation actively suppresses the immune system, making you more vulnerable to infection. 

There is a direct, scientific link between the balance of the autonomic nervous system (ANS) and the body’s inflammatory state. A 2022 review in Autoimmunity Reviews details this interplay, showing how a well-regulated nervous system can help control inflammation[5]. Furthermore, correctable physical factors like posture have a measurable impact on stress hormones. A 2019 study found that poor, slumped posture was associated with higher levels of salivary cortisol[6]. By addressing postural distortions and improving spinal mechanics, chiropractic care can help reduce a chronic physical stressor on the body. This, in turn, can help lower the stress response, decrease systemic inflammation, and create an internal environment where the immune system can function with greater resilience. 

How Does Chiropractic Care Improve Circulation?

Beyond immunity, one of the most significant systemic benefits of a well-regulated nervous system is improved circulation. The nervous system directly controls the tone of your blood vessels—telling them when to constrict (narrow) and when to dilate (widen). Spinal health is intimately connected to the nerves that govern this vascular function. Direct evidence supports this connection. A 2023 randomized study published in the Journal of Chiropractic Medicine investigated the effects of spinal manipulation on blood flow. The researchers found that manual spinal manipulation applied to the neck resulted in measurable increases in blood flow through the vertebral and internal carotid arteries, which are major vessels supplying the brain [7]. This demonstrates that a mechanical input to the spine can have a direct and immediate physiological effect on vascular function.  

How Chiropractic Adjustments Help Blood Flow and Nutrient Delivery

How does a spinal chiropractic adjustment achieve this? The answer lies in modulating the autonomic nerve signals that control your blood vessels. The sympathetic chain ganglia, which are crucial relay points for “fight-or-flight” signals that cause vasoconstriction, lie along the front and sides of the spinal column. Spinal adjustments can reduce surrounding muscle tension and provide powerful mechanical and sensory input to the nervous system. This input can help modulate the output from these ganglia, leading to a decrease in vasoconstrictive signals and allowing for vasodilation. 

Think of it like removing a kink in a hose. The adjustment helps restore the normal nerve signals that tell the blood vessels how wide to be, allowing for smoother flow. The Kocabey et al. study confirmed this effect, concluding that SMT can cause “a significant increase in blood flow volume, peak systolic velocity, and end-diastolic velocity of the vertebral artery” [7]. This improved blood flow enhances the delivery of oxygen and nutrients to all of the body’s tissues, promoting better function and healing. 

Why Better Circulation Matters for Fighting Winter Colds

This link between chiropractic care and circulation is directly relevant to your ability to fight off winter illness. Your circulatory system is the transportation network for your immune cells. When you are exposed to a virus or bacteria, immune cells like lymphocytes and neutrophils must travel through the bloodstream to reach the site of infection and neutralize the threat. 

If your circulation is poor—whether due to cold-induced vasoconstriction or underlying neural dysfunction—this immune response can be delayed and less effective. Improved blood flow means a quicker and more robust deployment of your body’s “first responders.” Additionally, efficient circulation is essential for clearing away metabolic waste and inflammatory byproducts from infected or damaged tissues, which is a critical step in the recovery and healing process. 

How Does Chiropractic Care Regulate the Nervous System?

The regulation of the autonomic nervous system (ANS) is the central mechanism through which chiropractic care exerts its systemic effects on immunity, circulation, and overall well-being. The ANS is the subconscious part of your nervous system, operating in the background to control vital functions like heart rate, digestion, and, as discussed, blood vessel tone and immune activity. It has two main branches: the sympathetic system, our “fight-or-flight” accelerator, and the parasympathetic system, our “rest-and-digest” brake. 

A recent systematic review and meta-analysis confirmed that spinal manipulation is effective in influencing the ANS, showing measurable changes in markers like heart rate variability and skin conductance [8]. Furthermore, research into the neuroplastic effects of chiropractic suggests these changes may not just be temporary. A 2024 review in Medicina highlights that chiropractic care can induce neuroplastic responses, leading to broader, lasting improvements in how the brain processes pain, mood, and sensory information, contributing to enhanced quality of life [9]. 

Balancing “Fight-or-Flight” and “Rest-and-Digest” for Better Health

In our fast-paced, high-stress modern world, many people exist in a state of sympathetic dominance. Their “accelerator” is perpetually pressed down, leading to chronic stress, anxiety, and burnout. The goal of nervous system regulation is to restore balance and help the body re-engage its “brake”—the parasympathetic system. 

Spinal manipulation provides a powerful somatosensory (body-to-brain) input that can help shift this balance. Research published by the National Institutes of Health states this clearly: “Chiropractic care and spinal manipulation regulate the autonomic nervous system at peripheral level… In particular, they may activate the parasympathetic system to counterbalance the activity of the sympathetic system”[11]. This neurological shift is not just a feeling; it can be observed. A pilot study in Scientific Reports used advanced brain imaging (sLORETA) to show that a single session of spinal manipulation altered brain activity in regions involved in processing stress and sensory information, suggesting a change in central pain processing [10]. 

Reducing Inflammation Through Nervous System Regulation

A balanced nervous system is a key tool in controlling chronic inflammation. A critical anti-inflammatory mechanism in the body is known as the “cholinergic anti-inflammatory pathway.” This pathway is mediated by the vagus nerve, the primary nerve of the parasympathetic (“rest-and-digest”) system. When the vagus nerve is activated, it releases a neurotransmitter that actively inhibits the production of pro-inflammatory cytokines. 

As established by the review in Autoimmunity Reviews, the ANS plays a powerful role in modulating inflammation [5]. By stimulating the parasympathetic system, chiropractic adjustments may help enhance this natural anti-inflammatory pathway. This down-regulation of chronic, low-grade inflammation frees up the body’s resources, allowing the immune system to operate more efficiently and reducing the overall burden on the circulatory system. 

How Nervous System Balance Builds Whole-Body Resilience

A well-regulated nervous system fosters a state of homeostasis, allowing your body to adapt more effectively to any stressor it encounters, whether it’s a pathogen, a psychological worry, or a physical demand. The benefits of this balance are far-reaching. When your nervous system is regulated, you tend to experience improved sleep quality, more efficient digestion, a more stable mood, and better cognitive function. 

The 2024 review on neuroplastic responses supports this, linking chiropractic care to these broad improvements in pain, mood, sleep, and overall quality of life [9]. Each of these improvements contributes to a more resilient body. This is why nervous system regulation is the cornerstone of whole-body health. Chiropractic care can be a vital component of a “resilience toolkit” that also includes practices like mindfulness, proper nutrition, and regular exercise. 

The Posture–Immunity Connection

One of the most tangible ways we can observe the link between physical structure and systemic health is through posture. Poor posture is not merely an aesthetic concern; it is a state of chronic physical stress that can have measurable physiological consequences on your breathing, stress hormone levels, and, consequently, your immune function. 

A forward head posture or a slumped upper back (thoracic kyphosis) physically compresses the chest cavity, restricting the movement of the rib cage and the diaphragm. This has a direct impact on your body’s stress levels. A 2019 study published in Health Psychology and Behavioral Medicine directly linked an upright posture to lower cortisol levels and a more positive mood, while a slumped posture was associated with the opposite[6]. 

How Does Poor Posture Impact Breathing, Stress, and Immune Function?

The negative impact of poor posture is a three-part cascade. First, by restricting the diaphragm—your primary breathing muscle—slouching forces you into a pattern of shallow, rapid chest breathing. This inefficient breathing pattern reduces oxygen intake and is neurologically linked to activating the sympathetic “fight-or-flight” response. 

Second, as the 2019 study demonstrated, this physical stress state leads to a measurable increase in stress hormones like cortisol [6]. Third, this chronic elevation of cortisol suppresses the immune system over time, making you more susceptible to illness. Chiropractic care directly addresses this cascade at its root. Through spinal adjustments, postural correction exercises, and ergonomic advice, a chiropractor can help restore proper spinal curves, improve mobility, and retrain your body to maintain a healthier posture, thereby reducing this chronic stressor and its negative impact on immune function. 

Chiropractic Care During Cold and Flu Season

Navigating healthcare during cold and flu season requires practical, safety-focused wisdom. As a partner in your health, a responsible chiropractor prioritizes your well-being and works in concert with your primary care physician. 

Should You Go to the Chiropractor When You’re Sick?

This is a critical question with a nuanced answer rooted in safety. If you are acutely ill with a systemic infection—meaning you have symptoms like a fever, productive cough, body aches, or significant fatigue—it is best to stay home, rest, and consult your medical doctor. This is important for your own recovery and to prevent the spread of contagious illness to the clinical team and other patients. 

However, once the acute phase of an illness has passed, chiropractic care may be appropriate for related musculoskeletal issues, such as neck pain and stiffness from persistent coughing or headaches from tension. The decision to seek care should always be made in consultation with your healthcare providers. If you are unsure, call your chiropractor’s office to discuss your symptoms before coming in. 

See a medical doctor immediately if you experience red flag symptoms such as high fever, difficulty breathing, chest pain, or confusion. 

Can Chiropractic Care Help with Congestion or Sinus Pressure?

While chiropractic does not treat the underlying cold, flu, or allergy causing sinus issues, certain gentle techniques may provide significant symptomatic relief from sinus pressure and congestion. The goal of these techniques is not to cure the infection but to improve mechanical drainage. 

A chiropractor may use gentle adjustments to the upper cervical spine to improve mobility and function in the neck. They may also employ specific soft tissue methods, including manual lymphatic drainage techniques around the face, neck, and clavicles, or gentle mobilization of the facial bones. These approaches can help decrease pressure, open up sinus drainage pathways, and relieve the tension headaches that often accompany sinus congestion. This care is a complementary strategy that can work alongside standard medical advice like hydration, rest, and the use of decongestants. 

Conclusion

The winter season doesn’t have to be a time of compromised health. Your body’s resilience is built upon a foundation of well-functioning internal systems, all governed by the master control network: your nervous system. As we’ve explored, there is a plausible and evidence-supported link between the health of your spine, the regulation of your nervous system, and the efficiency of your immune and circulatory systems. 

Chiropractic care, by focusing on restoring proper spinal mechanics and optimizing nerve communication, offers a powerful way to support this foundation. Its primary influence is through nervous system regulation, which can help shift the body from a chronic “fight-or-flight” state to a “rest-and-digest” mode that fosters healing and adaptability. This shift can, in turn, help modulate inflammation, improve circulation for a more rapid immune response, and reduce the physiological stress that taxes your body’s defenses. Viewing chiropractic as a proactive, complementary strategy for optimizing your body’s innate function—rather than a “cure” for sickness—is the key to unlocking its benefits for your whole-body wellness. 

If you are ready to take a proactive, holistic approach to your health this season, schedule a consultation with a qualified Doctor of Chiropractic to discuss how a personalized care plan can help optimize your nervous system and support your overall wellness goals. At Vida Integrated Health, you’ll find a full range of services designed to support your health from all angles. This includes chiropractic care, physical therapy, acupuncture, massage therapy, and functional medicine. Each service works together to help you function at your best and build a stronger, more resilient body. Start your journey toward a healthier and more energized you today.   

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Chiropractic care is a complementary health strategy and should not be used as a primary treatment for acute illness. Always consult with your primary care physician for any health concerns, especially when you are sick. 

References 

1. Wyse, C., O’Malley, G., Coogan, A. N., McConkey, S., & Smith, D. J. (2021). Seasonal and daytime variation in multiple immune parameters in humans: Evidence from 329,261 participants of the UK Biobank cohort. iScience, 24(4), 102255. Retrieved from https://doi.org/10.1016/j.isci.2021.102255 
2. Halonen, J. I., Zanobetti, A., Sparrow, D., Vokonas, P. S., & Schwartz, J. (2010). Associations between outdoor temperature and markers of inflammation: a cohort study. Environmental Health: A Global Access Science Source, 9, 42. Retrieved from https://doi.org/10.1186/1476-069X-9-42 
3. Chow, N., Hogg-Johnson, S., Mior, S., Cancelliere, C., Injeyan, S., Teodorczyk-Injeyan, J., Cassidy, J. D., Taylor-Vaisey, A., & Côté, P. (2021). Assessment of Studies Evaluating Spinal Manipulative Therapy and Infectious Disease and Immune System Outcomes: A Systematic Review. JAMA Network Open, 4(4), e215493. Retrieved from https://doi.org/10.1001/jamanetworkopen.2021.5493 
4. Holt, K., & Russell, D. (2023). Vertebral Subluxation and Systems Biology: An Integrative Review Exploring the Salutogenic Influence of Chiropractic Care on the Neuroendocrine-Immune System. Cureus, 15(12), e50123. Retrieved from https://www.cureus.com/articles/229791-vertebral-subluxation-and-systems-biology-an-integrative-review-exploring-the-salutogenic-influence-of-chiropractic-care-on-the-neuroendocrine-immune-system 
5. Gualtierotti, R., Vetrano, S., & Zoppi, M. (2022). The Interplay between Autonomic Nervous System and Inflammation across Systemic Autoimmune Diseases. International Journal of Molecular Sciences, 23(5), 2824. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC8910153/ 
6. Shiro, Y., et al. (2019). The Influence of a Posture on the Autonomic Nervous System and Stress Hormones in Saliva. Health Psychology and Behavioral Medicine, 7(1), 100-117. Retrieved from https://www.scirp.org/journal/paperinformation?paperid=98200 
7. Kocabey, B., Karagözoğlu Coşkunsu, D., Güven, K., Ağaoğlu, M. H., & Yüce, S. (2023). Effects of Manual Versus Instrumental Spinal Manipulation on Blood Flow of the Vertebral and Internal Carotid Arteries in Participants With Chronic Nonspecific Neck Pain: A Single-Blind, Randomized Study. Journal of Chiropractic Medicine, 22(1), 1–10. Retrieved from https://doi.org/10.1016/j.jcm.2022.05.006 
8. Wirth, B., et al. (2023). Effectiveness of spinal manipulation in influencing the autonomic nervous system – a systematic review and meta-analysis. Chiropractic & Manual Therapies, 31(1), 47. Retrieved from https://www.tandfonline.com/doi/abs/10.1080/10669817.2023.2285196 
9. Haavik, H., et al. (2024). Neuroplastic Responses to Chiropractic Care: Broad Impacts on Pain, Mood, Sleep, and Quality of Life. Medicina, 60(11), 1124. Retrieved from https://www.mdpi.com/2076-3425/14/11/1124 
10. Lelic, D., et al. (2019). The effects of chiropractic spinal manipulation on central processing of tonic pain – a pilot study using standardized low-resolution brain electromagnetic tomography (sLORETA). Scientific Reports, 9, 6925. Retrieved from https://www.nature.com/articles/s41598-019-42984-3 
11. Vaglio, A., et al. (2021). Neurobiological basis of chiropractic manipulative treatment of the spine in the care of major depression. Journal of Clinical Medicine, 10(7), 1453. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC8023121/ 
12. D’Adamo, S., et al. (2019). The Effects Induced by Spinal Manipulative Therapy on the Immune and Endocrine Systems. Healthcare (Basel), 7(3), 104. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC6722922/