Aromatherapy, which involves Inhaling the vapors from essential oils, may be beneficial for short periods, but could harm the heart if done for too long, a new study from Taiwan suggests.
In the study, 100 spa workers in Taipei sat in a room and breathed in the vapors of bergamot oil — a concentrated, citrusy extract — for two hours, while researchers measured their blood pressure and heart rate, as well as the level of volatile organic compounds (VOCs) in the air. VOCs are substances, including essential oils, which easily evaporate at room temperature.
During the first hour, the workers' blood pressure and heart rates went down. After 45 minutes, the average systolic blood pressure measurement had dropped by 2.10 mmHg, and the heart rate by 2.21 beats per minute. This finding agrees with some previous research showing essential oils relieve stress.
However, after 120 minutes, the researchers saw the opposite effect. Systolic blood pressure not only returned to the baseline level, it had risen by about 2.19 mmHg, and the heart rate was 1.70 beats per minute higher than at baseline. [See 7 Ways to Reduce Job Stress.]
"These findings suggest that overexposure to essential oil might be harmful to cardiovascular health," the researchers wrote in the Nov. 29 issue of the European Journal of Preventive Cardiology.
Previous studies have linked VOCs with an increased risk of asthma, as well as death from cardiovascular disease. Breathing these compounds may increase inflammation in the body, and alter nervous system functioning, which could then affect heart health, the researchers said.
However, further studies are needed to confirm the new results. While elevated blood pressure and heart rate are markers for cardiovascular disease, it's not clear whether small, short-term fluctuations in these measures could lead to heart problems, the researchers said. In addition, because the researchers measured total VOC levels, other compounds in the air besides those from the oil vapor itself could have influenced the results.
The finding "brings to light that more isn’t better all the time," said Dr. Suzanne Steinbaum, a preventive cardiologist at Lenox Hill Hospital in New York City, who was not involved in the study. While the findings are preliminary, it would be concerning if the elevated heart rate and blood pressure seen in the study were chronic, Steinbaum said.
Pass it on: Aromatherapy may increase blood pressure and heart rate if used for too long.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.