Effects of Mentha Piperita Essential Oil Uptake or Inhalation on Heart Rate Variability and Cardiopulmonary Regulation during Exercise

This study compares the effects of the uptake or inhalation of 50uL Mentha piperita (MP) essential oil for 10 days on heart rate variability (HRV) and cardiopulmonary regulation during various exercise intensities. Forty-eight healthy male subjects were randomly assigned to MP uptake (MPU; n=16), MP inhalation (MPI; n=16), and control group (C; n=16). All participants were measured resting HRV, respiratory, cardiovascular, and metabolic parameters during aerobic, anaerobic, and graded exercise tests (GXT) before and after treatment. There were significant increases in the low-frequency area (LFa; 1.8±0.1 vs 2.2±0.2 ms2), the ratio of low frequency to respiration frequency area (LFa/RFa; 0.9±0.1 vs 1.3±0.1) at resting and carbon dioxide production (VCO2; 41.2±4.0 vs 49.2±6.8 mL/min-1/kg-1), ventilation per minute (VE; 80.2±4.3 vs 97.5±5.5 L/min-1), and respiratory rate (RR; 38.2±1.9 to 44.3±2.1 breath/min-1) in an anaerobic test following MPU intervention. In GXT, maximal carbon dioxide production (VCO2max; 51.9±3.5 to 59.1±6.4 mL/min-1/kg-1), maximal ventilation per minute (VEmax; 126.4±6.5 to 138.4±5.4 L/min-1) and maximal respiratory rate (RRmax; 52.7±3.6 to 60.1±2.3 breath/min-1) significantly increased in MPU. The correlations of ΔLFa with ΔVCO2max, ΔVEmax, and ΔRRmax in the MPU group were significant. Continuous uptake or inhalation of 50uL MP oil for 10 days does not improve aerobic capacity and maximal exercise performance, but 10 days’ uptake of MP essential oil increased sympathetic activity at rest and may relate to respiratory regulation under high-intensity exercise.