Author(s): YAMAMOTO, N.1, KASHIWAGI, Y.2, HIRANO, T.5, TAKENOYA, F.3, SHINTAKU, Y.4, WADA, T.5, Institution: JAPANESE RED CROSS COLLEGE OF NURSING, Country: JAPAN, Abstract-ID: 1530

INTRODUCTION:
It was reported that high-concentration artificial carbon dioxide baths (CO2-water, CO2≥1000ppm) suppress autonomic nerve activity and promote recovery from fatigue (Yamamoto, N. et. al., 2017). In addition, the odor stimulation of aromatherapy has been shown to have stimulating and sedative effects (Takenoya, F. et. al., 2018). These combined effects may enable prompt recovery from physical and mental fatigue. Therefore, the purpose of this study was to examine the effects of a highly concentrated (>1000 ppm) artificial carbonated spring (CO2-water) and fragrance inhalation of lemongrass essential oil on fatigue and muscle function.
METHODS:
The healthy male college students (n=6) participated in this study. The subjects were randomly divided into the aroma group and the control group, and a crossover test was conducted. The aroma group was given three sprays of lemongrass essential oil (Cymbopogon flexosus, geraniol 39.66%, neral 31.83%, geraniol 6.93%) diluted to 1% on the inside of a non-woven mask, which they wore during the experiment. The subjects performed to 150 times calf raises. The Borg CR10 scale, which indicates subjective exercise intensity, was recorded every 2 minutes during the calf raises. After the calf raises, the subjects immersed their lower legs up to below the knee into CO2-water at 35 °C for 10 minutes. Subjective thermal sensation (TS) during the lower leg bath were recorded by every two minutes. Before exercise, after exercise, and after the lower leg bath, we measured general fatigue by Visual Analogue Scale (VAS) and maximal isometric plantar flexion and dorsiflexion torques. In addition, muscle soreness was recorded using the Talag scale for 7 days after the experiment. We compared the variables after the aroma group and after the control group using a paired Students t-test. The significance level was set at p < 0.05.
RESULTS:
CR10 tended to be lower in the aroma group than in the control group during the latter half of calf raises. After calf raises, VAS tended to be lower in the aroma group than in the control group. The VAS after the CO2-water lower leg bath was lower than that immediately after the exercise, and a rapid recovery was observed. Also, ankle joint torque tended to be lower in the control group after exercise and after the lower leg bath. Changes in muscle soreness were lower in the aroma group than in the control group on all days during the first week after exercise.
CONCLUSION:
In this study, subjective exercise intensity was modified by fragrance inhalation of lemongrass essential oil. In addition, muscle soreness tended to be suppressed in the aroma group. Thus, the combination of CO2-water lower leg bath and aromatic effects may improve work efficiency. These results suggest that the combination of CO2-water baths and aromatherapy can be applied not only to sports training and medical care, but also to a wide variety of work situations.