The ECG (from both baseline and stimuli presentation) was calculated into RR intervals in the software TeleVet 100 version 5.1 beta.

The RR intervals were first re-calculated into HR (thought to be representative of both SNS and PNS). After this, the RR intervals were imported into the software Kubios HRV Analysis for a spectral analysis.

From the spectral analysis, three HRV parameters were extracted.

1. RMSSD (thought to be representative of PNS).
2. HF power (thought to be representative of PNS).
3. LF/HF ratio (thought to be representative of SNS).

The HR data (both baseline and stimuli presentation) were analysed with a General Linear Model (GLM).

The HRV data (both baseline and stimuli presentation) were analysed with the GENMOD procedure.

The level of significance was set at P<0.05.