Effects of Aromas on Autonomic Nervous Activity of Car Drivers After the Alertness Impairment

Abstract

The effects on autonomic nervous activity were investigated by supplying aromas to drivers whose alertness was impaired. α-pinene and limonene were compared with no-aroma control in a driving simulator. In the limonene-supply condition, autonomic indices suggested that mental tension might have been sustained, and the increase in the variance of respiratory frequency could be associated with maintained alertness. Physiological indices in the α-pinene condition showed the activation of sympathetic nervous activity, suggesting an enhancement in drivers’ efforts to maintain alertness. This study showed that supplying aroma might be effective in improving driver alertness.