Abstract
To investigate the effects of lavender oil aroma on the excitatory state of spinal motor neurons, we performed F-wave measurements as an index for testing muscle tone in the upper extremity. We conducted two experiments. In experiment 1, the effects of one drop (0.05ml) of lavender oil were studied in 18 healthy volunteers, whereas in experiment 2, the effects of three drops (0.15ml) of lavender oil were studied in 26 healthy volunteers. For each experiment, a control group of 9 healthy volunteers was used for comparison. Subjects wore masks and assumed a supine position. Lavender oil was added to a tissue in a freezer bag, and the strength of the aroma was measured. The freezer bag was inserted into the mask worn by subjects who were asked to breathe in the aroma of the lavender oil for 2 min. Persistence, latency, and F/M amplitude ratio were recorded from the thenar muscles of the left upper extremity before baseline, during (0 and 1 min), and after (5, 10, and 15 min) lavender oil inhalation. After lavender oil inhalation, excitability of spinal motor neurons that innervate the upper extremities decreased. Furthermore, inhalation of three drops of lavender oil increased excitability of the spinal neurons in subjects who had no previous experience of lavender inhalation.
