The Vagus Nerve & Scent

It seems every other wellness magazine or blog is talking about the vagus nerve or emotional resilience so I have dedicated this months blog to how to use essential oils to stimulate the parasympathetic system (part of the central nervous system that relaxes the body after periods of stress or danger.)

In clinical aromatherapy, we often talk about “calming,” “grounding,” or “supporting the nervous system.” But what does that really mean in physiological terms? One pathway that continues to spark both research interest and clinical curiosity is the vagus nerve—and how scent, via inhalation, may influence parasympathetic activity.

The vagus nerve is the primary nerve of the parasympathetic nervous system. It plays a key role in what we often call the “rest and digest” response, influencing: Heart rate and heart rate variability, Respiratory patterns, Gastrointestinal function and emotional regulation and stress recovery.

From a clinical perspective, higher parasympathetic tone is generally associated with improved resilience to stress, better emotional regulation, and more efficient recovery after activation.

Unlike most sensory information, olfactory signals bypass the thalamus and travel directly to the limbic system, including structures involved in emotion, memory, and autonomic regulation. This is why aromas can invoke an instant reaction or memory.

Research suggests that certain aromatic compounds may be associated with measurable shifts toward parasympathetic dominance, often observed through changes in heart rate, heart rate variability, or subjective relaxation markers.

While no research proves essential oil “stimulates the vagus nerve” directly, some are more frequently studied or used for nervous system support via inhalation or topical application within treatments.

Lavender (Lavandula angustifolia) is well known for sleep promotion and its ability to help a person relax. Many people enjoy the scent and the linalool content helps calm the CNS system. A randomized controlled trial in older adults found that inhalation aromatherapy with lavender significantly reduced symptoms of anxiety, stress, and depression compared with control (distilled water) after nightly inhalation for 30 days.

Bergamot (Citrus bergamia) has an uplifting scent and like many of the citrus oils it has been shown to help with mood regulation. With bergamot being chemically made up of esters it balances emotions, induces calmness, and aids in sleep.

Clinical studies suggest that inhaling lavender and bergamot essential oils can be associated with reductions in anxiety and increases in parasympathetic markers like heart rate variability in healthy adults.

In controlled human research, ylang-ylang (Cananga odorata) oil has been shown to reduce blood pressure and pulse rate, which are objective markers often associated with reduced stress and nervous system arousal, and participants reported feeling more calm and relaxed compared with controls. These effects suggest a gentle shift away from sympathetic “fight or flight” activity toward a more relaxed state. In clinical practice, ylang ylang is frequently experienced as soothing rather than sedating, making it a useful option for individuals who feel tense, overstimulated, or emotionally frayed.

References:

Ebrahimi H, Mardani A, Basirinezhad MH, Hamidzadeh A, Eskandari F. The effects of Lavender and Chamomile essential oil inhalation aromatherapy on depression, anxiety and stress in older community-dwelling people: A randomized controlled trial. Explore (NY). 2022 May-Jun;18(3):272-278. doi: 10.1016/j.explore.2020.12.012. Epub 2021 Jan 9. PMID: 33454232.

Hongratanaworakit T, Buchbauer G. Relaxing effect of ylang ylang oil on humans after transdermal absorption. Phytother Res. 2006 Sep;20(9):758-63. doi: 10.1002/ptr.1950. PMID: 16807875.