Heart rate and heart rate variability in school dogs

The aim of this study was to examine whether the canine stress level was elevated during animal-assisted education by means of the Polar monitor V800 (Polar Electro Oy, Kempele, Finland), which recorded heart rate (HR) and heart rate variability (HRV). At 54 Bavarian schools with one working dog each, we attended one class for a single or double session. The dog was videotaped for subsequent behavior analysis, and real-time measurements of the RR intervals were transmitted by the Polar device to the data logger attached to the dog's collar. On average, the mean HR per dog was 87 +/- standard deviation 19 beats per minute (bpm). When the dogs were grouped according to the behavior analysis, i.e., scores based on the occurrence of specified displacement behavior / appeasement behavior / signs of stress, inter alia, the "problematic " dogs (n = 25) showed significantly increased mean HR values compared to the "innocuous " dogs (n = 22). The highest mean HR values were recorded in the subgroup of "problematic " dogs during the first 10 min of the classes (107 +/- 29 bpm, vs. "innocuous " dogs: 90 +/- 22 bpm, p < 0.05). Moreover, HR and HRV were to be measured at rest for 5 min. The mean HR at rest was significantly reduced. With respect to HRV data, it turned out that only 18 dogs showed an artifact rate <= 5% and were thus suitable for analysis. Consequently, we performed a range of exploratory analyses on the one hand to examine this subgroup of dogs, on the other hand to quantify the differences in HRV parameters and to compare certain canine features among the various rates of artifacts. The HR values were in line with the behavior analysis. This was also supported by the exploration of the subgroup with an artifact rate < 5%. In conclusion, cardiac monitoring confirmed that the dogs classified as "problematic " were more stressed than the "innocuous " dogs. This study additionally provided insights into outliers in HRV data, so-called artifacts, underlining the need for standardized conditions.