Fig. 2
From: Effects of olfactory stimulation by α-pinene on autonomic nervous activity
The 30-s means and overall mean high-frequency (HF) component of heart rate variability (HRV) during olfactory stimulation by α-pinene or control. a Changes in each 30-s mean HF value over 90 s. b Overall mean HF values. Data are expressed as the mean ± standard error; N = 13; *P < 0.05 as determined using the paired t test (one sided)