Impact of moderate-intensity aerobic exercise in combined hypoxic and hot conditions on endothelial function.

There is no study that has investigated the impact of exercise in a combined hypoxic and hot environment on endothelial function. Therefore, we tested whether aerobic exercise in a combined hypoxic and hot conditions induces further enhancement of endothelial function. Twelve healthy males cycled at a constant workload (50% of their maximal oxygen uptake under normoxic/thermoneutral conditions) for 30 min in four different environments: exercise under normoxic condition (NOR: fraction of inspiratory oxygen or FiO2 = 20.9%, 20°C), exercise under hypoxic condition (HYP: FiO2 = 14.5%, 20°C), exercise under hot condition (HOT: FiO2 = 20.9%, 30°C), and exercise under combined hypoxia and hot conditions (HH: FiO2 = 14.5%, 30°C). Before, during, and after exercise, cardiovascular variables (e.g., heart rate, blood flow, and shear rate), blood variables, and endothelial function evaluated by flow-mediated dilation (FMD) were assessed. Heart rates were significantly higher throughout the HH trial's experimental period than the other trials (p < 0.05). However, in the HH trial, brachial artery blood flow and shear rate did not differ from those in other trials after exercise. Plasma catecholamines (epinephrine, norepinephrine, and dopamine) elevations in response to exercise were significantly higher in the HH trial than in the other three trials (p < 0.05). No considerable differences were observed in FMD responses among trials before and after the exercise. In conclusion, aerobic exercise in a combined hot and hypoxic environment further activated sympathetic nervous activity but did not considerably enhance blood flow, shear rate, or endothelial function.

A descending pathway from the lateral/ventrolateral PAG to the rostroventral medulla mediating the vasomotor response evoked by social defeat stress in rats.

The stress-induced cardiovascular response is based on the defensive reaction in mammals. It has been shown that the sympathetic vasomotor pathway of acute psychological stress is indirectly mediated via neurons in the rostroventral medulla (RVM) from the hypothalamic stress center. In this study, direct projections to the RVM and distribution of neuroexcitatory marker c-Fos-expressed neurons were investigated during social defeat stress (SDS) in conscious rats. The experimental rat that was injected with a neural tracer, FluoroGold (FG) into the unilateral RVM, was exposed to the SDS. Double-positive neurons of both c-Fos and FG were locally distributed in the lateral/ventrolateral periaqueductal gray matter (l/vl PAG) in the midbrain. These results suggest that the neurons in the l/vl PAG contribute to the defensive reaction evoked by acute psychological stress, such as the SDS. During the SDS period, arterial pressure (AP) and heart rate (HR) showed sustained increases in the rat. Therefore, we performed chemical stimulation by excitatory amino acid microinjection within the l/vl PAG and measured cardiovascular response and sympathetic nerve activity in some anesthetized rats. The chemical stimulation of neurons in the l/vl PAG caused significant increases in arterial pressure and renal sympathetic nerve activity. Taken together, our results suggest that neurons in the l/vl PAG are a possible candidate for the cardiovascular descending pathway that modulates sympathetic vascular resistance evoked by acute psychological stress, like the SDS.NEW & NOTEWORTHY The sympathetic vasomotor pathway of an acute psychological stress-induced cardiovascular response is mediated via neurons in the RVM indirectly from the hypothalamus. In this study, we showed the relaying area of the efferent sympathetic vasomotor pathway from the hypothalamus to the RVM. The results suggested that the pressor response during psychological stress is mediated via neurons in the lateral/ventrolateral PAG to the RVM.

The interaction of breath holding and muscle mechanoreflex on cardiovascular responses in breath-hold divers and non-breath-hold divers.

Cardiovascular responses to diving are characterized by two opposing responses: tachycardia resulting from exercise and bradycardia resulting from the apnea. The convergence of bradycardia and tachycardia may determine the cardiovascular responses to diving. The purpose of this study was to investigate the interaction of breath holding and muscle mechanoreflex on cardiovascular responses in breath-hold divers (BHDs) and non-BHDs. We compared the cardiovascular responses to combined apnea and the mechanoreflex in BHDs and non-BHDs. All participants undertook three trials-apnea, passive leg cycling (PLC), and combined trials-for 30 s after rest. Cardiovascular variables were measured continuously. Nine BHD (male:female, 4:5; [means ± SD] age, 35 ± 6 years; height, 168.6 ± 4.6 cm; body mass, 58.4 ± 5.9 kg) and eight non-BHD (male:female, 4:4; [means ± SD] age, 35 ± 7 years; height, 163.9 ± 9.1 cm; body mass, 55.6 ± 7.2 kg) participants were included. Compared to the resting baseline, heart rate (HR) and cardiac output (CO) significantly decreased during the combined trial in the BHD group, while they significantly increased during the combined trials in the non-BHD group (P < 0.05). Changes in the HR and CO were significantly lower in the BHD group than in the non-BHD group in the combined trial (P < 0.05). These results suggest that bradycardia with apnea in BHDs is prioritized over tachycardia with the mechanoreflex, whereas that in non-BHDs is not. This finding implies that diving training changes the interaction between apnea and the mechanoreflex in cardiovascular control.

Passive heating-induced changes in muscle contractile function are not further augmented by prolonged exposure in young males experiencing moderate thermal stress.

Background: We investigated the impact of 1) passive heating (PH) induced by single and intermittent/prolonged hot-water immersion (HWI) and 2) the duration of PH, on muscle contractile function under the unfatigued state, and during the development of muscle fatigue. Methods: Twelve young males volunteered for this study consisting of two phases: single phase (SP) followed by intermittent/prolonged phase (IPP), with both phases including two conditions (i.e., four trials in total) performed randomly: control passive sitting (CON) and HWI (44-45°C; water up to the waist level). SP-HWI included one continuous 45-min bath (from 15 to 60 min). IPP-HWI included an initial 45-min bath (from 15 to 60 min) followed by eight additional 15-min baths interspaced with 15-min breaks at room temperature between 75 and 300 min. Intramuscular (Tmu; measured in the vastus lateralis muscle) and rectal (Trec) temperatures were determined. Neuromuscular testing (performed in the knee extensors and flexors) was performed at baseline and 60 min later during SP, and at baseline, 60, 90, 150 and 300 min after baseline during IPP. A fatiguing protocol (100 electrical stimulations of the knee extensors) was performed after the last neuromuscular testing of each trial. Results: HWI increased Tmu and Trec to 38°C-38.5°C (p < 0.05) during both SP and IPP. Under the unfatigued state, HWI did not affect electrically induced torques at 20 Hz (P20) and 100 Hz (P100). However, it induced a shift towards a faster contractile profile during both SP and IPP, as evidenced by a decreased P20/P100 ratio (p < 0.05) and an improved muscle relaxation (i.e., reduced half-relaxation time and increased rate of torque relaxation; p < 0.05). Despite a reduced voluntary activation (i.e., -2.63% ± 4.19% after SP-HWI and -5.73% ± 4.31% after IPP-HWI; condition effect: p < 0.001), HWI did not impair maximal isokinetic and isometric contraction torques. During the fatiguing protocol, fatigue index and the changes in muscle contractile properties were larger after HWI than CON conditions (p < 0.05). Finally, none of these parameters were significantly affected by the heating duration. Conclusion: PH induces changes in muscle contractile function which are not augmented by prolonged exposure when thermal stress is moderate.

The power of personal control: Task choice attenuates the effect of implicit sadness on sympathetically mediated cardiac response.

Implicitly processed pictures of facial expressions of emotions have been found to systematically influence sympathetically mediated cardiovascular reactivity during task performance. According to the Implicit-Affect-Primes-Effort model, this happens because different affect primes activate the concepts of performance ease versus performance difficulty. Grounded in a recent action shielding model, our laboratory experiment (N = 129 university students) tested whether engaging in action by personal choice can immunize against those implicit affective influences on effort. Participants worked on an objectively difficult cognitive task, which was either externally assigned or ostensibly personally chosen. As predicted, participants in the assigned task condition showed weaker cardiac pre-ejection period reactivity during task performance, reflecting disengagement, when they were primed with sadness than when they were exposed to anger primes. Most relevant, this affect prime effect disappeared when participants could ostensibly choose their task themselves. These findings replicate previous research on implicit affect's impact on sympathetically mediated cardiac response and extend the literature on action shielding by personal choice effects to implicit affective influences on action execution.

Personal task choice attenuates implicit happiness effects on effort: A study on cardiovascular response.

Research on the Implicit-Affect-Primes-Effort model (Gendolla, 2012) found that priming happiness or anger in challenging tasks results in stronger sympathetically mediated cardiovascular responses, reflecting effort, than priming sadness or fear. Recent studies on action shielding revealed that personal task choice can attenuate affective influences on action execution (e.g., Gendolla et al., 2021). The present experiment tested if this action shielding effect also applies to affect primes' influences on cardiovascular response. Participants (N = 136) worked on a cognitive task with integrated briefly flashed and backward masked facial expressions of sadness vs. happiness. Half of the participants could ostensibly choose whether they wanted to work on an attention or on a memory task, while the other half was assigned to one task. Our findings revealed effects on cardiac pre-ejection period (PEP), which align with the expected outcomes for a task of unfixed difficulty where participants establish their own performance standard. Most importantly, task choice shielded against the implicit affective influence on PEP that was evident when the task was externally assigned. Effects on systolic blood pressure (SBP) reactivity largely corresponded to those of PEP.

Noise annoys-But personal choice can attenuate noise effects on cardiac response reflecting effort.

Since personal choice fosters commitment and shields action execution against potentially conflicting influences, two laboratory experiments with university students (N = 228) tested whether engaging in action by personal choice versus external assignment of task characteristics moderates the effect of irrelevant acoustic noise on cardiovascular responses reflecting effort. Participants who could personally choose the stimulus color of moderately difficult cognitive tasks were expected to be shielded against the irrelevant noise. By contrast, when the stimulus color was externally assigned, we predicted receptivity for the irrelevant noise to be high. As expected, in both experiments, participants in the assigned color condition showed stronger cardiac pre-ejection period reactivity during task performance when exposed to noise than when working in silence. On the contrary, participants who could choose the stimulus color were shielded against the noise effect on effort. These findings conceptually replicate and extend research on the action shielding effect by personal choice and hold practical implications for occupational health.

Challenge or Threat? The Effects of the Standard and a Second-Generation Mindfulness Intervention with Buddhist Practices on Cognitive Appraisals of Stress: Secondary Analysis of a Randomized Controlled Experiment Performed in Switzerland.

Contemplative approaches rooted in Buddhist traditions have been linked to the attenuation of response to social stress. Anticipatory cognitive appraisals of social situations potentially represent a mechanism explaining the stress-reducing effects of contemplative practices. The cognitive appraisal of threat is associated with an anticipated loss of social self-esteem. In contrast, the cognitive appraisal of challenge involves recognizing the potential for gain or growth in stressful situations and is associated with a more adaptive cardiovascular response. In this secondary analysis of a randomized controlled experiment performed in Switzerland, we evaluated the effects of two contemplative interventions on cognitive appraisals of challenge and threat and associated physiological profiles. The interventions were a standard Mindfulness-Based Stress Reduction (MBSR) program and a new program (MBSR-B), which included several elements from Buddhist practices. After an eight-week intervention, participants completed the Trier Social Stress Test (TSST) and underwent the assessment of primary cognitive appraisals and cardiovascular response to stress. The results demonstrated greater challenge appraisal in the MBSR (n = 20) and MBSR-B (n = 21) groups compared to Control (n = 24), and MBSR-B participants scored higher on the challenge than threat appraisal. At the physiological level, the groups did not differ on changes in cardiac output and total peripheral resistance. Still, an exploratory analysis demonstrated that the MBSR-B group's cardiovascular profile best resembled challenge appraisal. The results suggest that contemplative approaches foster challenge appraisal, contributing to a more adaptive response to stress.

Effect of pre-use of Dexmedetomidine on the effective inhibitory dose of remimazolam tosilate on positive cardiovascular response in double-lumen endobronchial intubation: a clinical study.

BACKGROUND: Herein, the effect of pre-use of Dexmedetomidine(Dex) on the half-effective dose (ED50) and 95%-effective dose (ED95) of Remimazolam tosilate(RT) in inhibiting the positive cardiovascular response(CR) which means blood pressure or heart rate rises above a critical threshold induced by double-lumen bronchial intubation was evaluated. METHODS: Patients who underwent video-assisted thoracic surgery were divided into groups A (0), B (0.5 µg/kg), and C (1 µg/kg) based on different Dex doses. Group A included subgroups comprising young (A-Y) and elderly (A-O) patients. Neither groups B nor C included elderly patients due of the sedative effect of Dex. Based on the previous subject's CR, the dose of RT was increased or decreased in the next patient using the sequential method. This trial would be terminated when the seventh crossover occurred, at which point the sample size met the stable estimate of the target dose. Heart rate (HR) and mean arterial pressure (MAP) were monitored throughout the trial, and sedation was assessed using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. HR and MAP were recorded at baseline (T1), the end of Dex (T2), and the end of RT (T3), the maximum HR and MAP were recorded within 3 min of intubation from beginning to end (T4). There was a positive CR when the T4 levels rose above 15% of the baseline. The ED50/ED95 and corresponding confidence interval were calculated using probability regression. RESULTS: In total, 114 patients completed the trial. Without the use of Dex, the ED50/ED95 of TR inhibiting the positive CR caused by double-lumen bronchial intubation was 0.198/0.227 and 0.155/0.181 mg/kg in groups A-Y and A-O, respectively. The changes in vital signs from T1 to T3 were similar in the subgroups, indicating that the elderly patients were more sensitive to the dose of RT. The ED50/ED95 of RT inhibiting the positive CR caused by double-lumen endobronchial intubation was 0.122/0.150 and 0.068/0.084 mg/kg in groups B and C, respectively. And, the fluctuation of blood pressure from T3 to T4 was reduced by using Dex. RT was 100% effective in sedation with no significant inhibition of circulation. Apart from one case of hypotension occurred in group A-Y, two cases of low HR in group B, and one case of low HR in group C, no other adverse events were noted. CONCLUSIONS: The optimal dose of RT to inhibit positive CR induced by double-lumen bronchial intubation in elderly patients was 0.18 mg/kg and 0.23 mg/kg in younger patients. When the pre-use dose of Dex was 0.5 µg/kg, the optimal dose to inhibit positive CR of RT was 0.15 mg/kg. And, when the pre-use dose of Dex was 1 µg/kg, the optimal dose of RT was 0.9 mg/kg. CLINICAL TRIAL REGISTRATION: NCT05631028.

The effect of social comparison on effort: When similar and slightly better peers increase effort-related cardiovascular responses.

Social comparison theory states that comparison with others should influence an individual's behavior (Festinger, 1954; Munkes & Diehl, 2003). This is primarily due to an upward pressure: the pressure to be better than others, which according to some theories should motivate individuals to increase their level of performance (Munkes & Diehl, 2003; Rijsman, 1974). The effect of upward pressure on individual performance has been tested, but never on effort. To address this gap, we conducted a within-subject design study with N = 40 participants engaged in five-minute video games while presented with scores of a similar, slightly better, or weaker peer, with a control condition omitting the peer's score. Effort-related cardiovascular responses were recorded with initial systolic time interval (ISTI) during the game and baseline conditions. The effect of social comparison on effort was tested with a 4 (social comparison) x 5 (minutes of the tasks) repeated-measures ANOVA on ISTI reactivity. Results showed higher ISTI reactivity, interpreted as increased effort, when participants competed with similar and slightly better peers compared to a weaker peer and the control condition in the last minute of the task, confirming our expectations (Pegna et al., 2019). These results illustrate that social comparison - through its effect on upward pressure - is sufficient to elicit changes in effort-related cardiovascular response.

Role of cytochrome P450-epoxygenase and soluble epoxide hydrolase in the regulation of vascular response.

The role of cytochrome P450-epoxygenase has been seen in cardiovascular physiology and pathophysiology. The aberration in CYP450-epoxygenase genes occur due to genetic polymorphisms, aging, or environmental factors, that increase susceptibility to cardiovascular diseases (CVDs). The actual role played by the CYP450-epoxygenases is the metabolism of arachidonic acid (AA) and linoleic acid (LA) into epoxyeicosatrienoic acids (EETs) and epoxyoctadecaenoic acid (EpOMEs) metabolites (oxylipins) and others, which is involved in vasodilation and myocardial-protection. But the genetic polymorphisms in CYP450-epoxygenases lose their beneficial cardiovascular effects of oxylipins, and the soluble epoxide hydrolase (sEH) antagonizes beneficial oxylipins into diols. Like sEH converts EETs into dihydroxyeicosatrienoic acid (DHETs), EpOMEs into dihydroxyoctadecaenoic acid (DiHOMEs), and reverses its beneficial effects, and the sEH gene (Ephx2) polymorphisms cause the enzyme to become overactive and convert epoxy-fatty acids into diols, making them vulnerable to CVDs, including hypertension. Other, enzymes like ω-hydroxylases (CYP450-4A11 & CYP450-4F2)-derived oxylipins from AA, ω-terminal-hydroxyeicosatetraenoic acids (19-, 20-HETE), lipoxygenase-derived oxylipins, mid-chain hydroxyeicosatetraenoic acids (5-, 11-, 12-, 15-HETEs), and the cyclooxygenase-derived prostanoids (prostaglandins: PGD2, PGF2α; thromboxane: Txs, oxylipins) are involved in vasoconstriction, hypertension, inflammation, and cardiac toxicity. Also, there are significant interactions were seen between adenosine receptors [adenosine A2A receptor (A2AAR) and adenosine A1 receptor (A1AR)] with CYP450-epoxygenases, ω-hydroxylases, sEH, and their derived oxylipins in the regulation of the cardiovascular response. Moreover, polymorphisms exist in CYP450-epoxygenases, ω-hydroxylases, sEH, and the adenosine receptor genes in populations associated with CVDs. This chapter will discuss the role of oxylipins' interactions with adenosine receptors in cardiovascular function/dysfunction in mice and humans.

Effect of Remote Ischemic Conditioning on Heart Rate Responses to Walking in People with Multiple Sclerosis.

Background: Remote ischemic conditioning (RIC), exposure of body parts to brief periods of circulatory occlusion and reperfusion, has been shown to improve cardiovascular responses to exercise in healthy individuals but its effects in people with MS are unknown. Objective: This study aimed to assess the effect of RIC on heart rate responses to walking in people with MS. Design: Double blind randomized controlled trial. Setting: Multiple sclerosis clinic of tertiary care center teaching hospital in the United Kingdom. Methods: Three cycles of RIC were delivered by occluding the upper arm with a blood pressure cuff inflated to a pressure of 30 mmHg above the systolic blood pressure. In the sham group, the blood pressure cuff was inflated to 30 mmHg below diastolic blood pressure. Heart rate responses to the 6-minute walk test (6MWT), the tolerability of RIC using a numerical rating scale for discomfort (0-10), and adverse events were studied. Results: Seventy-five participants (RIC -38 and Sham-37) completed the study. RIC was well tolerated. Compared to sham, RIC significantly decreased the rise in heart rate (P = 0.04) and percentage of predicted maximum heart rate (P = 0.016) after the 6MWT. Conclusion: RIC was well tolerated and improved the heart rate response to walking in people with MS. Further studies on RIC in the management of MS are needed.

Immediate Effects of Aerobic Exercise and Whole-Body Vibration on Fat Oxidation, Lipid Mobilization, and Cardiovascular Response in Individuals with Obesity.

Among obesity, cumulative fat and poor physical activity are risk factors for cardiovascular disease. Due to the limit in performing aerobic exercise (AER), whole-body vibration (WBV) as a passive form of exercise is an alternative therapeutic strategy. Herein, this study aimed to compare the immediate effects of AER and WBV on metabolic and cardiovascular responses, and dyspnea level in obesity. Forty-nine eligible obesities performed both AER and WBV, with a random order assignment (age = 28.94 ± 11.39 years). Fat oxidation, cardiovascular parameters (i.e., heart rate (HR) and blood pressure (BP)), and dyspnea level (i.e., rating perceived exertion (RPE)) were measured during exercise, while lipid mobilization (i.e., triglycerides) was collected pre- and post-exercise. Fat oxidation rate in AER was significantly higher than in WBV. Significantly increased fat oxidation rates were shown in both groups (within-group analyses) (also shown in females aged 20-45). Triglyceride levels between AER and WBV were similar. A significant decrease in triglyceride levels was only observed in WBV (within-group change). HR and RPE in AER were significantly higher than in WBV (p < 0.05). HR and RPE were significantly increased throughout both AER and WBV, while systolic blood pressure was only significantly elevated in AER (whining-group analyses). WBV may facilitate fat oxidation (particularly in females aged below 45), induce lipid mobilization, and reduce interference on cardiovascular parameters in obesity.

Impaired functional exercise capacity and greater cardiovascular response to the 6-min walk test in congenital generalized lipodystrophy.

BACKGROUND: Congenital Generalized Lipodystrophy (CGL) is an ultra-rare disease characterized by metabolic disorders. However, the evaluation of functional exercise capacity, cardiovascular (CV) response to exercise, and peripheral arterial disease (PAD) in CGL is scarce. Here we evaluated the performance and CV response to exercise and their association with PAD in CGL compared to healthy individuals. METHODS: Twelve CGL and 12 healthy subjects matched for age and gender were included. Functional exercise capacity, CV response, and PAD were measured using the six-minute walk test (6MWT) and ankle-brachial index (ABI), respectively. RESULTS: At baseline, CGL subjects showed reduced predicted walked distance (6MWD) (p = 0.009) and increased heart rate (HR), systolic (SBP), and diastolic (DBP) pressures compared to healthy subjects (p < 0.05). Most CGL subjects presented normal ABI values (1.0 ≤ ABI ≤ 1.4). Only 25% (n = 3) had ABI ≤ 0.9. CGL subjects did not present changes in ABI and blood pressure 12 months after metreleptin (MLP) replacement, but they walked a greater 6MWD than baseline (p = 0.04). Further, 6MWD and right ABI measurements were positively correlated in CGL subjects (p = 0.03). Right ABI negatively correlated with glucose, triglycerides, and VLDL-c (p < 0.05). CONCLUSIONS: We observed that CGL subjects had lower functional exercise capacity and higher cardiovascular effort for similar performance of 6MWT, suggesting that strategies for decreasing exercise effort in this population should be essential. Furthermore, better physical performance was associated with high ABI in CGL. Additional studies are needed to clarify leptin's role in preserving functional exercise capacity in CGL.

Incidental affective influences on effort-related cardiac response: The critical role of choosing task characteristics.

This experiment tested whether personal choice vs. external assignment of task characteristics moderates the effect of incidental affective stimulation on effort-related cardiovascular response. We expected strong action shielding and low receptivity for incidental affective influences when participants could choose themselves the stimulus color of an easy memory task. By contrast, when the stimulus color was assigned, we expected weak action shielding and high receptivity. As expected, participants in the assigned color condition showed stronger cardiac pre-ejection period reactivity when exposed to sad music than when exposed to happy music during task performance. These music effects did not appear among participants who could personally choose the stimulus color. Our results replicate previous research by showing that personal choice leads to action shielding, whereas individuals remain receptive for affective influences during volition when task characteristics are assigned.

Effects of regular cannabis and nicotine use on acute stress responses: chronic nicotine, but not cannabis use, is associated with blunted adrenocortical and cardiovascular responses to stress.

RATIONALE: Cannabis is one of the most prevalent substances used by tobacco smokers and, in light of the growing list of states and territories legalizing cannabis, it is expected that co-use of cannabis and nicotine will escalate significantly and will lead to continuing challenges with tobacco use. OBJECTIVES: This study was conducted to examine the interactive effects of chronic cannabis and nicotine use on adrenocortical, cardiovascular, and psychological responses to stress and to explore sex differences in these effects. METHODS: Participants (N = 231) included cannabis-only users, nicotine-only users, co-users of both substances, and a non/light-user comparison group. After attending a medical screening session, participants completed a laboratory stress session during which they completed measures of subjective states, cardiovascular responses, and salivary cortisol during baseline (rest) and after exposure to acute stress challenges. RESULTS: Nicotine use, but not cannabis use, was associated with blunted cortisol and cardiovascular responses to stress across both men and women. Men exhibited larger cortisol responses to stress than women. Co-users had significantly larger stress-related increases in cannabis craving than cannabis-only users. Cannabis users reported smaller increases in anxiety during stress than cannabis non/light-users, and both male nicotine-only users and male cannabis-only users experienced significantly smaller increases in stress than their non/light-user control counterparts. CONCLUSIONS: This study replicates and extends earlier research on the impacts of sex and nicotine use on stress responses, and it provides novel findings suggesting that when co-used with nicotine, cannabis use may not confer additional alterations to physiological nor subjective responses to stress. Co-use, however, was associated with enhanced stress-related craving for cannabis.

Task choice shields against incidental affective influences on effort-related cardiovascular response.

In an attempt to integrate theorizing on action shielding with affective influences on effort-related cardiovascular response, an experiment with N = 115 university students (90% women) tested whether working on a task by personal choice versus external assignment moderates the effect of happy versus sad background music on effort-related cardiovascular response during task performance. We predicted strong action shielding and low receptivity for incidental affective influences when participants could ostensibly choose the task to be performed. Given the difficult nature of the task, we thus expected strong effort-related cardiovascular responses due to high commitment when the task was chosen. By contrast, for assigned-task participants, we expected high receptivity for incidental affective influences and thus predicted strong cardiovascular reactivity when they were exposed to happy music but low responses due to disengagement when they were exposed to sad music. Effects on responses of cardiac pre-ejection period, systolic blood pressure, and heart rate confirmed our effort-related predictions. Apparently, personal choice of a task can immunize individuals against incidental affective influences on resource mobilization.

Effect of childhood maltreatment on cardiovascular response habitation to repeated psychosocial stress.

Childhood maltreatment as an early-life stress leads to cardiovascular stress response dysregulation manifested by either exaggerated or blunted stress responses. However, little is known how childhood maltreatment affects cardiovascular response habituation to recurrent stress, which implicated in the long-term health effects of chronic stress. The scale of Childhood Trauma Questionnaire (CTQ) was administered to 192 healthy undergraduates who underwent continuous cardiovascular monitoring [heart rate (HR), blood pressure (BP), cardiac output (CO) and total peripheral resistance (TPR)] while facing two consecutive psychosocial stress exposures (public speaking tasks). Results showed that childhood maltreatment was negatively associated with HR and CO reactivity to the first stress exposure and HR reactivity to the second stress exposure. Even after controlling for depression symptoms, both high and low childhood maltreatment groups (upper and lower 27% of total CTQ scores) exhibited HR and CO response habituation to repeated stress exposures, but high childhood maltreatment group showed blunted HR and CO reactivity to the first stress exposure compared with low childhood maltreatment group. These findings suggest that the observed cardiovascular response habituation to repeated stress following initial blunted (i.e., inadequate) reactivity among individuals with high childhood maltreated experiences might be maladaptive, which would lead to cardiovascular disease risk.

Exaggerated exercise pressor reflex in male UC Davis type 2 diabetic rats is due to the pathophysiology of the disease and not aging.

Introduction: Studies in humans and animals have found that type 2 diabetes mellitus (T2DM) exaggerates the blood pressure (BP) response to exercise, which increases the risk of adverse cardiovascular events such as heart attack and stroke. T2DM is a chronic disease that, without appropriate management, progresses in severity as individuals grow older. Thus, it is possible that aging may also exaggerate the BP response to exercise. Therefore, the purpose of the current study was to determine the effect of the pathophysiology of T2DM on the exercise pressor reflex independent of aging. Methods: We compared changes in peak pressor (mean arterial pressure; ΔMAP), BP index (ΔBPi), heart rate (ΔHR), and HR index (ΔHRi) responses to static contraction, intermittent contraction, and tendon stretch in UCD-T2DM rats to those of healthy, age-matched Sprague Dawley rats at three different stages of the disease. Results: We found that the ΔMAP, ΔBPi, ΔHR, and ΔHRi responses to static contraction were significantly higher in T2DM rats (ΔMAP: 29 ± 4 mmHg; ΔBPi: 588 ± 51 mmHg•s; ΔHR: 22 ± 5 bpm; ΔHRi: 478 ± 45 bpm•s) compared to controls (ΔMAP: 10 ± 1 mmHg, p < 0.0001; ΔBPi: 121 ± 19 mmHg•s, p < 0.0001; ΔHR: 5 ± 2 bpm, p = 0.01; ΔHRi: 92 ± 19 bpm•s, p < 0.0001) shortly after diabetes onset. Likewise, the ΔMAP, ΔBPi, and ΔHRi to tendon stretch were significantly higher in T2DM rats (ΔMAP: 33 ± 7 mmHg; ΔBPi: 697 ± 70 mmHg•s; ΔHRi: 496 ± 51 bpm•s) compared to controls (ΔMAP: 12 ± 5 mmHg, p = 0.002; ΔBPi: 186 ± 30 mmHg•s, p < 0.0001; ΔHRi: 144 ± 33 bpm•s, p < 0.0001) shortly after diabetes onset. The ΔBPi and ΔHRi, but not ΔMAP, to intermittent contraction was significantly higher in T2DM rats (ΔBPi: 543 ± 42 mmHg•s; ΔHRi: 453 ± 53 bpm•s) compared to controls (ΔBPi: 140 ± 16 mmHg•s, p < 0.0001; ΔHRi: 108 ± 22 bpm•s, p = 0.0002) shortly after diabetes onset. Discussion: Our findings suggest that the exaggerated exercise pressor reflex and mechanoreflex seen in T2DM are due to the pathophysiology of the disease and not aging.