Is aroma overdose harmful?

Avoid overexposure to essential oil vapours as they may increase heart rate and blood pressure. Dr Kai Jen Chuang and his team from Taipei Medical University in Taiwan set up an experiment designed to simulate conditions of a typical spa, using a...

Aromatherapy can soothe stress, but breathing in too many essential oil vapours isn’t good for your health, a new study suggests.

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Dr Kai Jen Chuang and his team from Taipei Medical University in Taiwan set up an experiment designed to simulate conditions of a typical spa, using a vapouriser to dispel bergamot essential oil into the air. They recruited 100 healthy spa workers to stay in the room for two hours each during three separate visits, while researchers recorded their heart rate and blood pressure every 15 minutes. For the first hour, the subjects’ heart rates and blood pressure dropped slightly, but after 75 minutes the reverse happened — heart rates and blood pressures increased. Average increases were small, but enough to cause alarm, suggested the researchers. Chuang points out that aromatherapy oils are volatile organic compounds (VOCs), which are considered indoor air pollutants that can irritate the eyes, throat and lungs.

A study published last year had also found that spas that offer massage therapy using fragrant essential oils may have elevated levels of potentially harmful indoor air pollutants such as VOCs and ultrafine particles.