A mechanical method for changing heart rate and blood pressure

The investigation of afferent cardiovascular influences upon central nervous processes needs a methodology which allows for independent and systematic manipulation of circulatory processes. By mechanical manipulation of posture (tilt table, orthostasis) and compression of lower body parts (by anti-G-suit) reliable changes in heart rate and blood pressure can be induced. In fourty subjects (study 1) it could be shown that sustained (30 min.) changes in heart rate (e.g. orthostatic tachycardia, decrease of heart rate during compression) and mean arterial blood pressure (increase during orthostasis with and without compression) occur. Although changes in heart rate could be achieved irregardless of whether the venous "pooling" was suppressed by an air- or water-filled pressure suit, the pressor effect did differ quite considerably. In fourty-four subjects (study 2) it could be demonstrated that only by means of an water-filled suit further increases in mean arterial blood pressure could be evoked during orthostasis. Changes in hemodynamic also lead to changes in sympatho-vagal control of cardiac activity. In study 3 (ten subjects) it could be shown, that orthostasis mainly evokes alterations in sympathetic activity whereas lower body compression leads to additional increases of vagal activity and respiratory sinus arrhythmia during orthostasis.     

The relationship between resting heart rate and aggression in males is racially variant

Although resting heart rate is thought to be a generalizable risk factor for aggression, very little research has examined whether this relationship varies by race. We addressed this limitation using longitudinal data from the Pittsburgh Youth Study. Current data are from 197 men who participated in a teenage biosocial study (mean age = 15.7 years) and adult follow-up study (mean age = 32.1 years). Teenage resting heart rate interacted with race to predict teenage and adult aggression. The relationship between heart rate and aggression was significant in White, but not in Black males. To our knowledge, this is the first study to find that the relationship between resting heart rate and aggression is racially variant, suggesting that resting heart rate may not be a generalizable biomarker for conduct problems. At an intervention-level, findings could contribute to the development of more accurate risk assessment tools that take into account racial variance in risk factors.     

Task demands and the pressures of everyday life: associations between cardiovascular reactivity and work blood pressure and heart rate.

Associations between cardiovascular stress reactivity and blood pressure and heart rate recorded in everyday life were hypothesized to depend on the stressfulness of the ambulatory monitoring period relative to standardized tasks and on activity levels at the time of measurement. One hundred two female and 60 male school teachers carried out high- and low-demand tasks under standardized conditions and ambulatory monitoring during the working day. Stress ratings during the day were close to those recorded during the low-demand task. Reactions to the low-demand task were significant predictors of ambulatory blood pressure and heart rate independent of baseline, age, gender, and body mass. Associations were more consistent for ambulatory recordings taken when participants were seated than when they were standing and when the ambulatory monitoring day was considered to be as stressful as usual or more stressful than usual, and not less stressful than usual. Laboratory-field associations of cardiovascular activity depend in part on the congruence of stressfulness and physical activity level in the 2 situations.     

The relationship between vocational interest differentiation and career undecidedness

Fifty-four female and thirty male students over 20 years old were administered the Career Decision Scale and the six occupational scales of the Vocational Preference Inventory in order to test the hypothesis that indecision is negatively related to occupational interest differentiation in an adult population. Interest differentiation did not appear to be a reliable indicator of vocational undecidedness.     

Electroencephalographic and blood pressure correlates of operantly conditioned heart rate in the restrained monkey

Each of four monkeys was trained to slow its heart rate and to speed its heart rate. Mean blood pressure was positively correlated with heart rate during speeding and during slowing. These correlations increased from early training to late training for all animals during slowing; however, they did not change during speeding. High voltage in the 8–14 Hz band of the EEG was correlated negatively with heart rate; however, the correlations were insignificant or low. The correlations between EEG changes and heart rate changes increased (became more negative) during the late phase of slow training but did not change reliably during speeding training. Baseline levels in all physiological functions changed as a function of stage of training. Response patterns during escape behavior indicate dissociation of heart rate and blood pressure, whereas response patterns during avoidance behavior show correlation of heart rate and blood pressure. The findings indicate that the physiological effects of heart rate slowing and heart rate speeding are different and not merely mirror images of one another.     

The relationship between feeding rate and patch choice.

Rats in a laboratory foraging simulation searched for sequential opportunities to feed in two patches that differed in the rate at which food pellets were delivered (controlled by fixed-interval schedules) and in the size of the pellets. The profitability of feeding in each patch was calculated in terms of time (grams per minute) and in terms of effort (grams per bar press). These values were the result of the imposed fixed interval, the size of the pellets, and the rate at which the rats pressed the bar in each condition. The rats ate more food and larger meals, but not more frequent meals, at the patch offering the higher rate of food consumption, calculated as grams per minute. The relative intake at any patch was a function of the relative rate of intake during meals at that patch compared to the other patch. Rats respond to explicit manipulations of feeding time in the same manner as they respond to manipulations of feeding effort.     

The moderating role of proactive coping on the relationship between distress tolerance and elevated blood pressure

This study investigated the moderating role of proactive coping on the relationship between distress tolerance and elevated blood pressure (BP) among Nigerian adults with heart disease. Two hundred and forty hypertensive patients were recruited from the cardiology unit of a university teaching hospital (females = 56.2%%; mean age = 41.09 years, SD = 9.11 years). The participants responded to two self-reported measure including the Proactive Coping Inventory (PCI) and the Distress Tolerance Scale (DTS). Following moderated regression analysis, the results showed that proactive coping moderated the relationship between distress tolerance and elevated BP. The slope of the moderation analysis indicated that the relationship between distress tolerance and mean artery pressure was significantly higher for individuals with low proactive coping, as compared to individuals with higher proactive coping. Unlike reactive ways of coping, which addressed already existing stress, interventions aimed at increasing peoples’ proactive coping could be more efficacious in the management of people with high BP.     

The relationship between Holland's SDS differentiation scale and psychological adjustment

The study examined the relationship between Holland's SDS differentiation scales and indices of psychological adjustment on the MMPI. The independent variables were: degree of differentiation as calculated with an Iachan Index, and level of differentiation derived from averaging the six SDS summary profile scores. Two indices of the dependent variable, psychological adjustment, were used: the ego-strength score and the average elevation of eight clinical scales on the MMPI. Fifty-one subjects were recruited. Two multiple regression. analyses revealed a nonsignificant R² of 0.01. The results indicated that the SDS career interest differentiation scales were not related to the MMPI indices, and do not appear useful in predicting degree of psychological adjustment. This finding challenges Holland's theoretical contention that individuals who are undifferentiated may be in need of personal counseling. A second finding was the successful use of the SDS with residential psychiatric patients.     

Smoking, caffeine, and stress: effects on blood pressure and heart rate in male and female college students

This study examined the independent and joint effects of cigarette smoking and caffeine consumption on blood pressure (BP) and heart rate (HR) reactions to stress in male and female college students. Following an initial physiological baseline, participants received one of four experimental treatments (paced smoking, caffeine, smoking plus caffeine, or neither) and had BP and HR measured before, during, and after two stressful tasks. The results revealed that, compared with the control condition, caffeine ingestion enhanced the magnitude of stress-induced systolic BP and HR reactions. Smoking combined additively with stress, and the joint effect of smoking and caffeine was no greater than either taken alone. Males and females were generally similar in their BP and HR responses to smoking, caffeine, and stress. Inconsistencies with previous research and possible physiological mechanisms underlying the observed effects are discussed.     

Ambulatory blood pressure and heart rate in healthy male paramedics during a workday and a nonworkday.

Compared ambulatory blood pressure (BP) and heart rate (HR) in 30 paramedics during a 24-hr workday and a 24-hr nonworkday. During the 24-hr period as a whole, there were no BP differences between the workday and the nonworkday, but HR was higher during the nonworkday than during the workday. Systolic BP (SBP) recorded in the ambulance on the workday was elevated 9.8 mm Hg, compared to SBP recorded in a car on the nonworkday; it was also 7.2 mm Hg higher at the scene of an accident and at the hospital than during nonworkday activities. Ratings of moods in diaries indicated that paramedics felt more unhappiness, stress, and sadness and less feelings of pleasantness at work than at home. Rather than being elevated for the entire 24-hr period, work BP seemed to reflect the relatively high stress associated with specific situations in the work of a paramedic.     

Time-Share SKED acquisition of analog data: Blood pressure and heart rate

A computer program records, within the framework of the SKED minicomputer operating system, blood pressure and heart rate data in behavioral experiments. By repetitive (500-Hz) analog-to-digital conversions of a blood pressure waveform, the program finds and stores successive-beat systolic and diastolic pressures, and intersystolic intervals. SKED initiates and terminates blood pressure recording periods, and controls all experimental procedures. The program is currently operational, servicing four independent stations simultaneously, with sufficient computer operating time remaining to service low-priority background programs.     

Blood flow,blood pressure and heart rate changes accompanying hind leg flexion in conditional and unconditional reflexes

Results

During flexion of the hind leg to US or CS, as well as during spontaneous lifting of the leg, the blood flow in the appropriate femoral artery suddenly increases for 10–14 seconds, systemic blood pressure shows transient decrease, while heart rate and respiratory movements are accelerated. To perform one flexion and subsequent extension about 7 ml extra blood flow is necessary during UR and 5 ml during CR. During acute extinction of the CR the described vegetative changes become less and less, parallel with the gradual decrease of flexor movement of the hind leg. The sequence of extinction of the individual measured parameters was as follows: flexion, blood pressure, blood flow, heart rate, and lastly, respiration. In the mechanism of the vegetative changes accompanying the conditional hind leg flexion three main components are involved: (1) muscular-visceral reflexes originating from different receptors of the contracting muscles, (2) the emotional changes, and (3) the conditional component as a separate conditional reflex for each measured parameter. Principles underlying the formation of conditional reflexes are discussed under the headings ofschizokinesis, peripheral andcentral stimulations.Organ responsibility is the basis for the formation of the conditional reflex.     

Associations between heart rate,perceived heart rate,and anxiety during acute psychological stress

ABSTRACT

Background: Acute psychological stress elicits increases in heart rate (HR) and anxiety. Theories propose associations between HR, perceived HR, and anxiety during stress. However, anxiety is often measured as a unidimensional construct which limits a comprehensive understanding of these relationships.

Objectives: This research explored whether HR reactivity or perceived HR change was more closely associated with cognitive and somatic anxiety during acute psychological stress.

Design: Two laboratory-based studies were conducted.

Methods: In a single laboratory session, healthy male (N?=?71; study 1) and female (N?=?70; study 2) university students completed three laboratory psychological stress tasks (counterbalanced), each with a preceding baseline. Heart rate, perceived HR change, and cognitive and somatic anxiety intensity and interpretation of anxiety symptoms were assessed immediately following each task. Data were aggregated across tasks.

Results: Actual HR change was unrelated to anxiety intensity, but was associated with more debilitative interpretations of anxiety (study 2). Perceptions of HR change were consistently associated with greater intensity of cognitive (study 1) and somatic (study 1 and 2) anxiety.

Conclusions: Perceived HR rather than actual HR is more closely associated with anxiety intensity during psychological stress. The findings have implications for stress management and the clinical treatment of anxiety symptoms.     

The law of effect and avoidance: a quantitative relationship between response rate and shock-frequency reduction

Two experiments were conducted to investigate the quantitative relationship between response rate and reinforcement frequency in single and multiple variable-interval avoidance schedules. Responses cancelled delivery of shocks that were scheduled by variable-interval schedules. When shock-frequency reduction was taken as the measure of reinforcement, the relationship between response rate and reinforcement frequency on single variable-interval avoidance schedules was accurately described by Herrnstein's (1970) equation for responding on single variable-interval schedules of positive reinforcement. On multiple variable-interval avoidance schedules with brief components, asymptotic relative response rate matched relative shock-frequency reduction. The results suggest that many interactions between response rates and shock-frequency reduction in avoidance can be understood within the framework of the generalized matching relation, as applied by Herrnstein (1970) to positive reinforcement.