Aromatic essential oils used in spas and homes to provide a sense of relaxation and well-being may have a downside when people are exposed for more than an hour, a new study suggests.

Researchers in Taiwan found 100 healthy spa workers exposed to the vapour of bergamot oil for up to one hour showed reduced blood pressure and heart rate. But after an hour, blood pressure and heart rate went up.

"Prolonged exposure for longer than one hour to essential oils may be harmful to cardiovascular health among spa workers," the study's authors concluded in the European Journal of Preventative Cardiology."

CBC's Kim Brunhuber talks to spa workers and a chemist about the benefits and dangers of aromatherapy.