Light and the Nervous System: How Natural Light Resets the Vagus Nerve and Reduces Anxiety

Jun 24
Anxiety, burnout, and nervous system dysregulation are on the rise—and yet, one of the most accessible tools for restoring balance doesn’t come in a bottle or device. It comes from the sky.

The vagus nerve, the longest cranial nerve in the body, is a key regulator of the parasympathetic nervous system—the system responsible for rest, repair, and emotional regulation. While breathwork, cold exposure, and sound therapy have become popular tools for activating vagal tone, research shows that natural light—particularly full-spectrum morning sunlight—also plays a profound role in regulating the vagus nerve and restoring nervous system balance.

This article explores the connection between light, circadian rhythms, and vagal health, highlighting how sunlight exposure can act as a gentle but powerful recalibration tool for those struggling with anxiety, fatigue, and trauma-related symptoms.


If you’re feeling wired, anxious, or unable to sleep, one of the first things to assess is your light exposure.”

 – Dr. Andrew Huberman

The Vagus Nerve: The Body’s Internal Regulator

The vagus nerve branches from the brainstem down through the neck, heart, lungs, and digestive organs. It serves as the communication highway between the brain and body, regulating:

  •  Heart rate variability (HRV)
  •  Breath rate and depth
  •  Digestive processes
  •  Emotional regulation and mood
  •  Inflammatory pathways

Healthy vagal tone allows us to shift from stress responses into states of safety, calm, and connection. Poor vagal tone has been associated with anxiety, depression, PTSD, IBS, and autoimmune dysfunction.

This clear, 5‑minute video breaks down how daily light exposure can ‘flip the vagal switch’ and support calm.

Circadian Rhythm and Vagal Tone: The Light Link

Light is the primary Zeitgeber (time-giver) that entrains the circadian rhythm. Early morning sunlight stimulates the retinohypothalamic tract, which connects the retina to the suprachiasmatic nucleus (SCN)—the brain’s master clock. The SCN then orchestrates daily rhythms in hormone release, sleep-wake cycles, and autonomic nervous system balance.

Here’s how light specifically supports vagus nerve function:

  • Research shows that morning light helps sync the HPA axis, resulting in an adaptive cortisol awakening response that supports vagal function.
  • Daytime light enhances serotonin synthesis, which is a precursor to melatonin and helps modulate mood.
  • Light synchronizes autonomic rhythms, balancing sympathetic (fight/flight) and parasympathetic (rest/digest) activity via the vagus.
  • Proper circadian signaling optimizes heart rate variability (HRV)—a measurable indicator of vagal tone.

Evening exposure to artificial light, particularly blue light, can suppress melatonin, dysregulate the HPA axis, and keep the body in a state of sympathetic arousal—fueling nervous system imbalance.


Natural Light Practices for Vagus Nerve Support

Morning Sunlight Ritual (within 30 minutes of waking):
Stimulates SCN, boosts serotonin, entrains circadian rhythm, and anchors the nervous system in safety.

Grounding + Light:
Standing barefoot on earth while receiving sunlight enhances the electromagnetic coherence of the body, supporting HRV and vagal tone.

Evening Light Hygiene:
Dim lights after sunset, use amber or red bulbs, and eliminate screen use 1–2 hours before bed to protect melatonin and vagal regulation during sleep.

Red Light Therapy:
10–15 minutes directed over the chest, neck, or abdomen can stimulate mitochondrial function and calm vagal output.

Red and Near-Infrared Light: Mitochondrial Medicine for the Nervous System

Red and near-infrared (NIR) light, particularly in the 600–850 nm wavelength range, have been shown to profoundly influence nervous system function through a process known as photobiomodulation (PBM). When these wavelengths penetrate the skin, they are absorbed by cytochrome c oxidase, a key enzyme in the mitochondrial respiratory chain. This interaction stimulates ATP production, modulates reactive oxygen species, and triggers cellular signaling pathways that enhance repair and reduce inflammation.

In his comprehensive review, Dr. Michael Hamblin (2017) details how PBM enhances neuronal bioenergetics and supports synaptic plasticity, which is critical for cognitive function, mood regulation, and recovery from trauma. PBM has also been found to reduce neuroinflammation, promote the release of brain-derived neurotrophic factor (BDNF), and even aid in the repair of myelin sheaths—making it an especially promising therapy for conditions like anxiety, PTSD, and brain fog associated with chronic stress.

Emerging studies also show that transcranial or thoracic application of red/NIR light can stimulate vagal tone, improve heart rate variability (HRV), and balance autonomic nervous system output. These effects suggest that red light therapy may not only support general mitochondrial function but also facilitate neurovisceral integration—a cornerstone of the vagus nerve’s role in regulating the body’s response to stress.

Red and near-infrared (NIR) light, used in photobiomodulation therapy (PBMT), have also been shown to support nervous system recovery:

  • Increases ATP in neuronal mitochondria, improving brain energy and resilience
  • Reduces neuroinflammation, particularly in stress-sensitive regions like the amygdala
  • Supports myelin repair and synaptic plasticity, key for trauma recovery
  • Enhances vagal nerve regeneration in preclinical studies

For individuals with anxiety, trauma, or chronic dysregulation, red light therapy can serve as a non-invasive adjunct to nervous system healing, especially when applied to the neck, heart, or abdomen.

Photobiomodulation and Trauma Recovery: Light for Rewiring and Repair

Trauma—especially unresolved or chronic forms like PTSD—often leaves the nervous system stuck in patterns of sympathetic hyperarousal or dorsal vagal shutdown. Individuals in this state may experience anxiety, hypervigilance, emotional numbness, or chronic fatigue. While therapeutic modalities like somatic therapy and EMDR are gaining ground, emerging evidence suggests that red and near-infrared light therapy may offer meaningful neurophysiological support for trauma recovery.

A 2021 review by Martinu et al. examined the role of transcranial photobiomodulation (tPBM) in addressing symptoms associated with traumatic brain injury (TBI), anxiety, depression, and PTSD. Findings indicated that PBM can enhance mitochondrial function in neurons, promote regional cerebral blood flow, and reduce neuroinflammation—all of which support the restoration of emotional regulation, executive function, and autonomic balance.

Furthermore, PBM has been shown to elevate brain-derived neurotrophic factor (BDNF) and improve prefrontal cortex function, both of which are vital for integrating traumatic memories and breaking maladaptive neural loops. For those whose trauma has disrupted circadian rhythms or vagal regulation, red/NIR light—especially when used consistently over time—can gently entrain the nervous system back into a window of tolerance, enhancing the efficacy of other healing modalities.

In practice, this makes light therapy a valuable adjunct for individuals navigating trauma—not as a cure-all, but as a biological stabilizer that restores the energetic foundation needed for deeper emotional healing to take root.

Light exposure—especially morning sunlight and photobiomodulation—can gently coax the nervous system into a window of tolerance by:

  • Signaling time, structure, and orientation (safety)
  • Supporting neuroendocrine balance (cortisol/oxytocin)
  • Facilitating mitochondrial recovery in neurons
  • Encouraging healthy neuroplastic rewiring

Combined with somatic practices like breathwork, light can become a profound partner in restoring nervous system coherence.


Light as a Calming Medicine for the Soul

Our nervous system doesn’t just respond to thoughts—it responds to environmental input. And among all inputs, light may be the most foundational. By returning to natural light cycles, we regulate not only our sleep and energy—but our sense of inner safety, connection, and calm.

In an age of overstimulation, light offers a subtle but potent medicine for vagus nerve health. With each sunrise, our biology remembers: you are safe, you are alive, and healing is possible.

Trauma & Light Therapy: FAQ

Can light exposure really help with trauma and PTSD?

Yes—both natural sunlight and red/near-infrared (NIR) light therapy have been shown to support trauma recovery. Morning sunlight helps regulate circadian rhythms, boost serotonin, and signal safety to the brain. Red/NIR light therapy penetrates deeper tissues, enhancing mitochondrial energy, reducing inflammation, and supporting nervous system repair—all vital for trauma resolution.

Is it safe to use light therapy if I have complex trauma?

For most people, yes—but go gently and start small. Early morning sunlight is generally safe and grounding. With red/NIR devices, begin with low-intensity sessions (5–10 minutes) and track how your body responds. Some individuals may experience emotional releases or sleep pattern shifts as their nervous system recalibrates.

Where and how should I apply light for trauma healing?

  • Sunlight: Aim for 10–20 minutes of morning light exposure on your face and eyes (without sunglasses), and bare skin when possible.
  • Red/NIR Light: Apply to the chest (vagus nerve), neck, upper back, or forehead. Always follow product guidelines or consult a trained provider.

Combining both can enhance healing: start the day with sun, and use red light in the afternoon or evening to support repair and relaxation.

What time of day is best for light therapy in trauma recovery?

  • Morning sunlight is key for regulating cortisol rhythms, mood, and vagal tone.
  • Red/NIR light therapy can be used in the early morning to energize or in the evening to support cellular repair—just avoid overstimulation before bed.

What signs suggest light is helping my nervous system?

You may notice improved mood, deeper sleep, fewer anxiety spikes, greater emotional steadiness, or increased heart rate variability (HRV if you’re tracking). The shifts are often subtle at first, but become more consistent over time.

References

 1. Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. Norton & Company.
 2. Czeisler, C. A., & Gooley, J. J. (2007). Sleep and Circadian Rhythms in Humans. Cold Spring Harbor Symposia on Quantitative Biology.
 3. Hamblin, M. R. (2017). Mechanisms and Applications of the Anti-Inflammatory Effects of Photobiomodulation. AIMS Biophysics, 4(3), 337–361.
 4. LeGates, T. A., Fernandez, D. C., & Hattar, S. (2014). Light as a Central Modulator of Circadian Rhythms, Sleep, and Affect. Nature Reviews Neuroscience, 15(7), 443–454.
 5. Martinu, K., et al. (2021). Low-Level Light Therapy and Photobiomodulation for Traumatic Brain Injury and Stress Regulation: A Systematic Review. Frontiers in Neurology, 12.
 6. Berman, M. H., et al. (2017). Transcranial Photobiomodulation Improves Cognitive Function in Patients with Chronic Mild Traumatic Brain Injury: A Placebo-Controlled Crossover Trial. PLoS ONE, 12(4), e0176689.


Connect with me

Featured links

Get in touch

  • info@valeriechristina.com
  • valeriechristina.com
  • 612-546-1951

Dispensary

Order supplements through my Fullscript store.
Copyright © 2025
Created with