Effects of Long Exposures of Peppermint Aroma on Awareness in Simulated Driving

Reports show that number of driving accident is still high. Among the main the factors causing the accident is sleepiness induced by fatigue and monotonous driving task. Though there is a lack of consensus, stimulant aroma has been reported as an alternative intervention to maintain awareness. However, its long exposure effect is not known yet. This research consisted of two studies. The first study was conducted to investigate people preferences against three stimulant odors: pepermint, rosemary, and basil essential oil. The second study was carried out to investigate effects of the most preferred aroma in long exposures on awareness in simulated driving In the first study, a questionnaire was distributed to 100 participants. They were asked to rate both "liking" and "wanting" of each odor given randomly. Results of the first study indicated that the most liked and wanted odor was peppermint. However, there were no significant differences of these three aromas based on gender or ethnic group (p>0.05). Therefore, peppermint was then used in the second study. In the second study, a total of 12 participants performed simulated driving for 2 hours under three conditions: (1) without peppermint odor exposure, (2) with peppermint odor exposure only during the simulation, and (3) with the exposure for 3 consecutive nights before the simulation. During the experiment, participants' awareness was monitored using electroencephalograph (EEG), heart rate monitor (HRM), and Karolinska Sleepiness Scale (KSS). Results of this study shows that there was an increased awareness indicated during both, short and long exposure of peppermint odor, compared to no-odor condition. There was no significant difference (p>0.05) between the effect short and long exposure of peppermint odor. This study suggests possibility of using peppermint odor in maintaining awareness in driving.