Heart Rate Responses Research Articles

Pupil contagion variation with gaze, arousal, and autistic traits

Pupillary contagion occurs when one’s pupil size unconsciously adapts to the pupil size of an observed individual and is presumed to reflect the transfer of arousal. Importantly, when estimating pupil contagion, low level stimuli properties need to be controlled for, to ensure that observations of pupillary changes are due to internal change in arousal rather than the external differences between stimuli. Here, naturalistic images of children’s faces depicting either small or large pupils were presented to a group of children and adolescents with a wide range of autistic traits, a third of whom had been diagnosed with autism. We examined the extent to which pupillary contagion reflects autonomic nervous system reaction through pupil size change, heart rate and skin conductance response. Our second aim was to determine the association between arousal reaction to stimuli and degree of autistic traits. Results show that pupil contagion and concomitant heart rate change, but not skin conductance change, was evident when gaze was restricted to the eye region of face stimuli. A positive association was also observed between pupillary contagion and autistic traits when participants’ gaze was constrained to the eye region. Findings add to a broader understanding of the mechanisms underlying pupillary contagion and its association with autism.

Association of CETP Gene Polymorphisms and Haplotypes with Acute Heart Rate Response to Exercise

Polymorphisms in the cholesteryl ester transfer protein (CETP) gene are known to be strongly associated with increased cardiovascular risk, primarily through their effects on the lipid profile and consequently on atherosclerotic risk. The acute heart rate response (AHRR) to physical activity is closely related to individual cardiovascular health. This study aimed to investigate the effect of CETP gene polymorphisms on AHRR. Our analysis examines the association of five single nucleotide polymorphisms (SNPs; rs1532624, rs5882, rs708272, rs7499892, and rs9989419) and their haplotypes (H) in the CETP gene with AHRR in 607 people from the Hungarian population. Individual AHRR in the present study was assessed using the YMCA 3-min step test and was estimated as the difference between resting and post-exercise heart rate, i.e., delta heart rate (ΔHR). To exclude the direct confounding effect of the CETP gene on the lipid profile, adjustments for TG and HDL-C levels, next to conventional risk factors, were applied in the statistical analyses. Among the examined five SNPs, two showed a significant association with lower ΔHR (rs1532624—Cdominant: B = −8.41, p < 0.001; rs708272—Gdominant: B = −8.33, p < 0.001) and reduced the risk of adverse AHRR (rs1532624—Cdominant: OR = 0.44, p = 0.004; rs708272—Gdominant: OR = 0.43, p = 0.003). Among the ten haplotypes, two showed significant association with lower ΔHR (H3—CAGCA: B = −6.81, p = 0.003; H9—CGGCG: B = −14.64, p = 0.015) and lower risk of adverse AHRR (H3—CAGCA: OR = 0.58, p = 0.040; H9—CGGCG: OR = 0.05, p = 0.009) compared to the reference haplotype (H1—AGACG). Our study is the first to report a significant association between CETP gene polymorphisms and AHRR. It also confirms that the association of the CETP gene with cardiovascular risk is mediated by changes in heart rate in response to physical activity, in addition to its effect on lipid profile.

Identification of heart rate dynamics during treadmill and cycle ergometer exercise: the role of model zeros and dead time

Background The response of heart rate to changes in exercise intensity is comprised of several dynamic modes with differing magnitudes and temporal characteristics. Investigations of empirical identification of dynamic models of heart rate showed that second-order models gave substantially and significantly better model fidelity compared to the first order case. In the present work, we aimed to reanalyse data from previous studies to more closely consider the effect of including a zero and a pure delay in the model. Methods This is a retrospective analysis of 22 treadmill (TM) and 54 cycle ergometer (CE) data sets from a total of 38 healthy participants. A linear, time-invariant plant model structure with up to two poles, a zero and a dead time is considered. Empirical estimation of the free parameters was performed using least-squares optimisation. The primary outcome measure is model fit, which is a normalised root-mean-square model error. Results A model comprising parallel connection of two first-order transfer functions, one with a dead time and one without, was found to give the highest fit (56.7 % for TM, 54.3 % for CE), whereby the non-delayed component appeared to merely capture initial transients in the data and the part with dead time likely represented the true dynamic response of heart rate to the excitation. In comparison, a simple first-order model without dead time gave substantially lower fit than the parallel model (50.2 % for TM, 47.9 % for CE). Conclusions This preliminary analysis points to a linear first-order system with dead time as being an appropriate model for heart rate response to exercise using treadmill and cycle ergometer modalities. In order to avoid biased estimates, it is vitally important that, prior to parameter estimation and validation, careful attention is paid to data preprocessing in order to eliminate transients and trends.

Hormones, autonomic nervous system activity, and criminal behavior

ABSTRACT Evidence that hormones and autonomic nervous system activity exert a joint influence on antisocial behavior suggests that they may work together to explain risk for criminal behavior. Thus, the current study explored the interactive effects of hormones (testosterone, cortisol) and ANS activity (heart rate, skin conductance) on impulsive and violent criminal behavior in a large sample of university students (n = 495). Initial analyses found positive direct associations between impulsive and violent crime and both testosterone and cortisol and a negative direct association between heart rate reactivity and impulsive and violent crime. Subsequent analyses revealed a statistically significant interaction between testosterone and heart rate in association with impulsive and violent criminal behavior. The positive association between testosterone and crime became statistically significant at −.29 standard deviations below the mean (HR = 76.44) and grew stronger as heart rate decreased from this point. The interaction between testosterone and heart rate remains statistically significant after the inclusion of controls for constructs that feature prominently in contemporary criminological theories. Other interactions between hormones and ANS activity were present but were not consistent across alternative model specifications.

Decoding Exercise Heart Rate Responses Among Patients with Heart Failure.

Decoding Exercise Heart Rate Responses Among Patients with Heart Failure.

Exploring the Impact of Bubble Type on Sensory Stimulation in Drinks

This study explores the impact of various types of carbonation on sensory stimulation in the mouth, salivary secretion and the neurotransmitter substance P (SP), as well as body responses such as heart rate (HR) and Galvanic Skin Response (GSR). Three types of carbonation (one made using a soda machine, another carbonated with a gasifier, and the last commercial sparkling water) were used to produce different bubbles resulting in distinct sensory characteristics assessed by a trained panel. The impact of carbonation was measured by recording changes in salivary flow rate, SP levels, salivary secretory immunoglobulin A (SIgA), HR, and GSR in fifteen healthy participants. The results showed that the bubble type only affected the sensory perception of carbonation. Regardless of bubble type, carbonation increased salivary flow rate and SP values, HR and GSR. These characteristics are being sought to improve treatments for dysphagia or dry mouth. Therefore, these findings highlight the potential therapeutic application of carbonation in these situations.

Self-blame, posttraumatic stress, and cardiovascular reactivity among sexual trauma survivors.

Although trauma is closely linked with hyperarousal and cardiovascular health, little research has examined the effects of posttraumatic stress symptoms (PTSS) on cardiovascular reactivity to trauma reminders among sexual trauma survivors. One type of negative appraisal after trauma, self-blame, is common after sexual trauma, but its relation to cardiovascular reactivity is unknown. The present study aimed to examine the influence of both PTSS and self-blame on blood pressure and heart rate (HR) reactivity to a trauma reminder. Cardiovascular reactivity was measured before, during, and after a laboratory-based sexual trauma reminder among 72 young adult women who have experienced sexual trauma. Higher PTSS predicted lower diastolic blood pressure (DBP) reactivity during the trauma reminder. Higher levels of self-blame predicted higher HR and systolic blood pressure (SBP) reactivity during and after the trauma reminder. Overall, these findings suggest that survivors of sexual trauma with higher levels of PTSS experience a blunting reaction of DBP when exposed to trauma reminders, as opposed to a more typical cardiovascular stress reaction that may elevate and then extinguish to baseline levels. Meanwhile, individuals with higher levels of self-blame have heightened cardiovascular SBP and HR responses during trauma reminders that do not return to baseline levels, perhaps due to self-blame leading individuals to be more 'on guard' to prevent future threats. Longitudinal studies are needed to explore the potential long-term cardiovascular impacts of heightened self-blame and PTSS and their associated cardiovascular reactivity patterns.

A quasi-experimental study on the energy expenditure, exercise intensity, and rating of perceived exertion of a male bodybuilding posing training.

This study aimed to evaluate the intensity of posing training in male bodybuilders by comparing it to vigorous intensity parameters and examining the effects of stimulant usage and preparation phases. Specifically, it compared posing training to established vigorous intensity benchmarks using Metabolic Equivalents (METs) and heart rate (HR) responses and assessed differences between athletes using stimulants versus those not using stimulants, as well as during peak week versus other preparation phases. Fifteen male bodybuilding athletes (mean age: 32.07 ± 7.82 years; mean body mass: 92.89 ± 9.06 kg; mean height: 1.76 ± 0.05 m; mean BMI: 29.78 ± 2.24 kg/m²) completed four compulsory posing sets. Findings demonstrated that posing training can be classified as vigorous intensity using METs (mean difference of -0.50 METs, p = 0.067, ES = -0.51) and maximum HR (mean difference of 14.55 bpm, p = 0.009, ES = 0.79) compared to the established values of 6.0 METs and 77% vigorous intensity of %HRmax. Additionally, athletes using stimulants exhibited higher ratings of perceived exertion (RPE) of 2.20 arbitrary units (p = 0.008) and maximum HR (mean difference of 24.37 bpm, p = 0.005, ES = 0.79) compared to those not using stimulants. During peak week, athletes showed higher RPE of 2.38 arbitrary units (p = 0.004) and maximum HR (mean difference of 14.55 bpm, p = 0.009, ES = 0.79) compared to other preparation phases. These results indicate that bodybuilding posing training meets the criteria for vigorous exercise intensity and that stimulant use and peak week significantly affect physiological responses and perceived exertion.

CITED4 gene therapy protects against maladaptive cardiac remodeling after ischemia/reperfusion injury in mice

Cardiac signaling pathways functionally important in the heart's response to exercise often protect the heart against pathologic stress, potentially providing novel therapeutic targets. However, it is important to determine which of these pathways can be feasibly targeted in vivo. Transgenic overexpression of exercise-induced CITED4 has been shown to protect against adverse remodeling after ischemia/reperfusion injury (IRI). Here we investigated whether somatic gene transfer of CITED4 in a clinically relevant time frame could promote recovery after IRI. Cardiac CITED4 gene delivery via intravenous AAV9 injections in wild type mice led to a ∼3-fold increase in cardiac CITED4 expression. After four weeks, CITED4-treated animals developed physiologic cardiac hypertrophy without adverse remodeling. In IRI, delivery of AAV9-CITED4 after reperfusion resulted in a 6-fold increase in CITED4 expression one week after surgery, as well as reduced apoptosis, fibrosis, and inflammatory markers, culminating in a smaller scar and improved cardiac function eight weeks after IRI, compared to control mice receiving AAV9-GFP. Somatic gene transfer of CITED4 induced a phenotype suggestive of physiologic cardiac growth and mitigated adverse remodeling after ischemic injury. These studies support the feasibility of CITED4 gene therapy delivered in a clinically relevant time frame to mitigate adverse ventricular remodeling after ischemic injury.

A Descriptive Exploration of Heart Rate Response to Live Professional Irish Dance Performance.

Introduction: Research investigating the physiological demands of dance performance has documented exercise intensity and time spent in work and rest; however, available data are across limited dance genres and often use rehearsal or simulated conditions. Real-time data recorded during live performance with an audience are limited. The aim of the study is to provide a detailed description of the physiological demands of live professional Irish dance performance. Method: The entire Irish dance cast of Riverdance participated in the study (n = 24). Approval was granted by the Institutional Research Ethics Committee. Matinee and evening performances on the first day of a tour were examined in a descriptive, cross-sectional design. Heart rate (HR) monitors worn discretely under costumes recorded data every 5-seconds. Video analysis allowed calculation of time spent in work and rest. All descriptive analyses were split by role (troupe/lead) and sex (male/female). Results: Dancers worked at hard/very hard intensities (mean > 72%, peak > 91% HRmax) for ~3 minutes at a time for 3-9 individual dance numbers. There was a high variation in overall demand experienced by individual dancers due to variation in both duration and intensity of on-stage time, dependent upon their role. Mean total on-stage time was 18.18 ± 5.82 minutes, 19.43 ± 5.80 minutes, 29.71 ± 0.62 minutes, 20.00 ± 0.00 minutes for male troupe, female troupe, male lead, and female lead dancers, respectively. Recovery periods were varied in terms of duration, activity undertaken, and HR response. Conclusion: Individual dance numbers within a professional Irish dance show were high intensity for a short duration when considered in isolation, but overall physiological demand experienced by any one dancer across the entire show varied dependent upon their role and off-stage/recovery practices. Future research investigating the physiological demands of dance performance should ensure analysis accounts for the individual dancer's role and should capture the entire show duration in repeated exposures.

Influence of endogenous and exogenous hormones on the cardiovascular response to lower extremity exercise and group III/IV activation in young females.

Oral contraceptive (OC) use can increase resting blood pressure (BP) in females as well as contribute to greater activation of group III/IV afferents during upper body exercise. It is unknown, however, whether an exaggerated BP response occurs during lower limb exercise in OC users. We sought to elucidate the group III/IV afferent activity-mediated BP and heart rate responses, while performing lower extremity tasks during early and late follicular phases in young, healthy females. Females not taking OCs (NOC: n=8; age: 25±4 years) and taking OCs (OC: n=10; age: 23±2 years) completed a continuous knee extension/flexion passive stretch (mechanoreflex) and cycling exercise with sub-systolic cuff occlusion (exercise pressor reflex), which was followed by a two-minute post-exercise circulatory occlusion (PECO) (metaboreflex). Data collection occurred on two occasions: once during the early follicular phase (days 1-4) and once during the late follicular phase (days 10-14) of their menstrual cycle (NOC), or during the placebo and active pill phases (OC). Resting mean arterial BP and heart rate were not different between phases in NOC and OC participants (p>0.05). Hemodynamic responses to metaboreflex, mechanoreflex, and collective exercise pressor reflex activation were not different between phases in both groups (p>0.05). In conclusion, although OCs are known to increase BP at rest, our findings indicate that neither endogenous nor exogenous (OC) sex hormones modulate BP during large, lower-limb muscle exercise, with or without group III/IV afferent activation in young, healthy females.

Sigmoidal heart rate response pattern during exercise in patients with chronic heart failure.

Detailed heart rate (HR) response patterns during exercise in patients with heart failure and sinus rhythm remains uncertain. We screened consecutive heart failure patients who underwent cardiopulmonary exercise tests at a large academic center from November 2013 to July 2023. HR response during exercise was statistically classified using logistic differential equation models. A total of 99 patients were included. Of them, 75 patients were assigned to "sigmoidal pattern" and the other 24 to "exponential pattern". Patients with the sigmoidal pattern were older and exhibited higher plasma B-type natriuretic peptide levels. Increases in HR and VO2/kg up to the anaerobic threshold level were not different between both patterns. However, beyond the threshold, the sigmoidal pattern group showed no further increase in HR and significantly lower VO2/kg than their counterparts (interactions for p<0.001). HR response during exercise in patients with heart failure and sinus rhythm was categorized into two unique groups: sigmoidal and exponential patterns. More detailed clarification of the sigmoidal pattern, potentially indicating sinus node dysfunction, should offer new clinical insights for chronotropic incompetence.

Cardiovascular autonomic and peripheral sensory neuropathy in women with obesity.

A higher incidence of neural dysfunction in people with obesity has been described. We determined the prevalence of neuropathic lesions in obese women and evaluated their potential association with anthropometric and laboratory parameters. In our cross-sectional study, we enrolled female patients with obesity and without diabetes before obesity treatment. Voluntary female subjects were controls with a normal body mass index (BMI). Autonomic function was assessed by Ewing's cardiovascular reflex tests, while comprehensive peripheral neuropathic assessments were conducted utilizing the Neurometer®, Tiptherm®, Monofilament®, and Rydel-Seiffer tuning fork tests. Sudomotor function was assessed by the Neuropad®-test. Body composition was examined using the InBody 770. 71 patients (mean ± SD; age: 36.1 ± 8.3 years; BMI: 40.2 ± 8.5 kg/m2) and 36 controls (age: 36.4 ± 13.3 years; BMI: 21.6 ± 2.1 kg/m2) were enrolled. Patients had significantly higher systolic (patients vs. controls; 137.5 ± 16.9 vs. 114.6 ± 14.8 mmHg, p<0.001) and diastolic (83.0 ± 11.7 vs.69.8 ± 11.2 mmHg, p<0.001) blood pressure compared to controls. Among autonomic tests, only the heart rate response to Valsalva maneuver (Valsalva-ratio) revealed significant impairment in patients (1.4 ± 0.2 vs. 1.7 ± 0.4, p<0.001). Neurometer® at the median nerve revealed increased current perception threshold (CPT) values at all stimulating frequencies in patients (CPT at 2000Hz: 204.6 ± 70.9 vs. 168.1 ± 66.9, p=0.013; 250Hz: 84.4 ± 38.9 vs. 56.5 ± 34.8, p<0.001; CPT at 5Hz: 58.5 ± 31.2 vs 36.9 ± 29.1, p<0.001). The Rydel-Seiffer tuning fork test has revealed a significant impairment of vibrational sensing on the lower limb in patients (right hallux: 6.8 ± 0.9 vs. 7.4 ± 0.8, p=0.030; left hallux: 6.9 ± 0.8 vs. 7.3 ± 0.9, p=0.029). The Neuropad® testing showed a significant impairment of sudomotor function in women with obesity. A negative correlation was found in patients between BMI and the 25-hydroxy-D3/D2-vitamin levels (r=-0.41, p=0.00126) and a positive correlation between the BMI and resting systolic blood pressure (r=0.26, p=0.0325). Peripheral sensory neuronal and sudomotor function impairments were detected in female patients with obesity compared to the controls with normal BMI. Cardiovascular autonomic dysfunction was also revealed by the Valsalva-ratio in these patients, suggesting the presence of parasympathetic dysfunction. The negative correlation between BMI and the 25-hydroxy-D3/D2-vitamin highlights the potential deficiency of vitamin D in the population affected by obesity.

Cardiac autonomic response to acute painful stimulus in individuals with chronic neck pain: A case-control study

PurposeCharacterize heart rate and cardiac autonomic response to painful stimulus on neck pain. MethodsTwenty-five individuals with neck pain and 25 healthy subjects were included. Heart rate variability and heart rate were assessed in the conditioned pain modulation test at pretest rest, during testing and in recovery. Heart rate variability indices were obtained using linear and nonlinear methods. ResultsNo significant differences were observed between groups regarding heart rate and the linear methods (p > 0.05). However, significant difference was observed between groups regarding nonlinear methods (standard deviation of the instantaneous variability of beat-to-beat interval variability, p = 0.005) ConclusionsIndividuals with chronic neck pain showed autonomic responses similar to those of their healthy counterparts during the conditioning stimulus.

Effect of zamicastat on blood pressure and heart rate response to cold pressor test: A double-blind, randomized, placebo-controlled study in healthy subjects.

Dopamine beta-hydroxylase (DβH) inhibitors, like zamicastat, hold promise for treating pulmonary arterial hypertension. This study aimed to validate the mechanism of action of zamicastat by studying its effect on the overdrive of the sympathetic nervous system (SNS). A single-centre, prospective, double-blind, randomized, placebo-controlled, crossover study evaluated the effect of 400 mg zamicastat in 22 healthy male subjects. Cold pressor test (CPT) was performed at screening and each treatment period on Days -1 and 10. Plasma and 24 h-urine levels of dopamine (DA), epinephrine (EPI) and norepinephrine (NE), and plasma DβH activity, were measured. Compared to placebo, zamicastat showed a - 4.62 mmHg decrease in systolic blood pressure during the cold stimulus vs. rest phases on Day 10 of CPT (P = .020). Zamicastat decreased mean arterial pressure response to cold stimulus during CPT (-2.62 mmHg; P = .025). At Day 10, zamicastat significantly increased plasma DA, before CPT (12.63 ng/L; P = .040) and after CPT (19.22 ng/L; P = .001) as well as the estimated plasma EPI change from baseline after CPT (P = .040). Inhibition of plasma DβH activity ranged from 19.8% to 25.0%. At Day 10, significant reductions in 24-h urinary excretion of EPI (P = .002) and NE (P = .001) were observed. Zamicastat Cτ geometric mean ± GSD ranged from 45.86 ± 1.46 ng/mL on Day 3 to 58.64 ± 1.52 ng/mL on Day 10, with moderate inter-individual variability (CV: 32.6%-36.6%). Steady state was already achieved on Day 6. Our results demonstrated the effect of zamicastat on the overdrive sympathetic response to cold stimulus, confirming its potential as SNS modulator.

Assessment of cardiorespiratory fitness in Chinese patients with early to mid-stage Parkinson’s disease

Purpose To evaluate cardiorespiratory fitness in patients with early to mid-stage Parkinson’s disease by cardiopulmonary exercise test (CPET) on a stationary cycle ergometer. Methods To compare the differences in each index of the cardiopulmonary exercise test between the two groups of subjects; general data such as disease duration, medication use and exercise habits were also collected. Results (1) Finally, 36 Parkinson’s disease patients and 12 healthy controls successfully completed the cardiopulmonary exercise test without any adverse events. (2) The V’O2peak, Metspeak, RERpeak, MVVpeak, Wpeak, HRpeak, HRpeak/pre, percentage of HRR-1 min decay > 12 bpm, SBPpeak in the Parkinson’s disease group were lower than those in the control group (p < .05, each). Detailed data: V’O2peak (15.7 ± 4.5vs21.5 ± 3.6 ml/kg/min, p < .01), Metspeak (4.5 ± 1.3 vs 6.1 ± 1.0, p < .01), RERpeak (1.04 ± 0.10 vs 1.15 ± 0.10, p = .001), MVVpeak (37.22 ± 11.58 vs 53.00 ± 16.85L/min, p = .009), Wpeak (49.17 ± 29.72 vs 49.17 ± 29.72W, p < .01), HRpeak (111.08 ± 16.67 vs 111.08 ± 16.67bpm, p < .01), HRpeak/pre (71.19 ± 10.06 vs 96.00 ± 21.13, p = .002), percentage of HRR-1min decay > 12bpm (33.3% vs 100%, p < .01), systolic blood pressure (155.81 ± 31.83 vs 175.83 ± 17.84 mmHg, p = .01). (3) Divided Parkinson’s disease patients into high V’O2peak group (V’O2peak ≥ 15 mL/kg/min) and low V’O2peak group (V’O2peak < 15 mL/kg/min). The age of patients, Hoehn–Yahr grade and incidence of symptom fluctuation in high V’O2peak group were lower (p < .05, respectively), percentage of males and percentage of HRR-1 min decay > 12 bpm were higher (p < .05, respectively); p < .05 is considered a statistically significant difference. Detailed data: age of patients(61.05 ± 6.93 vs 68.57 ± 7.99 years, p = .005), Hoehn–Yahr grade(1.75 ± 0.48 vs 2.18 ± 0.64, p = .028), incidence of symptom fluctuation (59.1 vs 92.9%, p = .03), percentage of males (77.7 vs 42.9%, p = .041), percentage of HRR-1 min decay > 12 bpm (50 vs 7.1%, p = .008). Conclusions Cardiopulmonary exercise test was safe to perform and the cardiorespiratory fitness is significantly reduced in patients with early and middle stage Parkinson’s disease. Patients with Parkinson’s disease presented blunted heart rate and systolic blood pressure responses to exercise test. Females, older age, fluctuating symptoms, high H-Y staging and higher activities of daily living may be associated with lower oxygen uptake.

The heart rate response to the 6-min walk test in atrial fibrillation patients with or without beta-blockers: Referring to patients with sinus rhythm.

The aim was to evaluate the effect of beta-blockers (BB) on the response of heart rate (HR) to 6-min walk test (6MWT) in atrial fibrillation (AF) and whether the AF patients treated with BB have a similar HR response to 6MWT as the AF and sinus rhythm (SR) patients without BB treatment at the same resting HR level. The before-after study involving 74 AF patients was to evaluate the effect of BB treatment (pre-BB and with BB). The comparison study included 74 BB-treated AF patients (with BB), 74 matched AF patients without BB (no BB), and 74 SR patients. The percentage increase amplitude of HR (HR-PIA) in 6MWT was calculated: [(the exercise HR - the resting HR)/(the resting HR)] × 100%. The before-after study showed that BB treatment decreased the resting and mean exercise HR (98.6 ± 15.2 vs. 85.5 ± 11.2 bpm and 121.3 ± 17.3 vs. 109.0 ± 16.7 bpm) during 6MWT. The comparison study demonstrated that against the SR, the AF with BB and no BB groups have higher mean exercise HR-PIA (28.2 ± 17.1% and 22.0 ± 9.6%, vs. 6.9 ± 3.7%) when their resting HR is similar. Moreover, the mean exercise HR-PIA was also significantly higher in the with BB group than in the no BB group. In AF patients with relatively higher resting HR, BB treatment could decrease the resting and exercise HR during 6MWT. However, BB treatment could not effectively attenuate the exercise HR rise as compared with AF without BB treatment, even with similar resting HR levels.

Clinical Pharmacogenetics Implementation Consortium Guideline (CPIC)for CYP2D6, ADRB1, ADRB2, ADRA2C, GRK4, and GRK5 Genotypes and Beta-Blocker Therapy.

Beta-blockers are widely used medications for a variety of indications, including heart failure, myocardial infarction, cardiac arrhythmias, and hypertension. Genetic variability in pharmacokinetic (e.g., CYP2D6) and pharmacodynamic (e.g., ADRB1, ADRB2, ADRA2C, GRK4, GRK5) genes have been studied in relation to beta-blocker exposure and response. We searched and summarized the strength of the evidence linking beta-blocker exposure and response with the six genes listed above. The level of evidence was high for associations between CYP2D6 genetic variation and both metoprolol exposure and heart rate response. Evidence indicates that CYP2D6 poor metabolizers experience clinically significant greater exposure and lower heart rate in response to metoprolol compared with those who are not poor metabolizers. Therefore, we provide therapeutic recommendations regarding genetically predicted CYP2D6 metabolizer status and metoprolol therapy. However, there was insufficient evidence to make therapeutic recommendations for CYP2D6 and other beta-blockers or for any beta-blocker and the other five genes evaluated (updates at www.cpicpgx.org).

Apnea or normal breathing during repeated high-intensity swimming enhance sprint efficiency and which metabolic disorder?

The aim of this study was to investigate the effect of normal breath and apnea swimming on acid-base balance, physiological responses and performance during high-intensity interval training in swimming. Sixteen swimmers completed 6×50 m intervals of freestyle swimming with normal breath and apnea at maximum intensity, with 1 minute rest. Capillary blood gases (pH, PCO<inf>2</inf>, PO<inf>2</inf>, HCO<inf>3</inf>, Hct, Hb) were collected at four (4) measurement time points: 1) at rest once; 2) at rest just after the 3rd repetition; 3) at finish; and 4) at 10 min of recovery. Heart rate (HR) during swimming, lactate acid (La) concentration and swimming time (t<inf>50</inf>) were measured. Our study showed uncompensated metabolic acidosis due to increased lactic acidosis in both breathing conditions, more pronounced in apnea, and faster swimming times in apnea without different heart rate responses. Apnea during repetitive high intensity long distance interval 50 m freestyle swimming causes uncompensated metabolic acidosis but improves sprint performance.

Blunted brachial blood flow velocity response to acute mental stress in PTSD females.

Post-traumatic stress disorder (PTSD) is associated with increased cardiovascular disease (CVD) risk. Compared with males, females are twice as likely to develop PTSD after trauma exposure, and cardiovascular reactivity to stress is a known risk factor for CVD. We aimed to examine hemodynamic responses to acute mental stress in trauma-exposed females with and without a clinical diagnosis of PTSD. We hypothesized that females with PTSD would have higher heart rate (HR), blood pressure (BP), and lower blood flow velocity (BFV) responsiveness compared with controls. We enrolled 21 females with PTSD and 21 trauma-exposed controls. We continuously measured HR using a three-lead electrocardiogram, BP using finger plethysmography, and brachial BFV using Doppler ultrasound. All variables were recorded during 10 min of supine rest, 5 min of mental arithmetic, and 5 min of recovery. Females with PTSD were older, and had higher BMI and higher resting diastolic BP. Accordingly, age, BMI, and diastolic BP were covariates for all repeated measures analyses. Females with PTSD had a blunted brachial BFV response to mental stress (time × group, p = 0.005) compared with controls, suggesting greater vasoconstriction. HR and BP responses were comparable. In conclusion, our results suggest early impairment of vascular function in premenopausal females with PTSD.