Inhalation effect of lychee-scented candles on stress and sleep quality among adults and the elderly: a pilot randomized controlled study

Abstract

[Purpose] This pilot study aims to investigate the effects of inhaling lychee-scented candles on stress and sleep quality among adults and the elderly. [Participants and Methods] Thirty participants were randomly assigned to either the control (n=15) or experimental (n=15) groups. The experimental group inhaled the scent from the lychee soy wax candle prior to going to bed for four weeks (20 minutes/session, three days/week). Perceived stress was assessed using the Suanprung Stress Test-20 (SPST-20), while sleep quality was assessed using the Thai-Pittsburgh Sleep Quality Index (Thai-PSQI). All outcomes were determined at the baseline two weeks to four weeks after scent inhalation. [Results] The results indicated significant differences in sleep quality between the two groups. The experimental group showed a statistically significant improvement in sleep quality compared to the control group. Although, there was no difference between groups, the experimental group presented significant decrease in stress as time passed whereas the opposite trend was seen for the control group. [Conclusion] This preliminary study suggests that the inhalation of lychee soy wax candles over a four-week period improved sleep quality in adults and the elderly but had no effect on reducing stress.