The present study addressed autonomic nervous system (ANS) patterning during experimentally manipulated emotion. Film clips previously shown to induce amusement, anger, contentment, disgust, fear and sadness, in addition to a neutral control film, were presented to 34 college-aged subjects while skin conductance, blood pressure and the electrocardiogram (ECG) were recorded, as was self-reported affect. Both mean of and mean successive difference of heart period were derived from the ECG. Pattern classification analyses revealed emotion-specific autonomic patterning for all emotion conditions except disgust; all emotion conditions exhibited significant patterning using self-report. Discriminant function analysis was used to describe the location of discrete emotions within dimensional affective space using both self-report and ANS variables. Findings suggest that the dimensions of valence and activation portray the structure of self-reported emotion, but that valence is more accurately described as approach–withdrawal when applied to autonomic responses during discrete emotions. The findings provide further support for the existence of emotion-specific ANS activity, and are consistent with a hybrid discrete–dimensional model of affective space.

OBJECTIVE: This study examined the effects of exposure to job strain on independent predictors of cardiovascular disease (ambulatory blood pressure, heart rate, and heart rate variability).
METHODS: The participants comprised a homogeneous group of 159 healthy female nurses [mean age 35.9 (SD 8.5) years]. The choice of this population minimized variance attributable to gender, socioeconomic status, and work characteristics. Job demands, decision latitude, and social support were measured with the Karasek job content questionnaire, which was administered twice with an average interval of 12.2 months. The nurses’ scores for job demands and decision latitude on both occasions were used to define their job-strain category. Ambulatory blood pressure, heart rate, and heart rate variability were assessed on a workday and a day of leisure.
RESULTS: No effect on the ambulatory levels of blood pressure, heart rate, or heart rate variability was found for job strain by itself or in interaction with social support. In addition, job strain was not associated with differences in short-term or long-term physiological recovery during sleep after a workday or a day of leisure. High job demand was associated with higher systolic blood pressure at work and with higher diastolic blood pressure at work, but the latter association was found only when decision latitude was concurrently high, rather than low.
CONCLUSIONS: High job strain among young female nurses is not associated with an unfavorable ambulatory cardiovascular profile. The robust effect of job strain on male health appears to be less apparent for women.

Background— Reduced heart rate variability (HRV) is a prognostic factor for cardiac disease and cardiac mortality. Understanding the sources of individual differences in HRV may increase its diagnostic use and provide new angles for preventive therapy. To date, the contribution of genetic and environmental factors to the variance in HRV has not been investigated during prolonged periods of ambulatory monitoring in a naturalistic setting.

Methods and Results— In 772 healthy twins and singleton siblings, ambulatory ECG was recorded during 24 hours. Two time domain measures of HRV were used: the standard deviations of all normal-to-normal intervals across 5-minute segments (SDNN index) and the root mean square of successive differences between adjacent normal RR intervals (RMSSD). Multivariate genetic analyses across 4 periods of day (morning, afternoon, evening, night) yielded significant estimates for genetic contribution to the mean ambulatory SDNN index (ranging from 35% to 47%) and the mean ambulatory RMSSD (ranging from 40% to 48%).

Conclusions— Ambulatory HRV measures are highly heritable traits that can be used to support genetic association and linkage studies in their search for genetic variation influencing cardiovascular disease risk.

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.

The hypothesis that biased symptom perception toward excessive symptoms is common when relatively normal chronic patients enter symptom-relating situations, irrespective of emotional variables, was tested in 19 women with severe asthma, 18 with somatization-like characteristics, and 18 controls. Each underwent three experimental conditions: mental stress, resting, and physical exercise. Each condition included three breathing conditions: breathing normally, normal compressed air, and 5.5% CO2-enriched compressed air. Results yielded no group differences in physiological measures, e.g. elevated CO2 in exhaled air (end-tidal partial pressure of CO2, PetCO2), or lung function. Asthma patients experienced more breathlessness, and somatization-like participants more breathlessness, miscellaneous symptoms, and subjective stress than controls. Although these differences suggested acquired biased symptom perception, as it turned out, breathlessness in asthmatics was more influenced by PetCO2 and less by subjective stress compared to controls. Likewise, breathlessness in somatization-like participants was similarly influenced by PetCO2 and subjective stress compared to controls, and miscellaneous symptoms were even more influenced by PetCO2 and less by subjective stress compared to controls. It was concluded that acquired sensitivity to physiological activity associated with habitual symptoms may account for excessive symptoms in patients with chronic health problems.

The morning shift in cardiac sympatho-vagal balance seems involved in the increased risk of cardiovascular incidents at that time. To investigate the contribution of the biological clock in autonomic cardiac control, we investigated the presence of a diurnal rhythm independent of external factors, and of a circadian phase-dependent effect of moderate light in healthy volunteers. Recordings of heart rate (HR) and vagal and sympathetic cardiac tone were performed at different times over the day–night cycle during supine, awake, resting conditions, during exposure to different light intensities. The similarity between the diurnal rhythm in resting HR and that during previous constant routine conditions, demonstrated that our setup allowed accurate estimation of the endogenous circadian rhythm in HR. The present study suggests that, while a circadian rhythm in vagal cardiac tone is the main cause for the circadian rhythm in resting heart rate, the increase in sympathetic cardiac tone participates in the HR increase caused by early morning light.

Objective: To compare noninvasive measures of cardiac autonomic activity during sleep. Methods: The absolute and normalized (n.u.) high and low frequency peaks from the spectral analysis of R-R intervals (HF, LF, HFn.u., LFn.u.), LF/HF ratio, pre-ejection period (PEP) from impedance cardiography, and the autocorrelation coefficient (rRR) as illustrated in Poincaré plots were measured during night-time sleep in 9 young healthy subjects. Heart rate and blood pressure were also recorded. Results: Heart rate was significantly associated with cardiac sympathetic activity (PEP, average r=−0.46), but not with cardiac parasympathetic activity (HF, average r=−0.17). rRR was significantly associated with heart rate (average r=0.41), and LF/HF (average r=0.69), but not with PEP or HF. From NREM to REM sleep, heart rate, LFn.u., LF and rRR significantly increased, HFn.u. significantly decreased, LF/HF showed an increasing trend (P=0.07) and PEP showed a decreasing trend (P=0.06). Blood pressure and HF were highly variable without significant changes from NREM to REM sleep. Conclusions: Cardiac parasympathetic activity (HF) does not vary greatly between sleep stages. Cardiac sympathetic activity (PEP) decreases linearly during sleep. rRR and LF/HF can track sympathovagal changes during sleep, but cannot differentiate between changes in cardiac parasympathetic and sympathetic activity. The relative advantages and disadvantages of the different measures are discussed.

The role of endogenous circadian rhythmicity in autonomic cardiac reactivity to different stressors was investigated. A constant routine protocol was used with repeated exposure to a dual task and a cold pressor test. The 29 subjects were randomly divided into two groups in order to manipulate prior wakefulness. Group 1 started at 09:00 h immediately after a monitored sleep period, whereas group 2 started 12 h later. Measures of interbeat intervals (IBI), respiratory sinus arrythmia (RSA, a measure of parasympathetic activity), pre-ejection period (PEP, a measure of sympathetic activity), as well as core body temperature (CBT) were recorded continuously. Multilevel regression analyses (across-subjects) revealed significant (mainly 24 h) sinusoidal circadian variation in the response to both stressors for IBI and RSA, but not for PEP. Individual 24 + 12 h cosine fits demonstrated a relatively large interindividual variation of the phases of the IBI and RSA rhythms, as compared to that of the CBT rhythm. Sinusoidal by group interactions were found for IBI and PEP, but not for RSA. These findings were interpreted as an indication for endogenous circadian and exogenous parasympathetic (vagal) modulation of cardiac reactivity, while sympathetic reactivity is relatively unaffected by the endogenous circadian drive and mainly influenced by exogenous factors.