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Ambulatory monitoring of cardiovascular responses during behavioral modification of an aggressive dog

Previous work from our lab has used the Dutch Ambulatory Monitoring System (AMS) to assess the cardiovascular responses and motility of large free-ranging species (e.g. horses). To further examine the utility of using the AMS with non-humans, a study investigating the heart rate (HR) and heart period variability (HRV) of a large canine undergoing behavioral modification therapy was undertaken. This treatment emulated a restraint and tactile pressure technique that has previously been used in horses. Cardiovascular responses and motility were continuously measured pre-treatment (exposure to a stimulus dog), during treatment (in-box), and post-treatment. The treatment consisted of placing the dog in a 110 cm (long) by 45 cm (wide) by 102 cm (height) wooden box that only covered the animals’ torso and legs and allowed the head to be free. Once the dog was in the box, the body was covered with a lightweight material (grain product) to effect restraint and tactile pressure, which was followed by a repeat exposure to the stimulus animal. Results indicated decreased heart rate and an increased HRV during the intervention as compared to baseline with indices of motility changing in the expected directions. Estimates of respiratory frequency derived from the autoregressive spectral analysis indicated changes in respiration did not account for the cardiovascular effects. In conclusion, tactile pressure and restraint may be an important tool for behavioral modification in both humans and animals, and the AMS is a useful tool for collecting cardiovascular data on a variety of species in a great many contexts.

Alexithymia predicts attenuated autonomic reactivity, but prolonged recovery to anger recall in young women

Alexithymia has been prospectively associated with all-cause mortality and with cardiovascular morbidity. Here, stress-induced autonomic reactivity and recovery were examined as potential pathways linking alexithymia to cardiovascular disease. The relation of alexithymia to blood pressure, heart rate, and other cardiovascular parameters derived from impedance cardiography (N=80) and heart rate variability (N=40) was evaluated during rest, an anger recall task and recovery in women (ages 18–30). During anger recall, alexithymia was associated with significantly attenuated heart rate and stroke index reactivity, greater low frequency power, and with marginally dampened blood pressure and high frequency power reactivity. Overall, this response pattern suggests blunted sympathetic activation and diminished vagal withdrawal. Alexithymia was also related to slower diastolic blood pressure and quicker preejection period recovery implying abbreviated sympathetic arousal and possibly greater vagal modulation. These results impart some evidence for the hypoarousal model of alexithymia during reactivity, but the hyperarousal model during recovery. Autonomic dysregulation during and following acute emotional stress is suggested as a possible physiological pathway connecting alexithymia to cardiovascular disease.

Effects of the physical work environment on physiological measures of stress

Aims In this study we investigated the effects of the physical work environment on two physiological measures of the stress response.Methods and results Circadian variations in vagally mediated heart rate variability (HRV) and the morning rise in cortisol were evaluated in 60 participants working in a government building either in a traditional (individual offices and old cubicles; n= 40) or a modern workspace (individualized cubicles with improved views and lighting; n= 20). Results revealed significant linear (B = 1.03; confidence interval: 1.05 to 1.01, P [ 0.05) and quadratic (B = 1.001; confidence interval: 1.00041.002, P [ 0.05) trends by office type interactions for indices of vagally mediated HRV. Individuals in the old office space had flatter slopes and thus less circadian variation including less HRV at night, and a larger rise in cortisol upon awakening compared with those in the new office space.Conclusion These results indicate that physical features of the work environment may affect two aspects of the physiological stress response: circadian variations in HRV and the morning rise in cortisol. These findings have important social, economic, and public health implications for work environment risk factors on health.