Differences In Heart Rate Responses Research Articles

Abstract 115: Primary Hyperadrenergic Postural Tachycardia Syndrome. Evidence From Sympathetic Nerve Recordings

Postural tachycardia syndrome (POTS) is a chronic disabling condition with excessive upright tachycardia and symptoms due to enhanced sympathetic activity in otherwise healthy young individuals. Because it is not clear if sympathetic activation is a primary phenomenon, or an appropriate compensatory response to hypovolemia, deconditioning or partial neuropathy, we analyzed resting supine muscle sympathetic nerve activity (MSNA) in 38 female POTS patients (mean±SD, age 32.1±9.1, BMI 22.7±5.4). MSNA showed a wide range of burst rate (19.7±12.1 bursts/min, range 1.2 to 54, 95% CI: 15.7 to 23.6). We compared the 1 st and 4 th Quartiles of 28 MSNA records (MSNA_Q1: < 7.3; MSNA_Q4: > 23.4 bursts/min) to determine if resting MSNA is related to heart rate (HR) or blood pressure (BP) responses to orthostatic challenge and the Valsalva maneuver (2-way ANOVA with post-hoc tests). Upright HR was inappropriately high in both groups (MSNA_Q1: 120±19 vs. MSNA_Q4: 110±20 bpm, NS), but the MSNA_Q4 group had higher upright diastolic BP than MSNA_Q1 (81±12 vs. 62±8 mmHg, P<0.01). Similarly, there were no differences in HR response to the Valsalva maneuver between groups, but systolic and diastolic BP were higher during late phase 2 in MSNA_Q4 (p<0.05), and this was preceded by higher MSNA spike rate (44.3±16.3 vs. 81.2 ±25 maximal spikes/secs per beat, p<0.01) during early phase 2 of Valsalva maneuver. The greater BP responses, but comparable HR responses, to posture and Valsalva challenges provide evidence that the subset of POTS patients with higher resting MSNA have a primary sympathetic activation. These patients might benefit from sympatholytic therapy in contrast to other POTS patients with low or absent resting MSNA.

Comparison of Gender Differences in Heart Rate Response during Submaximal Exercise in Speed Skating

이 연구는 남녀 엘리트 스피드 스케이트 선수를 대상으로 안정시 심박수, 그리고 최대강도의 70%의 훈련 중 심박수와 회복기 심박수를 비교하는데 목적이 있다. 이 연구에서 남자 7명, 그리고 여자 6명의 엘리트 스피드 스케이트 선수가 참여하였으며, 안정시 심박수는 1회를 측정하였으며, 훈련 중 총 10 구간, 그리고 회복기 총 6 구간의 심박수를 10초 단위로 측정하여 다음과 같은 결과를 획득하였다. 안정시 심박수는 성별에 따라 유의한 차이가 없었다. 또한 각 시기별 훈련 중 심박수와 심박수증가율도 유의한 차이가 없었으며, 회복시 심박수와 심박수 감소율도 유의한 차이가 없었다. 이와 같은 결과는 남녀 엘리트 스피드 스케이트선수에서의 안정시, 운동시 그리고 회복시 심박수 반응이 유사하다는 것을 의미한다.

Exploring Synchronicity in the Heart Rates of Familiar and Unfamiliar Pairs of Horses and Humans Undertaking an In-Hand Task

ABSTRACTPhysiological responses that occur in horses and humans during their interactions, on the ground and during ridden work, have been investigated in a number of studies with some conflicting results. These suggest that in some situations emotional state may be transferred from humans to horses and that there is the potential for the heart rates of horse–human pairs to become synchronized during ridden work. Here we explore the effect of familiarity on the physiological responses of horse–human pairs completing a task in-hand, using heart rate as an indicator for emotional state. We investigated differences in heart rate response between familiar and unfamiliar pairings and the possibility of heart rate synchronization within each pair. Complete sets of horse and human heart rate data were available for 17 horses. We found a significant order affect, with higher horse heart rates seen the first time around the course regardless of whether a familiar or unfamiliar handler was leading (Wilcoxon test: Z=–2.67, p<0.05). However, despite this, the horses’ mean heart rates for each course were significantly higher with the unfamiliar handler than with the familiar handler (Wilcoxon test: Z=–4.46, p<0.001). In contrast, human heart rates were higher when paired with a familiar horse compared with an unfamiliar horse (Mann-Whitney U test: Z=–5.08, p<0.001). Significant correlations between horse and human heart rates were seen in three familiar pairings and two unfamiliar pairings. Our findings indicate that the relationship between horse and human heart rates during interactions is not straightforward or consistent between horses and humans, and is likely to depend on a number of factors such as experience of the test situation. Although the lower heart rates seen in horses being led by their familiar handler suggest that they are more relaxed with someone they know, this could not be said for the human partner.

Sex‐Specific Heart Rate Responses to Apneic Manipulations in Young Healthy Subjects

Contributions of lung stretch and chemoreflex stimulation to heart rate (HR) responses to apnea have not been elucidated independently in men and women. We tested the hypothesis that HR responses to apnea would be exaggerated in men relative to women. Relative changes in HR (ECG) were analyzed during 4 maximal apneic maneuvers: 1) end‐inspiratory (INSP), 2) end‐tidal expiratory (ETE), 3) INSP following hyperoxic breathing (HX), and 4) INSP following hyperventilation (HV). HR data from all apneas were analyzed in 10s bins. The first 5 bins (50s) of each apnea were compared between sexes in these analyses. INSP caused similar changes in HR between sexes (‐8 ± 11 and ‐7 ± 6 bpm, P=0.8), and the time courses of the changes in HR were also similar. Although the nadir bradycardic response to ETE (designed to unload lung stretch receptors) was similar between men and women (‐9 ± 7 and ‐9 ± 8 bpm, P=0.9) onset of bradycardia was delayed in women (30s bin) compared with men, in whom the bradycardia was immediate (10s bin). During HX (eliminating the influence of O2) and HV (eliminating the influence of CO2) both the time courses of the HR responses and the HR nadirs (HX: ‐17 ± 13 and ‐14 ± 11 bpm, P=0.6; HV: ‐33 ± 12 and ‐35 ± 17 bpm, P=0.9) were similar between men and women, respectively. These data suggest that sex differences in HR responses to apnea are not dependent on changes in O2 or CO2 but, rather, are unveiled during the unloading of lung stretch receptors. Supported by NSERC, AIHS, Mount Royal University Innovation Grant, and the University of Alberta Human Performance Scholarship Fund.

Sex differences in heart rate responses to sub-maximal exercise in young adults

There is paucity of scientific information on sex differences in heart rate (HR) responses during and after a sub-maximal exercise test in young adults. We assessed sex differences in normal HR responses during and after a sub-maximal-effort cycle ergometer exercise test in apparently healthy young adults. One hundred young adults (50 males and 50 females) participated in the study. Subjects performed a sub-maximal exercise at an intensity that produced 60–85% of a pre-determined age-predicted maximum HR. Measurements of subjects’ HR were done at rest, during exercise and post exercise recovery periods. The present data indicated that after adjusting for covariates, greater (P&lt;0.05) HR responses (delta HR 2 min, delta HR 5 min, delta peak HR) were observed in men relative to women. Males also indicated significantly higher (P&lt;0.05) %HRmax and %HRreserve compared to females. Variables of HR response during post-exercise recovery did not differ between males and females. HR responses during exercise were greater in young adult males compared to females while HR responses at post-exercise recovery were similar between the two groups. The present findings may be useful in interpreting more accurately the significance of HR responses during and after exercise in healthy young adults according to sex.

Heart rate response to a climber’s fall in sport climbing

Chaloupsky, D. (2015). Heart rate response to a climber’s fall in sport climbing J. Hum. Sport Exerc., 9(Proc1), pp.S218-S226. The research deals with response of heart rate to a climber’s simulated fall in a leading position when indoor climbing. Heart rate of climbers was recorded during ascents of an overhanging route in the leading position, to the given point high above the ground, followed by falling into the last protection. The length of the free fall was defined by the place of the last belay anchor, which was at the height of climber’s ankles. The length of the fall was about two meters of free fall plus the consequent rope shift in dynamic belaying system. The total length of the fall was 3 to 6 meters, depending on the dynamic belaying. The sample comprised 14 participants at the age of 16 ‐ 43; 12 men and 2 women; all the participants were advanced climbers experienced with a fall in the position of a lead. Heart rate values observed during the fall did not significantly exceed the heart rate values during the actual climbing, when climbers usually reach 84 - 96% of their maximal heart rate (1 exception). The results of the analysis suggest inter-individual differences in heart rate response to the load when climbing and subsequently falling, particularly during the fall and also in the recovery of the actual fall. Key words: CLIMBING, ROCK CLIMBING, PHYSIOLOGY, FEAR, STRESS.

Relationship Between Exercise Heart Rate and Age in Men vs Women

ObjectiveTo analyze a large cohort of patients who underwent exercise testing and also report sex differences in other exercise heart rate (HR) parameters to determine whether separate sex-based equations to predict peak HR are indicated. Patients and MethodsPatients aged 40 to 89 years who performed treadmill exercise tests (Bruce protocol) from September 21, 1993, to December 20, 2010, were included. Patients with cardiovascular disease or taking HR-attenuating drugs were excluded. After analyses on preliminary cohort, peak HR–modifying factors were eliminated to obtain a pure data set. Analysis of variance was used to test difference in HR responses by sex with age adjustment. ResultsA total of 37,010 patients (67.3% men) were included in the preliminary cohort. Men had higher peak HR (166±17 vs 163±16 beats/min [bpm]; P<.001), HR reserve (90±19 vs 84±17 bpm; P<.001), and HR recovery (19±8 vs 18±9 bpm; P<.03). Poor exercise capacity, current smoking, diabetes, and obesity had significant peak HR–lowering effects (all P<.001). In a pure cohort of 19,013 patients (51.3% of full cohort) without these factors, regression lines approximated more closely the traditional line of 220 – age. For men, the regression line in our final cohort was peak HR = 220 – 0.95 × age. For women, both slope (0.79 bpm/y) and intercept (210 bpm) were still substantially different from those obtained with the traditional formula. ConclusionThe HR responses to exercise are different in men and women. The HR response of men was close to that obtained with the traditional formula, but peak HR in women had a lower intercept and decreased more slowly with age. A separate formula for peak HR in women appears to be appropriate.

Influence of Game Format and Number of Players on Heart Rate Responses and Physical Demands in Small-Sided Soccer Games

The aim of the study was to examine the extent to which changing the game format (possession play vs. regulation goals and goalkeepers vs. small goals only) and the number of players (3 vs. 3, 5 vs. 5 and 7 vs. 7) influenced the physiological and physical demands of small-sided games (SSGs) in soccer in semiprofessional players. Fourteen semiprofessional male soccer players were monitored with global positioning system and heart rate devices. Heart rate, player load, distance covered, running speed, and the number of accelerations were recorded for 9 different SSGs. The results show that changes both in game format and the number of players affect the players' physiological and physical demands. Possession play places greater physiological and physical demands on players, although reducing the number of players only increases the physiological load. In the 7 vs. 7 games, changing the game format did not alter the heart rate responses. Finally, in the possession play format, changing the number of players did not produce significant differences in heart rate responses, although physical demands did decrease in line with a reduction in the number of players. These results should help coaches to understand how modifying different aspects of SSGs has a differential effect on the players' physiological and physical demands. Moreover, coaches in semiprofessional and amateur teams have now consistent information to design and optimize their training time in mixing the technical, tactical, and physical aspects.

Decomposing developmental differences in probabilistic feedback learning: A combined performance and heart-rate analysis

Learning on the basis of outcome feedback shows pronounced developmental changes, however, much is still unknown about its underlying processes. In the current study, we aimed at decomposing how value updating, feedback monitoring and executing behavioral control contribute to children's probabilistic feedback learning. Children (ages 8–9), young adolescents (ages 11–13) and young adults (ages 18–24), performed two probabilistic feedback tasks: one required building a value representation on the basis of feedback (noninformed task), while in the other value representations were explicitly presented (informed task). Heart-rate was recorded to augment performance measures of feedback processing. We observed substantial developmental differences in heart-rate responses toward feedback in the noninformed task. Adult's heart-rate slowed more to negative compared to positive feedback relative to the children and young adolescents. In contrast, in the informed task all age groups showed larger heart-rate slowing toward negative compared to positive feedback. These results indicate that children are not impaired in monitoring probabilistic feedback per se, but have a specific deficit in building a task-appropriate value representation on the basis of probabilistic feedback.

Reclassification of Cardiovascular Risk in Patients With Normal Myocardial Perfusion Imaging Using Heart Rate Response to Vasodilator Stress

Previous studies have shown that patients with normal vasodilator myocardial perfusion imaging (MPI) findings remain at a greater risk of future cardiac events than patients with normal exercise MPI findings. The aim was to assess improvement in risk classification provided by the heart rate response (HRR) in patients with normal vasodilator MPI findings when added to traditional risk stratification. We retrospectively studied 2,000 patients with normal regadenoson or adenosine MPI findings. Risk stratification was performed using Adult Treatment Panel III framework. Patients were stratified by HRR (percentage of increase from baseline) into tertiles specific to each vasodilator. All-cause mortality and cardiac death/nonfatal myocardial infarction (MI) ≤2 years from the index MPI were recorded. During follow-up, 11.8% patients died and 2.7% patients experienced cardiac death/nonfatal MI in the adenosine and regadenoson groups, respectively. The patients who died had a greater Framingham risk score (12 ± 4 vs 11 ± 4, p= 0.009) and lower HRR (22± 16 vs 32 ± 21, p <0.0001). In an adjusted Cox model, the lowest tertile HRR was associated with an increased risk of mortality (hazard ratio 2.1) and cardiac death/nonfatal MI (hazard ratio 2.9; p <0.01). Patients in the highest HRR tertile, irrespective of the Adult Treatment Panel III category, were at low risk. When added to the Adult Treatment Panel III categories, the HRR resulted in net reclassification improvement in mortality of 18% and cardiac death/nonfatal MI of 22%. In conclusion, a blunted HRR to vasodilator stress was independently associated with an increased risk of cardiac events and overall mortality in patients with normal vasodilator MPI findings. The HRR correctly reclassified a substantial proportion of these patients in addition to the traditional risk classification models and identified patients with normal vasodilator MPI findings, who had a truly low risk of events.

Heart rate monitoring in soccer: interest and limits during competitive match play and training, practical application.

The identification of physiological loads imposed by soccer training or match play reveals essential information, which may help improve training and recovery strategies. Until today, the use of heart rate (HR) monitoring is not standardized in soccer. Thus, the aim of this review was to analyze, determine and compare the exercise intensity (EI) monitored by HR in professional, youth, and recreational soccer players during matches and training sessions using a meta-analysis. Heart rate is one of the most common physiological variables used to determine exercise internal training load. The mean EI recorded during competitive matches was described as 70-80% of VO2max or 80-90% of maximal heart rate (HRmax), independent of the playing level. With respect to HR training zones, approximately 65% of the total match duration is spent at intensity of 70-90% HRmax and rarely below 65% HRmax. However, although HRmax is mostly employed in the literature, monitoring EI should be expressed in relation to reserve heart rate, as it was described as a more reliable indicator of HR, allowing interindividual comparisons. The HR response according to the playing position indicates that midfielders are characterized by the highest EI, followed by forwards and fullbacks. Moreover, in the second half of the match, the EI is lower than that observed during the first half; this reduction could be correlated with the level of the player's physical conditioning. Consequently, coaches may favor the use of interval training or small-sided training games because these are shown to improve both aerobic capacity and the ability to repeat high-intensity actions. Small-sided games allow reaching similar HR responses to those found during interval training and match play but with greater heterogeneity values. Future investigations should include a larger sample of players with special reference to playing position and the expression of EI in percentage of the reserve heart rate, analyzing the possible intergender differences in HR response.

The impact of a naturalistic hands-free cellular phone task on heart rate and simulated driving performance in two age groups

Heart rate and driving performance were assessed while late middle age (51–66) and younger adults (19–23) engaged in a naturalistic hands free phone task that was designed to place objectively equivalent cognitive demands on all participants. Although heart rate measures have been used in evaluating driver workload, prior studies had not compared responses in late middle age and younger adults with samples of sufficient size to begin to explore possible age relationships. In an evaluation of 37 participants, the two age groups displayed equivalent performance on the cellular telephone task and concurrent decrements in speed control (SD velocity). It was observed that the late middle age subjects drove more slowly overall and, as a group, did not demonstrate heart rate acceleration in response to the phone conversation that was seen in younger drivers. The possibility that age group differences in heart rate response are related to individual differences in attentional focus is raised. While there are significant reasons to discourage all individuals from engaging in phone conversations and other distracting tasks while driving, late middle age adults appeared as capable as young adults of managing the additional workload of a low to moderately demanding cognitive task of the type assessed. The tendency of individuals to adopt self-regulatory behaviors, such as a lower overall driving speed, as a function of age/experience may account for the equivalence in overt performance.

Heart rate responses to standardized trauma-related pictures in acute posttraumatic stress disorder

Physiological responses to trauma reminders are one of the core symptoms of posttraumatic stress disorder (PTSD). Nevertheless, screening measures for PTSD largely rely on symptom self-reports. It has been suggested that psychophysiological assessments may be useful in identifying trauma survivors with PTSD (Orr and Roth, 2000). This study investigated whether heart rate (HR) responses to standardized trauma-related pictures distinguish between trauma survivors with and without acute PTSD.Survivors of motor vehicle accidents or physical assaults (N=162) watched standardized trauma-related, generally threatening and neutral pictures at 1month post-trauma while their ECG was recorded. At 1 and 6months, structured clinical interviews assessed PTSD diagnoses. Participants completed self-report measures of PTSD severity and depression, peritraumatic responses, coping behaviors and appraisals.Trauma survivors with acute PTSD showed greater HR responses to trauma-related pictures than those without PTSD, as indicated by a less pronounced mean deceleration, greater peak responses, and a greater proportion showing HR acceleration of greater than 1 beat per minute. There were no group differences in HR responses to generally threatening or neutral pictures. HR responses to trauma-related pictures contributed to the prediction of PTSD diagnosis over and above what could be predicted from self-reports of PTSD and depression. HR responses to trauma-related pictures were related to fear and data-driven processing during the trauma, safety behaviors, suppression of trauma memories, and overgeneralized appraisals of danger.The results suggest that HR responses to standardized trauma-related pictures may help identify a subgroup of patients with acute PTSD who show generalized fear responses to trauma reminders. The early generalization of triggers of reexperiencing symptoms observed in this study is consistent with associative learning and cognitive models of PTSD.

Developmental Changes in Hemodynamic Responses and Cardiovagal Modulation during Isometric Handgrip Exercise

The purpose of this study was to examine differences in pressor response and cardiovagal modulation during isometric handgrip exercise (IHG) between children and adults. Beat-to-beat heart rate (HR) and blood pressure were measured in 23 prepubertal children and 23 adults at baseline and during IHG. Cardiovagal modulation was quantified by analysis of HR variability. Mean arterial pressure responses to IHG were greater in adults compared to children (P < .05) whereas there were no group differences in HR responses (P > .05). Children had a greater reduction in cardiovagal modulation in response to IHG compared to adults (P < .05). Changes in mean arterial pressure during IHG were correlated with baseline cardiovagal modulation and force produced during isometric contraction (P < .05). In conclusion, differences in pressor reflex response between children and adults cannot be solely explained by differences in autonomic modulation and appear to be associated with factors contributing to the force produced during isometric contraction.

Differences in heart rate response to adenosine and regadenoson in patients with and without diabetes mellitus

Adenosine and regadenoson increase heart rate (HR) when used as stress agents to produce coronary hyperemia due to direct sympathetic stimulation. We hypothesized that the HR response will be lower in patients with than in those without diabetes mellitus (DM). We studied the HR response (percentage maximal increase) in 2,000 patients in The ADenoscan Versus regAdenosoN Comparative Evaluation for Myocardial Perfusion Imaging (ADVANCE MPI 1 and 2) Trials with known DM status. There were 643 patients with a history of DM (65.4 +/- 0.4 years, 32% women) and 1,357 patients with no DM (65.5 +/- 0.3 years, 29% women). Compared with non-DM, the DM group had higher HR at baseline (68.4 +/- 0.48 vs 65.2 +/- 0.31 beat/min, P < .001) and smaller HR response after adenosine or regadenoson administration (29.4% +/- 0.64% vs 36.1% +/- 0.54%, P < .001). Insulin therapy was associated with further blunting in the HR response (25.9% +/- 1.0% vs 31.2% +/- 0.8%, P < .001). After adjusting for beta-blocker intake, baseline HR, age, gender, renal function, systolic blood pressure, and left ventricular systolic function, DM independently accounted for a decrease in the HR response. The HR response to adenosine and regadenoson in patients with DM is blunted. If additional studies confer an agreement between traditional tests for determination of autonomic neuropathy and this measure, then examination of HR response to these agents during myocardial perfusion imaging might add prognostic power.

Safety Behaviors and Social Performance in Patients With Generalized Social Phobia

The cognitive model of social phobia (Clark &amp; Wells, 1995) suggests that safety behaviors, besides preventing disconfirmation of dysfunctional beliefs, cause significant impairment in social performance. To test this hypothesis, the current study investigated the relationship between observer-rated social performance, self-rated safety behaviors, and anxiety in 20 generalized social phobics, 14 controls with anxiety, and 17 controls without anxiety in two experimental tasks: a conversation with a stooge and a brief speech. Compared to the control groups, socially phobic patients displayed higher anxiety levels, reported more safety behaviors, and did not perform as well as the control groups in both tasks. There was a nonsignificant tendency of socially phobic patients to display more negative thoughts than both control groups. Differences in heart rate responses were not significant. A path analysis revealed that safety behaviors partially mediated the relation between diagnostic group and social performance deficit in both tasks. The results highlight the importance of safety behaviors for social performance deficit in social phobia.

α7-Nicotinic acetylcholine receptor subunit is not required for parasympathetic control of the heart in the mouse

Nicotinic acetylcholine receptors (nAChR) are assembled from a pool of nine alpha-subunits and three beta-subunits into functional pentamers in peripheral autonomic neurons. The contribution of different subunits to native, physiologically important nAChR for synaptic transmission in autonomic ganglia is unclear. Here, we examined the importance of the alpha7-subunit for parasympathetic innervation of the heart. Normal (C57BL/6J), alpha7-deficient (Chrna7), and wild-type littermate mice were implanted with telemetry devices, and, under conscious, unsedated conditions, ECG recordings were obtained at baseline and after atropine, propranolol, and hexamethonium bromide administration. Spectral analysis of heart rate variability [power spectral analysis (PSA)] was performed for the evaluation of resting autonomic tone to the heart. At the completion of conscious studies, animals were anesthetized and underwent electrical stimulation of the vagus nerve (VS) while R-R intervals were recorded. Heart rate at baseline and after atropine, propranolol, or hexamethonium was similar in all three groups of animals. PSA curves were similar between normal, wild-type, and Chrna7 mice. VS showed no difference between control and Chrna7 mice throughout the range of stimulation (5-20 Hz). Mice deficient in the alpha7-nAChR subunit do not display differences in resting autonomic tone to the heart at baseline or under conditions of single and combined autonomic blockade. VS showed no difference in heart rate responses between normal and alpha7-deficient mice. These data support previous findings in vitro and highlight the important differences in function between nicotinic receptor subtypes because alpha3-deficient mice display major autonomic dysfunction. We conclude that the alpha7-subunit does not contribute critically to resting parasympathetic control of the heart.

Blood flow response to a postural challenge in older men and women

BackgroundThe purpose of this study was to measure blood flow in the carotid and femoral arteries, heart rate and blood pressure in response to postural challenge in older adults. A second purpose was to determine if older men and women have different cardiovascular responses to a postural challenge such as tilt.MethodsThirty-seven healthy elderly men and women participated in this study (69–82 years old). All subjects had similar physical activity levels. Postural challenge was induced by a 60° tilt at the level of the waist. Continuous carotid blood flow and femoral blood flow was measured with Doppler ultrasound.ResultsCarotid blood flow was significantly reduced 17% in both men and women immediately after tilt (p < 0.001), and by 3.2% two minutes after tilt (p < 0.001). Femoral blood flow decreased 59.4% in men and 61% in women immediately after tilt (p < 0.001), and remained significantly decreased two minutes after tilt by 21% (p <0.001). Heart rate increased by 15% in men (p < 0.001), and 26% in women immediately after the tilt (p < 0.001). Heart rate returned to resting values within two minutes in both men and women. Response to tilt was not significantly related to self-report physical activity levels or to six-minute walk time.ConclusionA postural challenge induced larger changes in the femoral artery compared to the carotid artery. There were no differences between men and women to a tilt table test except for differences in heart rate response. There was no difference in the blood flow responses to postural challenge with physical activity level or between healthy older men and women.

Blunted cortisol responses to psychosocial stress in asthmatic children: a general feature of atopic disease?

Atopy is defined by the individual predisposition to develop a group of inflammatory disorders in response to certain food or environmental substances that are otherwise innocuous for the host. In previous studies we could demonstrate a reduced responsiveness of the hypothalamus-pituitary-adrenal (HPA) axis to psychosocial stress in young and adult patients with atopic dermatitis (AD), a chronic atopic skin disorder. With respect to the important immunoregulatory role of the HPA axis, especially under stress, this observation could be of clinical relevance and may at least partly explain stress-induced exacerbation of AD. The present study was designed to investigate whether attenuated responsiveness of the HPA axis to stress represents a characteristic feature of AD or whether it can also be found in other chronic manifestations of atopy. Children (aged 7-12) with allergic asthma (AA; N = 17) and age- and sex-matched healthy controls (N = 18) were exposed to the "Trier Social Stress Test for Children"(TSST-C), which mainly consists of a free speech and mental arithmetic tasks in front of an audience. Salivary cortisol was measured in ten-minute intervals before and after the TSST-C, while heart rate was monitored continuously. In addition, early morning cortisol levels (after awakening, +10, +20, +30 minutes) were assessed on three consecutive days. Data analysis yielded a significant increase of cortisol concentrations (F (9297)= 16.79; p <.001) and heart rates (F(32,992)= 9.16; p <.001) after the stressor with no between-group difference in heart rate responses. However, AA children showed a significantly blunted cortisol response to the TSST-C when compared with the control group (F(9297)= 2.95; p <.01). Awakening in the morning was accompanied by a significant rise of cortisol levels on all three experimental days in AA and control subjects (all p <.001) that was not different between the two groups. These findings suggest that a blunted adrenocortical response to stress may represent a common feature of chronic allergic inflammatory processes that may be relevant in different forms of chronic manifestation of atopy.

Arousal Styles during Public Speaking

The nature of the public-speaking context as a physiologically arousing communication context is well-known. During public speaking, a significant increase in heart rate level above the baseline has been found in various studies. In these studies, arousal styles during speaking have generally been described on the basis of mean heart rates among a group of participants. Individual variation in HR responses has not received much attention. The purpose of the present study was to examine individual differences in heart rate responses during public speaking and to account for these differences in terms of particular explanatory variables. The heart rate curves of 47 speakers were examined one by one in order to see what different arousal styles emerged. As a result, four styles were distinguished: the confrontation style, inflexible style, insensitive style, and average style. Different combinations of the speaker's subjectively experienced state, level of trait anxiety, and public speaking experience were typically associated with each of these styles.