According to the Scientific American report, odours not only affect our mood but also change bodily functions like heart rate, and motivate our actions. One study showed that people were better at creative problem-solving when exposed to an aroma they liked.
There’s no doubt that aromas work powerfully on our conscious and subconscious minds. The smell of your beloved can cause a cascade of heart-opening love or joy; a deep relaxed feeling of being home as you gently kiss the nape of the neck, inhaling his or her smell.
Conversely, an unexpected whiff of a past or deceased love’s aftershave or perfume can trigger unresolved grief, leaving one feeling helpless and overcome with loss and sadness, swimming in a deep, undulating ocean of emotions.
Our smell mechanism – the olfactory system – is a marvel of creation. Odorants or aromatic molecules from plants and other substances enter the nostrils and stimulate tiny hairs called cilia embedded in neural tissue in the nose’s epithelium. It’s the only place in the human body where the central nervous system is exposed to direct contact with the environment. Smell is therefore a link between our brain and the outside world – which is also why airborne pollutants can have such a deleterious effect on our health.
Aromas pass into the limbic system – the area of the brain associated with strong emotions such as anger, fear and joy. The limbic lobe can directly activate the hypothalamus, or master gland, which controls production of certain hormones and neurotransmitters. The hormone serotonin reduces anxiety while producing a pleasant and euphoric sensation – which is why exposing people to pleasant smells is the reason aromatherapy sessions can have a powerful healing effect, allowing the body the opportunity to release trauma held in the cells sometimes over many years.
Hardly new, aromatherapy dates back to around 4500 BC, when the Ancient Egyptians used essential oils – aromatic plant essences – for bathing, embalming, anointing, massaging, purifying air and repelling insects. Doctor Jean Valnet, the father of modern aromatherapy, successfully used plant essences for healing wounded soldiers in WW II when there was a shortage of antibiotics. After the war he went into private practice in Paris to study their different actions and anti-infection properties. Notably, he worked on treating an isolated bacterial strain with aromatic gases instead of conventional antibiotics.
Distinguishing between good and bad or healthy and unhealthy aromas is part of our primitive survival mechanism and the reason we are able to enjoy the healthful effects of aromatherapy. In her Nobel lecture “Unraveling the Sense of Smell,” Linda B. Buck says humans can differentiate as many as 100,000 different chemical odours, which sometimes only have slight differences in their molecular structure.