The aim of the present study was to investigate the effect of vagal tone on performance during executive and non-executive tasks, using a working memory and a sustained attention test. Reactivity to cognitive tasks was also investigated using heart rate (HR) and heart rate variability (HRV). Fifty-three male sailors from the Royal Norwegian Navy participated in this study. Inter-beat-intervals were recorded continuously for 5 min of baseline, followed by randomized presentation of a working memory test (WMT) based on Baddeley and Hitch’s research (1974) and a continuous performance test (CPT). The session ended with a 5-min recovery period. High HRV and low HRV groups were formed based on a median split of the root mean squared successive differences during baseline. The results showed that the high HRV group showed more correct responses than the low HRV group on the WMT. Furthermore, the high HRV group showed faster mean reaction time (mRT), more correct responses and less error, than the low HRV group on the CPT. Follow-up analysis revealed that this was evident only for components of the CPT where executive functions were involved. The analyses of reactivity showed a suppression of HRV and an increase in HR during presentation of cognitive tasks compared to recovery. This was evident for both groups. The present results indicated that high HRV was associated with better performance on tasks involving executive function.

Twenty patients with dental anxiety were investigated while seated in a dental chair in a dental clinic. Heart rate (HR), heart rate variability (HRV), and skin conductance level (SCL) were recorded while the patients were exposed to scenes of dental treatment as well as a Stroop attentional task. Results showed an attentional bias with longer manual reaction times (RT’s) to the incongruent compared to the congruent color words as well as the threat compared to the neutral words. Longer RT’s to the incongruent and the threat words were found in the low HRV patients compared to the high HRV patients. Furthermore, all patients showed an increase in HR during exposure and the Stroop task compared to baseline. The HRV showed a decrease during the exposure and the Stroop task compared to baseline. HR and HRV did not differ between exposure and the Stroop task. Moreover, HR and HRV did not return to baseline levels during the recovery period. The SCL showed an increase from baseline to exposure, from exposure to the Stroop task and a decrease in the recovery phase. Results showed the importance of vagal cardiac control in attentional, emotional, and physiological processes in patients suffering from dental fear.

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.

This study investigated the relation of dispositional hostility to cardiovascular reactivity during an anger-recall task and of hostility and distraction to posttask recovery in 80 healthy women (ages 18-30). Half were randomly assigned to distraction during recovery. Hostility predicted slower systolic blood pressure and preejection period during recovery. Distraction was related to faster cardiac recovery, higher high-frequency (HF) power, lower low-frequency (LF) power and LF:HF ratios, and lower state anger and rumination during recovery. These results indicate deleterious influences of hostility on cardiovascular recovery but not during anger recall. The findings also show beneficial effects of distraction in expediting cardiovascular recovery, possibly through reducing rumination and anger. (PsycINFO Database Record (c) 2016 APA, all rights reserved)

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.

Objective: 
To hypothesize that increased heart rate (HR) and decreased heart rate variability (HRV) occurs not only during stressful events but also during episodes in which stress is cognitively represented, but not necessarily present, i.e., during worry.
Methods: 
Ambulatory HR and HRV of 73 female and male teachers were recorded for 4 days, during which they reported, on an hourly basis using computerized diaries, the number and characteristics of worry episodes and stressful events. Multilevel regression models were used, controlling for biobehavioral variables.
Results: 
Compared with neutral periods, worry episodes and stressful events had independent effects on HR (2.00 beats/min and 2.75 beats/min, respectively) and HRV (−1.07ms and −1.05, respectively). Neither psychological traits nor biobehavioral variables influenced these results. Effects were most pronounced for work-related worry on HR (9.16 beats/min) and HRV (−1.19 ms), and for worry about anticipated future stress on HR (4.79 beats/min).
Conclusions: 
Worry in daily life might have substantial cardiac effects in addition to the effects of stressful events, especially in the form of work-related and anticipatory stress, the latter being a type of stress that has been largely neglected in stress research.
CV = cardiovascular;
HR = heart rate;
HRV = heart rate variability;
BP = blood pressure;
BMI = body mass index;
PSWQ = Penn State Worry Questionnaire;
WDQ = Worry Domain Questionnaire;
BDI = Beck Depression Inventory;
STAI = Spielberger Trait Anxiety;
CM = Cook-Medley hostility scale;
IHAT = Interpersonal Hostility Assessment Technique.

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.

Objectives: 
To test the hypothesize that increased heart rate (HR) and decreased heart rate variability (HRV) are not only due to concurrent stressful events and worries but also to stressors and worries occurring in the preceding hours or stressors anticipated to occur in the next hour. Worry was expected to mediate at least part of the prolonged effects of stressors.
Methods: 
Ambulatory HR and HRV of 73 teachers were recorded for 4 days, during which the participants reported occurrence and duration of worry episodes and stressful events on an hourly basis, using computerized diaries. Multilevel regression models were used, accounting for effects of several biobehavioral variables.
Results: 
Stressful events were not associated with changes in HR or HRV. However, worry episodes had effects on concurrent HR and HRV (2.55 beats/minute; −5.76 milliseconds) and HR and HRV in the succeeding hour (3.05 beats/minute; −5.80 milliseconds) and 2 hours later (1.52 beats/minute; −3.14 milliseconds). These findings were independent of emotions, physical activity, posture, and other biobehavioral factors.
Conclusion: 
Worry has effects on cardiac activity, and these effects were still visible after 2 hours. The latter finding suggests that a considerable part of prolonged activation may be induced by unconscious stress-related cognition.
CV = cardiovascular disease;
HR = heart rate;
HRV = heart rate variability;
BP = blood pressure;
BMI = body mass index;
ECG = electrocardiogram.

Background
Patients with panic disorder (PD) are known to report impaired sleep quality and symptoms of insomnia. PD is an anxiety disorder characterised by deficient physiological regulation as measured by heart rate variability (HRV), and reduced HRV, PD and insomnia have all been related to impaired inhibitory ability. The present study aimed to investigate the interrelationships between subjectively reported sleep impairment, cognitive inhibition and vagally mediated HRV in a sample characterised by variability on measures of all these constructs.
Methods
Thirty-six patients with PD with or without agoraphobia were included. Cognitive inhibition was assessed with the Color–Word Interference Test from the Delis–Kaplan Executive Function System (D-KEFS), HRV was measured using high frequency (HF) power (ms2), and subjectively reported sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI).
Results
Cognitive inhibition was related to both Sleep latency and Sleep disturbances, whereas HRV was only related to Sleep disturbances. These relationships were significant also after controlling for depression.
Limitations
Correlational design.
Conclusion
Cognitive inhibition is related to key insomnia symptoms: sleep initiation and sleep maintenance. The data supports the psychobiological inhibition model of insomnia, and extends previous findings. Possible clinical implications of these findings are discussed.

Heart rate variability (HRV) is reduced in patients who suffer from panic disorder (PD). Reduced HRV is related to hypoactivity in the prefrontal cortex (PFC), which negatively affects executive functioning. The present study assessed the relationships between vagally mediated HRV at baseline and measures of executive functioning in 36 patients with PD. Associations between these physiological and cognitive measures and panic-related variables were also investigated. HRV was measured using HF-power (ms2), and executive functions were assessed with the Wisconsin Card Sorting Test (WCST) and the Color-Word Interference Test (CWIT) from the Delis-Kaplan Executive Function System (D-KEFS). Panic-related variables comprised panic frequency, panic-related distress, and duration of PD. Performance on the neuropsychological measures correlated significantly with HRV. Both panic-related distress and duration of PD were inversely related with measures of HRV and cognitive inhibition. The current findings support the purported relationship between HRV and executive functions involving the PFC.