It is well known that the aroma of essential oils can have an impact on the human nervous system. Through the sense of smell, the aroma quickly reaches the brain, allowing the nervous system to regulate the functioning of vital processes and senses, promoting a state of balance in the body. It can also generate a sense of tranquility or pleasure, leading to emotional healing.
The human nervous system can be divided into two parts: the central nervous system, which consists of the brain and spinal cord and controls our behavior, thinking, and memory; and the peripheral nervous system, which includes the autonomic nervous system and somatic nervous system.
The somatic nervous system is associated with motor and sensory nerves, while the autonomic nervous system regulates our bodily functions such as respiration and heartbeat autonomously, without conscious control. It maintains our basic life activities, including heartbeat, respiration, sleep, as well as functions like blood circulation, body temperature, digestion, endocrine system, immune system, and metabolism.
The autonomic nervous system is further divided into two parts: the sympathetic nervous system is activated when the body is engaged in activities, feeling stressed, or under pressure. It is responsible for excitement, increasing heart rate, and respiration. On the other hand, the parasympathetic nervous system starts working when the body is in a resting, relaxed, or sleep state. It helps us calm down, slows down heart rate and respiration, and allows us to have restful sleep.
Image source: Internet
The autonomic nervous system functions with the cooperation of the sympathetic and parasympathetic nervous systems. When the sympathetic nervous system is healthy and functioning well, it transitions smoothly to the parasympathetic nervous system. This allows us to enter a state of deep and restful sleep at night and naturally return to the sympathetic nervous system in the morning, feeling energized. This creates a positive cycle of regulation.
When the autonomic nervous system is imbalanced, it can lead to various discomforts such as insomnia, weakened immune system, headaches, sensitivity to light, temporomandibular joint disorder, tension headaches, pain in the shoulders, neck, and back, rapid heartbeat, chronic fatigue syndrome, abnormal blood pressure, and reproductive dysfunction. The overall state of health deteriorates. An imbalanced autonomic nervous system affects the body's metabolism, digestion, endocrine balance, and sleep, resulting in accelerated aging on a physical level and anxiety, depression, and insomnia on a mental level.
Image source: Internet
【The Influence of Essential Oils on the Nervous System through the Sense of Smell】
Essential oils are commonly used in incense, inhalation, massage, or in combination with skincare products. In each method of use, essential oils act on the human body through the "olfactory system." The diffused fragrance in the space primarily serves as a mental therapy, improving negative moods such as depression, negativity, and discouragement. Inhalation can be used to treat different conditions, such as relieving high blood pressure and respiratory diseases.
▎The Influence of Smell on the Nervous System
Smell is one of our five senses and allows us to detect and identify odor molecules in the air. The olfactory epithelium in the nose contains millions of chemical receptors that detect odors. When we inhale, the chemical substances in the air dissolve in mucus. Odor receptor neurons in the olfactory epithelium detect these odors and transmit signals to the olfactory bulb. These signals are then sent along the olfactory pathway to the olfactory cortex in the brain, where the signals are processed.
The olfactory cortex is crucial for processing and perceiving smells. It is located in the frontal lobe of the brain and is responsible for organizing sensory input. The olfactory cortex is also part of the limbic system, which is involved in our emotions, survival instincts, and the process of memory formation. It is connected to other limbic system structures such as the amygdala, hippocampus, and hypothalamus. The amygdala is involved in forming emotional responses, especially fear responses, the hippocampus indexes and stores memories, and the hypothalamus regulates emotional responses and influences our autonomic nervous system and endocrine system.
The connection between our sense of smell and emotions is different from other senses. The neural pathway of the olfactory system is directly linked to the brain structures of the limbic system. Therefore, smell can evoke specific memories associated with odors, trigger positive and negative emotions, and also influence our behavior. It serves as a bridge between sensory stimuli (such as smell) and our memories and emotions within the limbic system.
Image Source：Walliczek-Dworschak, Ute, and Thomas Hummel., 2017
▎The Influence of Essential Oils on the Nervous System
Through the process of inhaling essential oils, natural plant oils such as rose, ylang-ylang, bergamot, and frankincense have a balancing effect on our autonomic nervous system. For example, essential oils like rose and ylang-ylang can help increase serotonin and dopamine levels, which can alleviate depression, promote happiness, and enhance a sense of well-being. They can also affect the adrenal glands through the pathway of the hypothalamus and influence the regulation of cortisol, the stress hormone, helping to cope with life stress while avoiding an excessive accumulation of stress hormones that can lead to obesity. Some essential oils can also affect the digestive system through the vagus nerve, the tenth cranial nerve, helping to maintain a healthy balance. Cinnamon essential oil, for instance, can relieve anxiety by inhibiting the NF-kB protein. From this, it can be seen that essential oils regulate the nervous system through multifaceted mechanisms to achieve balance.
Image Source：Lizarraga‐Valderrama, Lorena R., 2021
▎Open Access to Experimental Data
By comparing the states of individuals during running exercises (activation of the sympathetic nervous system) after observing and comparing "no inhalation of essential oils," "inhalation of single essential oils," and "inhalation of blended essential oils," it was found that the "no inhalation of essential oils" group showed relatively high activation of the sympathetic nervous system and low activation of the parasympathetic nervous system. The groups that inhaled sandalwood essential oil and the group that inhaled a blend of sandalwood and lavender essential oils showed a significant decrease in sympathetic nervous system activity and an increase in parasympathetic nervous system activity. The effect was more pronounced in the group that inhaled the blend of sandalwood and lavender essential oils.
Image source: Internet
From the data obtained from the single essential oils, it was observed that some essential oils have the effect of stimulating the sympathetic nervous system or activating the parasympathetic nervous system, but the effects of blended essential oils were more pronounced. The ratios of essential oil blends require numerous experiments conducted by aromatherapists, experts in natural product chemistry, and researchers to achieve the optimal proportions and maximize the effects.
Image source: Internet
Beyond the commercial interests of our brand, Pure Truth aims to promote academic development through scientific experiments and data analysis. We strive to find the golden ratio that can balance the autonomic nervous system, leading to further advancements in the field of neuroscience and achieving the goal of holistic well-being.
 Walliczek-Dworschak, Ute, and Thomas Hummel., 2017
 Lizarraga‐Valderrama, Lorena R., 2021
Effect of aromatherapy on autonomic nervous system regulation with treadmill exercise-induced stress among adolescents,Pin-Hsuan Lin,Yuan-ping Lin,Kai-Li Chen,Shang-yu Yang,Yin-Hwa Shin,Po-Yu Wang Published:April 13,2021
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