Greater Increase In Heart Rate Research Articles

Autonomic Effects of Pulsed Field vs Thermal Ablation for Treating Atrial Fibrillation: Subanalysis of ADVENT

BackgroundAutonomic denervation is an ancillary phenomenon during thermal ablation of atrial fibrillation (AF), that may have synergistic effects on symptomatic improvement and long-term freedom from AF. Pulsed field ablation (PFA), a nonthermal ablation modality, was noninferior to thermal ablation in treating AF; however, PFA’s relative myocardial selectivity may minimize autonomic effects. ObjectivesThis study sought to compare heart rate (HR) and heart rate variability (HRV) metrics as markers of autonomic function after ablation using PFA vs thermal ablation. MethodsADVENT was a randomized pivotal study comparing PFA (pentaspline catheter) with thermal ablation (radiofrequency [RF] or cryoballoon [CB]) for treating paroxysmal AF. Baseline HR was acquired from a pre-ablation 12-lead electrocardiogram, whereas follow-up HRs, as well as HRV (standard deviation of all normal to normal RR intervals, standard deviation of 5-minute average RR intervals) metrics, were derived from 72-hour Holter monitors at 6 and 12 months. ResultsThis study included 379 paroxysmal AF patients undergoing PFA (n = 194) or thermal ablation (n = 185; n = 102 RF, n = 83 CB) completing 6- and 12-month Holter monitoring. Compared with PFA, thermal patients had significantly greater increases in HR from baseline to 6 months (ΔHR; 10.1 vs 5.9 beats/min; P = 0.02) and 12 months (ΔHR; 8.8 vs 5.2 beats/min; P = 0.03). This increase in HR at 6 and 12 months was similar between CB and RF (P = 0.94 and 0.83, respectively). HRV, both standard deviation of all normal to normal RR intervals and standard deviation of 5-minute average RR intervals, were significantly lower at both 6 and 12 months after thermal ablation compared with PFA (P < 0.01). ConclusionsPFA’s effect on the autonomic nervous system was attenuated compared with thermal ablation. Whether this affects long-term freedom from AF or symptomatic bradycardia/pauses after AF ablation requires further study.

Maternal Injection with Dexamethasone Results in Female-Biased Autonomic Dysregulation in Rat Offspring

Autonomic dysfunction is an underlying risk factor for cardiovascular disease (CVD). Maternal injection of the synthetic GC dexamethasone (DEX) during the last 4 days of gestation results in female-biased increases in stress-responsive pressor (MAP), heart rate (HR) and altered heart rate variability (HRV) in adult rat offspring, suggesting a role for GC-mediated programming of autonomic function. The present study used pharmacological antagonists for adrenergic (SYM) or cholinergic (PS) receptors to investigate the degree to which changes in SYM or PS activity underlie the autonomic dysfunction in offspring of dams injected with DEX during late gestation. Naïve breeders were injected with DEX (0.4mg/kg/day, s.c.) or vehicle (hydroxypropyl beta cyclodextrin; Veh) on gestation days 18-21. Radiotelemetry was used in adult offspring for recording HR, MAP, and HRV (root mean square of successive differences: RMSSD). At 10-11 weeks rats were randomly assigned to receive SYM antagonists, α-adrenoceptor (prazosin; 0.5mg/kg, i.p.) + β-adrenoceptor (atenolol; 1mg/kg, i.p.), a PS antagonist (homatropine methylbromide; 0.2mg/kg, i.p), or saline (SAL, i.p.). Evaluations were made over 20 min following injection and then during a 20 min restraint. Females were tested on diestrus. In utero DEX exposure resulted in significantly lower RMSSD, an index of vagal tone, in DEX-exposed females and males. PS blockade significantly reduced RMSSD in Veh-, but not DEX-exposed female offspring. SYM blockade did not influence RMSSD in females. In males, PS blockade reduced in RMSSD in both DEX- and Veh-exposed offspring. SYM blockade only reduced RMSSD in males exposed to DEX. Area under the curve (AUC) analysis revealed that in female offspring, SYM blockade resulted in a greater reduction in HR in DEX-exposed offspring, compared to Veh (DEX-SYM: −220 bpm vs. DEX-SAL; Veh-SYM: −197 bpm vs. VEH-SAL) and during restraint (DEX-SYM: −535 bpm vs. DEX-SAL; Veh-SYM: −342 bpm vs. VEH-SAL). PS blockade resulted in a greater increase in HR in Veh-exposed females both following the injection (Veh-PS: −187 bpm vs. VEH-SAL; DEX-PS: −101 bpm vs. DEX-SAL) and during restraint (Veh-PS: −161 bpm vs. VEH-SAL; DEX-PS: −61 bpm vs. DEX-SAL). AUC analysis for MAP showed similar responses to those for HR with SYM blockade having a greater impact in DEX-exposed females and PS blockade having a greater effect in Veh-exposed females. By contrast, in male offspring in utero DEX exposure did not influence HR or MAP responses to SYM or PS blockade. Overall, these findings suggest that maternal DEX injections alter autonomic development primarily in in female offspring and is characterized by a shift from PS to SYM predominance. Better understanding of the mechanisms involved in this programming are important for identifying individuals at risk for CVD and development of interventional strategies for prevention of CVD. Funding: NIH U54 MH118919. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Hyperventilation in Patients with Postural Orthostatic Tachycardia Syndrome (POTS): Effects of Tidal Volume versus Hypocapnia on Heart Rate

Background: Postural Orthostatic Tachycardia Syndrome (POTS) is a chronic form of orthostatic intolerance that significantly impacts the quality of life and day-to-day functioning of patients. POTS has an estimated prevalence of about 1%, predominantly affecting females of child-bearing age. POTS is characterized by an upright increase in heart rate (HR) of ≥30 bpm, without a drop in blood pressure. POTS is associated with chronic (≥ 3 months) upright symptoms including light-headedness, blurred vision, and cognitive dysfunction. A large proportion of POTS patients also experience hyperventilation when upright. Hyperventilation reduces arterial carbon dioxide (CO2; hypocapnia) and exacerbates tachycardia in POTS. Whether the HR response is due to increased tidal volume (VT) per se or the resulting hypocapnia is unclear. Investigating the independent effects of increased VT versus hypocapnia on HR might identify possible therapeutic targets to reduce HR in patients with POTS. Objective: We aimed to characterize the separate effects of hypocapnia and VT on HR in POTS patients. Hypothesis: We hypothesize that hypocapnia and VT will independently increase HR, with hypocapnia causing the greatest increase in HR in patients with POTS. Methods: Twenty female POTS patients (32±10 years) completed supine normocapnic and hypocapnic breathing tests. To assess the effects of hypocapnia on HR, we compared hypocapnic-hyperventilation versus normocapnic-hyperventilation with constant VT. To assess the effects of VT on HR, we compared increased VT breathing versus normal breathing with constant end-tidal CO2 (ETCO2). Breath-by-breath respiratory (VT, ETCO2) and beat-to-beat hemodynamic parameters (stroke volume [SV], HR) were continuously measured. Data were analyzed with paired t-tests, and are reported as mean ± SD. Results: ETCO2 was lower ( p&lt;0.001) with similar VT during hypocapnia compared to normocapnia. Hypocapnia reduced SV (63.3±11.8 mL vs. 72.4±12.3 mL; p&lt;0.001), and increased HR (99±13 bpm vs. 81±9 bpm; p&lt;0.001). Compared to normal breathing, increased VT ( p&lt;0.001) with constant ETCO2 led to a smaller reduction in SV (72.4±12.3 mL vs. 76.0±14.3 mL; p=0.04), and increase in HR (81±9 bpm vs. 75±9 bpm; p&lt;0.001). Conclusion: Our results suggest that hypocapnia and increased VT independently reduce SV and increase HR in POTS patients. The increase in HR was greater during hypocapnia (+18 bpm) compared to increased VT (+6 bpm). Reducing hypocapnia presents an attractive therapeutic target. Disclosures: This work was supported by Standing up to POTS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Thermoregulatory Responses to Very Hot and Dry Heat Exposure: Interactions Between Age and Sex

Extreme heat events can cause mass morbidity and mortality. Older adults are more susceptible to the adverse effects of heat. Additionally, sex is known to independently influence the physiological responses to heat stress. However, less is known regarding the interaction between age and sex on thermoregulation. Purpose: This study investigated differences in thermoregulatory responses between males and females in older and younger individuals exposed to a hot and dry environment with accompanying activities of daily living. Methods: Twenty older (70 ± 4 yrs) and twenty younger (29 ± 5 yrs) adults (10 males and 10 females per group) were exposed to 3-hours of ambient heating, replicating peak environmental conditions during the 2018 Los Angeles heat wave (47 °C, 15% relative humidity). Participants performed seven 5-minute periods of light exercise (≍3 METS; metabolic heat production: 2.99 ± 0.33 W/kg) dispersed throughout the heat exposure to simulate heat generation associated with activities of daily living. Participants ingested 3 mL/kg/hr of tap-temperature water throughout the trial. Core temperature, skin temperature, and heart rate changes were assessed from pre-post heat exposure. Whole-body sweat rate and forearm blood flow changes were indexed to changes in core temperature. Data were analyzed using a two-way ANOVA (Age x Sex) Results: Delta core temperature was greater in older individuals (males: 1.43 ± 0.47°C, females: 1.31 ± 0.39°C) than in younger (males: 0.83 ± 0.22°C, females: 0.53 ± 0.24°C, p&lt;0.001) but there was no difference between sex (p = 0.063) nor was there an interaction (p = 0.423). There was an interaction of age and sex on delta heart rate (p = 0.019). Older females (32 ± 9 bpm) had greater increases in heart rate than older males (18 ± 8 bpm), younger males (18 ± 6 bpm), and younger females (18 ± 12 bpm, p ≤ 0.009 for all comparisons). There was no effect of age (p = 0.529), sex (p = 0.670), or interaction (p = 0.422) on delta skin temperature. There was an interaction between age and sex for whole-body sweat loss (WBSL) indexed to changes in core temperature and body surface area (p = 0.009). Younger females (1688 ± 685 mL/m2/°C) had greater WBSL than older females (612 ± 211 mL/m2/°C, p &lt; 0.0001), older males (694 ± 327 mL/m2/°C, p &lt; 0.0001), and younger males (1038 ± 282 mL/m2/°C, p &lt; 0.0001). There was a main effect of sex (p = 0.003) and age (p &lt; 0.0001), but no interaction (p = 0.152) on delta forearm blood flow indexed to changes in core temperature (older males: 116 ± 67 mL/min/°C, older females: 194 ± 73 mL/min/°C, younger males: 263 ± 72 mL/min/°C, younger females: 468 ± 243 mL/min/°C). Conclusion: These data suggest that many thermoregulatory responses to heat stress are influenced by the interaction between age and sex. Supported by NIH R01AG069005 (CGC). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Features of vegetative adaptation to educational activities of primary school children

Purpose. To study the functional state of the autonomic nervous system (ANS), which is involved in the formation of adaptation processes in schoolchildren with different physiological abilities. Material and methods. Three groups of junior schoolchildren were examined: 1st – intellectually gifted children, selected based on the results of specialized scales and tests; 2nd – children with high sports/physical abilities; 3rd (control) – schoolchildren with good academic performance and sports/physical abilities. The functional state of the ANS of children was studied using cardiointervalography. Results. The dynamics of the mode indicators, mode amplitude, variation range, and tension index of regulatory systems (IN) indicated that in group 1 the activity of the sympathetic influences of the ANS predominated, the ratio IN2/IN1 showed hypersympathicotonic reactivity. In group 2, the IN values corresponded to normotonic values. The majority of children in groups 2 and 3 had a normal type of autonomic response. The greatest increase in heart rate and systolic blood pressure during orthostasis was observed in group 1. Conclusion. Multidirectional changes in systolic blood pressure and an increase in diastolic blood pressure of varying degrees of severity were established in children of the study groups, which indicates the heterogeneous nature of vascular reactions to orthostasis. The rhythmogram indicators in group 1 are characterized by the predominance of the activity of the sympathetic influences of the ANS. The identified imbalance in the functional activity of the ANS in children of the 1st group indicates the tension of adaptation processes.

The combined effects of acidification and acute warming on the embryos of Pacific herring (Clupea pallasii)

Anthropogenic climate change is projected to affect marine ecosystems by challenging the environmental tolerance of individuals. Marine fishes may be particularly vulnerable to emergent climate stressors during early life stages. Here we focus on embryos of Pacific herring (Clupea pallasii), an important forage fish species widely distributed across the North Pacific. Embryos were reared under a range of temperatures (10-16°C) crossed with two pCO2 levels (600 and 2000 μatm) to investigate effects on metabolism and survival. We further tested how elevated pCO2 affects critical thermal tolerance (CTmax) by challenging embryos to short-term temperature fluctuations. Experiments were repeated on embryos collected from winter and spring spawning populations to determine if spawning phenology corresponds with different limits of environmental tolerance in offspring. We found that embryos could withstand acute exposure to 20°C regardless of spawning population or incubation treatment, but that survival was greatly reduced after 2-3 hours at 25°C. We found that pCO2 had limited effects on CTmax. The survival of embryos reared under chronically warm conditions (12°, 14°, or 16°C) was significantly lower relative to 10°C treatments in both populations. Oxygen consumption rates (MO2) were also higher at elevated temperatures and pCO2 levels. However, heart contraction measurements made 48 hours after CTmax exposure revealed a greater increase in heart rate in embryos reared at 10°C compared to 16°C, suggesting acclimation at higher incubation temperatures. Our results indicate that Pacific herring are generally tolerant of pCO2 but are vulnerable to acute temperature stress. Importantly, spring-spawning embryos did not clearly exhibit a higher tolerance to heat stress compared to winter offspring.

Influence of Fluid Ingestion on Heart Rate, Cardiac Autonomic Modulation and Blood Pressure in Response to Physical Exercise: A Systematic Review with Meta-Analysis and Meta-Regression.

A systematic review was undertaken to investigate the involvement of hydration in heart rate (HR), HR variability (HRV) and diastolic (DBP) and systolic (SBP) blood pressure in response to exercise. Data synthesis: The EMBASE, MEDLINE, Cochrane Library, CINAHL, LILACS and Web of Science databases were searched. In total, 977 studies were recognized, but only 36 were included after final screening (33 studies in meta-analysis). This study includes randomized controlled trials (RCTs) and non-RCTs with subjects > 18 years old. The hydration group consumed water or isotonic drinks, while the control group did not ingest liquids. For the hydration protocol (before, during and after exercise), the HR values during the exercise were lower compared to the controls (-6.20 bpm, 95%CI: -8.69; -3.71). In the subgroup analysis, "water ingested before and during exercise" showed lower increases in HR during exercise (-6.20, 95%CI: 11.70 to -0.71), as did "water was ingested only during exercise" (-6.12, 95%CI: -9.35 to -2.89). Water intake during exercise only revealed a trend of avoiding greater increases in HR during exercise (-4,60, 95%CI: -9.41 to 0.22), although these values were not significantly different (p = 0.06) from those of the control. "Isotonic intake during exercise" showed lower HRs than the control (-7.23 bpm, 95% CI: -11.68 to -2.79). The HRV values following the exercise were higher in the hydration protocol (SMD = 0.48, 95%CI: 0.30 to 0.67). The values of the SBP were higher than those of the controls (2.25 mmHg, 95%CI: 0.08 to 4.42). Conclusions: Hydration-attenuated exercise-induced increases in HR during exercise, improved autonomic recovery via the acceleration of cardiac vagal modulation in response to exercise and caused a modest increase in SBP values, but did not exert effects on DBP following exercise.

Impact of a dual glucose-dependent insulinotropic peptide/glucagon-like peptide-1 receptor agonist tirzepatide on heart rate among patients with type 2 diabetes: A systematic review and pairwise and network meta-analysis.

To evaluate the impact of a dual glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist tirzepatide (TZP), and its potential dose-response effect, on heart rate. Articles were searched from PubMed, Web of Science, Embase, Cochrane Library, and clinical trials registries (ClinicalTrials.gov) databases. Randomized controlled trials (RCTs) comparing TZP at doses of 5, 10 and 15 mg in adults with type 2 diabetes were included. Six study arms were summarized from original research (TZP 5, 10 and 15 mg, GLP-1 receptor agonists [GLP-1RAs], insulin, placebo). The GLP-1RA and non-GLP-1RA groups were combined to form a control group. Two reviewers independently extracted data and assessed the quality of each study. Mean differences (MDs) were calculated as effect estimates for continuous outcomes. Pairwise meta-analyses and network meta-analyses were conducted. The study protocol was prospectively registered (PROSPERO ID: CRD42023418551). Eight articles were included in this systematic review and meta-analysis. The mean baseline heart rate ranged from 65.2 to 75.7 beats per minute. Pairwise meta-analysis showed that, compared with combined the control group, there were significantly greater increases in heart rates in the TZP group (MD 1.82, 95% confidence interval [CI] 0.75, 2.89). Similar significant rises were identified when comparing TZP with GLP-1RAs and non-GLP-1RAs (GLP-1 RAs: MD 2.29, 95% CI 1.00, 3.59; non-GLP-1RAs: MD 1.58, 95% CI 0.26, 2.91). TZP 5 mg was associated with smaller increases in heart rates compared to TZP 10 mg and TZP 15 mg (TZP 10 mg: MD -0.97, 95% CI -1.79, -0.14; TZP 15 mg: MD -2.57, 95% CI -3.79, -1.35). TZP 10 mg increased heart rate less than TZP 15 mg (MD -1.5, 95% CI -2.38, -0.82). Network meta-analysis indicated that TZP 15 mg was associated with significant increases in heart rate compared with TZP 5 mg (MD 2.53, 95% CI 1.43, 3.62), TZP 10 mg (MD 1.44, 95% CI 0.35, 2.53), GLP-1RAs (MD 3.46, 95% CI 1.67, 5.25), insulin (MD 2.86, 95% CI 1.32, 4.41) and placebo (MD 2.96, 95% CI 1.36, 4.57). Our study showed not only that there was a greater increase in heart rate in the TZP group than in the control, GLP-1RA and non-GLP-1RA groups, but also that the 15-mg dose of TZP had the strongest impact on increasing heart rates compared with the other five inventions, with a TZP dose-response impact on heart rate. Further research on the effects of TZP treatment-related increases in heart rate is required.

Neuro-Cardiovascular Responses to Sympathetic Stimulation in Fighter Pilots.

INTRODUCTION: The chronic effects of regular exposure to high acceleration levels (G-force) on the neuro-cardiovascular system are unclear. We compared the mean arterial pressure (MAP) and cardiac autonomic modulation between nonpilots (NP) vs. military fighter (FP) and transport (TP) pilots. Additionally, we correlated the cardiac autonomic indices with the cardiorespiratory fitness and flight experience of FP.METHODS: A total of 21 FP, 8 TP, and 20 NP performed a tilt test (TT), during which beat-to-beat blood pressure and heart rate were recorded.RESULTS: No difference was detected between groups for changes in MAP and heart rate variability indices during the TT. However, the analysis of areas under the curves showed a greater increase in MAP in FP vs. TP and NP. Conversely, there was a greater decrease in indices reflecting vagal modulation in TP vs. FP and NP (rMSSD, pNN50, and SDNN), and a greater increase in heart rate and sympathovagal balance in TP vs. other groups (LF/HF). The maximal oxygen uptake was strongly correlated with the vagal reserve in FP (r = -0.74). Moreover, the total flying hours of FP were positively correlated with resting HFnu (r = 0.47) and inversely correlated with resting LFnu (r = -0.55) and LF/HF (r = -0.46).CONCLUSION: FP had a higher pressor response to TT than TP and NP. Vagal withdrawal and sympathovagal increase induced by TT in FP were similar vs. NP and attenuated vs. TP. Greater cardiorespiratory fitness and accumulated flying hours in FP seemed to favor lower sympathetic and greater vagal modulation at rest.dos Santos Rangel MV, de Sá GB, Farinatti P, Borges JP. Neuro-cardiovascular responses to sympathetic stimulation in fighter pilots. Aerosp Med Hum Perform. 2023; 94(10):761-769.

The effects of type of recovery in resistance exercise on responses of platelet indices and hemodynamic variables.

To examine the effects of two different volume-matched resistance exercise (RE) recovery protocols (passive and active) on platelet indices and hemodynamic variables. Twelve Healthy participants (mean ± SD; 25 ± 3 yrs) completed a traditional resistance exercise (TRE) protocol that included three sets of six repetitions at 80% one repetition maximum (1RM) with two minutes passive recovery between sets, exercises and an interval resistance exercise (IRE) protocol that included three sets of six repetitions at 60%1RM followed by active recovery including six repetitions of the same exercise at 20%1RM. Blood samples for multiple platelet indices were taken before the protocols, immediately-post (IP), and after 1-hour recovery. Hemodynamic variables were measured before, IP, and every five minutes during recovery. Mean platelet volume and platelet large cell ratio P_LCR decreased from baseline to recovery. Heart rate (HR) and rate pressure product (RPP) were augmented at IP following IRE compared to TRE. HR was significantly elevated for 20 minutes after both RE protocols, and RPP recovered by five minutes. Systolic blood pressure was increased at IP compared to baseline and all recovery time points for both RE protocols. Our research demonstrated that both RE protocols, produced transient increases in platelet indices (MPV, and P_LCR) and hemodynamic variables (SBP, HR, and RPP), all of which returned to baseline within an hour. Notably, the IRE protocol elicited a greater increase in HR and RPP compared to the TRE protocol.

Evaluation of Cardiovascular Response to Isometric Handgrip Exercise in Obese Individuals.

Background The variability in hemodynamic responses to isometric handgrip exercise in people with different body mass indices (BMIs) is noteworthy due to the frequent incidence of hypertension, obesity, and related cardiovascular illnesses in India. This investigation may be necessary to anticipate and prevent excessive heart strain during static activities. Therefore, this study aimed to evaluate the impact of isometric handgrip exercise on cardiorespiratory responses in an Indian population with varying BMI levels. The objective was to compare the cardiovascular responses of obese and non-obese individuals to an isometric handgrip exercise test (heart rate, systolic blood pressure, diastolic blood pressure, rate pressure product, and mean arterial pressure). Methodology This study was conducted from April 2021 to October 2022. Measurements were obtained using a pedestal-style weighing scale with a maximum capacity of 120 kg and an accuracy of 100 g at the Department of Physiology, Indira Gandhi Institute of Medical Sciences, Patna. Sphygmomanometer was used for measuring blood pressure, and a stopwatch was used to time the duration of each prolonged isometric contraction performed by the participants using a handgrip dynamometer. Baseline measurements of heart rate, blood pressure, cardiac output, and heart rate variability were done during the final three minutes of the rest phase and once more throughout the 10-minute recovery period that followed the isometric handgrip exercise. Results The average heart rate increased during the isometric handgrip exercise in the obese group (13.02 ± 1.88 beats per minute). Systolic blood pressure increased by 16.40 ± 2.65 mmHg and 23.66 ± 3.14 mmHg in the obese group and the normal weight group, respectively. The diastolic blood pressure increased similarly in the overweight and normal weight groups, measuring 18.64 ± 3.63 mmHg and 12.14 ± 1.95 mmHg, respectively. Furthermore, the mean blood pressure increased by 20.45 ± 3.13 mmHg and 13.67 ± 1.64 mmHg, respectively, both in the normal and overweight groups. Conclusions Obese individuals had greater resting heart rates, systolic blood pressure, and diastolic blood pressure than non-obese individuals. Following an isometric handgrip workout, non-obese individuals reported greater increases in heart rate, systolic blood pressure, and diastolic blood pressure than obese individuals.

High Incidence of Autonomic Dysfunction and Postural Orthostatic Tachycardia Syndrome in Patients with Long COVID: Implications for Management and Health Care Planning

BackgroundAutonomic dysfunction, including postural orthostatic tachycardia syndrome (POTS), has been reported in individuals with post-acute sequelae of COVID-19 (PASC). However, the degree of dysautonomia in PASC has not been compared to those with POTS and healthy controls. MethodsAll participants were prospectively enrolled between August 5, 2021 and October 31, 2022. Autonomic testing included beat-to-beat hemodynamic monitoring to assess respiratory sinus arrhythmia, Valsalva ratio, and orthostatic changes during a 10-minute active standing test, as well as sudomotor assessment. The Composite Autonomic Symptom Score (COMPASS-31) was used to assess symptoms and the EuroQuol 5-Dimension survey (EQ-5D-5L) was used to assess health-related quality of life (HrQoL) measures. ResultsA total of 99 participants (n = 33 PASC, n = 33 POTS, and n = 33 healthy controls; median age 32 years, 85.9% females) were included. Compared with healthy controls, the PASC and POTS cohorts demonstrated significantly reduced respiratory sinus arrhythmia (P < .001), greater heart rate increase during 10-minute active standing test (P < .001), greater burden of autonomic dysfunction evidenced by higher COMPASS-31 scores across all subdomains (all P < .001), and poor HrQoL across all EQ-5D-5L domains (all P < .001), lower median EuroQol-visual analogue scale (P < .001), and lower utility scores (P < .001). The majority (79%) of those with PASC met the internationally established criteria for POTS. ConclusionThe prevalence of autonomic symptomology for POTS was high in those with PASC, leading to poor HrQoL and high health disutility. Autonomic testing should be routinely undertaken in those with PASC to aid diagnosis and direct appropriate management to improve health outcomes.

The effects of a single and a series of Finnish sauna sessions on the immune response and HSP-70 levels in trained and untrained men

Background The aim of the study was to investigate the effect of a Finnish sauna on the immune status parameters. The hypothesis was that hyperthermia would improve immune system’s functioning by changing the proportion of lymphocyte subpopulations and would activate heat shock proteins. We assumed that the responses of trained and untrained subjects would be different. Material and methods Healthy men (20–25 years old) were divided into groups: the trained (T; n = 10), and the untrained group (U; n = 10). All participants were subjected to 10 baths (each one consisted of: 3 × 15-minute exposure with cooled down for 2 min. Body composition, anthropometric measurements, VO2 peak were measured before 1st sauna bath. Blood was collected before the 1st and 10th sauna bath, and 10 min after their completion to asses an acute and a chronic effect. Body mass, rectal temperature and heart rate (HR) were assessed in the same time points. The serum levels of cortisol, Il-6, HSP70 were measured with use of ELISA method, IgA, IgG and IgM by turbidimetry. White blood cells (WBC), leukocyte populations counts: neutrophils, lymphocytes, eosinophils, monocytes, and basophils were determined with use of flow cytometry as well as T-cell subpopulations. Results No differences were found in the increase in rectal temperature, cortisol and immunoglobulins between groups. In response to the 1st sauna bath, a greater increase in HR was observed in the U group. After the last one, the HR value was lower in the T group. The impact of sauna baths on WBC, CD56+, CD3+, CD8+, IgA, IgG and IgM was different in trained and untrained subjects’ responses. A positive correlation between the increase in cortisol concentrations and increase in internal temperatures after the 1st sauna was found in the T (r = 0.72) and U group (r = 0.77), between the increase in IL-6 and cortisol concentrations in the T group after the 1st treatment (r = 0.64), between the increase in IL-10 concentration and internal temperature (r = 0.75) and between the increase in IL-6 and IL-10 (r = 0.69) concentrations, also. Conclusions Sauna bathing can be a way to improve the immune response, but only when it is undertaken as a series of treatments.

Respostas hemodinâmicas durante exercício muscular inspiratório em jovens saudáveis

ABSTRACT The literature on hemodynamic responses during inspiratory muscle exercise (IME) lacks a consensus. To evaluate and compare hemodynamic responses during an IME session with and without resistive load, 15 sedentary men were subjected to two randomized IME sessions: one with 40% of maximal inspiratory pressure (IME 40%) and another without a resistive load (Sham), both of which were performed for two minutes over eight sessions with one-minute intervals. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), total peripheral resistance (TPR), stroke volume (SV), cardiac output (CO), and heart rate (HR) were measured by infrared digital photoplethysmography during five basal minutes and during the IME sessions. One-way analysis of variance and the Student’s t test for paired data were used to analyze hemodynamic response and delta values between sessions. Effect size was evaluated by Cohen’s D. A 5% significance level was adopted. SBP responses (sham: ∆−1±2 vs. 40%: ∆−4±2mmHg, p=0.27), DBP (sham: ∆2±1 vs. 40%: ∆1±2mmHg, p=0.60) and MBP (sham: ∆2±1 vs. 40%: ∆0±2mmHg, p=0.28) were similar between sessions. HR increases were higher in the 40% IME session than in the sham session (sham: ∆9±2 vs. 40%: ∆3±2bpm, p=0.001). SV only decreased during the sham session but responses were similar between sessions (sham: ∆−2±2 vs. IME 40%: ∆−6±2ml, p=0.13). Both sessions did not change SBP, DBP, MBP, CO, and TPR, but we observed a greater increase in HR in the IME 40% session. Only the Sham session decreased SV.

Behavioral and physiological differences during an emotion-evoking task in children at increased likelihood for autism spectrum disorder.

Literature examining emotional regulation in infants with autism spectrum disorder (ASD) has focused on parent report. We examined behavioral and physiological responses during an emotion-evoking task designed to elicit emotional states in infants. Infants at an increased likelihood for ASD (IL; have an older sibling with ASD; 96 not classified; 29 classified with ASD at age two) and low likelihood (LL; no family history of ASD; n = 61) completed the task at 6, 12, and 18 months. The main findings were (1) the IL-ASD group displayed higher levels of negative affect during toy removal and negative tasks compared to the IL non-ASD and LL groups, respectively, (2) the IL-ASD group spent more time looking at the baseline task compared to the other two groups, and (3) the IL-ASD group showed a greater increase in heart rate from baseline during the toy removal and negative tasks compared to the LL group. These results suggest that IL children who are classified as ASD at 24 months show differences in affect, gaze, and heart rate during an emotion-evoking task, with potential implications for understanding mechanisms related to emerging ASD.

Development of pulsed intravenous nicotine infusions as a model for inhaled nicotine in humans.

Although nicotine from cigarettes is delivered in puff-sized amounts, most preclinical and human intravenous (IV) nicotine studies have used bolus or continuous infusions. To determine the feasibility of a pulsed-nicotine infusion model in smokers. Following overnight abstinence, 12 adult smokers underwent 5 laboratory sessions. Using a crossover design, in each session, participants were assigned to 1 of 5 conditions: (1) high/fast: 1.0mg nicotine delivered over 5 pulsed-infusions, then 15 saline infusions; (2) high/slow: 1.0mg nicotine delivered over 20 pulsed-infusions; (3) low/fast: 0.2mg nicotine delivered over 5 pulsed-infusions, then 15 saline infusions; (4) low/slow: 0.2mg nicotine delivered over 20 pulsed-infusions; and (5) placebo: Saline delivered over 20 pulsed-infusions. Subjective drug effects, urges to smoke, nicotine withdrawal, and cognitive performance were measured in each session. Both the high/fast and high/slow conditions were associated with greater "head rush" and "high" (p < 0.05). The high/fast condition also provided greater suppression of urges to smoke and nicotine withdrawal (p < 0.05), indexed by the Questionnaire of Urges to Smoke-Brief, and the Minnesota Nicotine Withdrawal Scale, respectively. The high/fast and high/slow conditions produced greater increases in heart rate (p < 0.01) than saline. Finally, there were no main effects of dosing conditions on cognitive performance, indexed by the continuous performance test. These findings demonstrate the feasibility of pulsed-nicotine infusions to model nicotine delivery by smoking. This model could inform future studies testing novel smoking cessation therapies and tobacco regulatory studies testing the impact of nicotine reduction approaches.

Effects of sex and wet-bulb globe temperature on heart rate variability during prolonged moderate-intensity exercise: a secondary analysis.

Sex differences in heart rate (HR) and heart rate variability (HRV), a surrogate of cardiac autonomic modulation, are evident during rest and exercise in young healthy individuals. However, it remains unclear whether sex impacts HRV during prolonged exercise at differing levels of environmental heat stress. Therefore, we completed a secondary analysis upon the effects of sex and wet-bulb globe temperature (WBGT) on HR and HRV during prolonged exercise. To achieve this, HR and HRV were assessed in non-endurance-trained and non-heat-acclimatised healthy men (n=19) and women (n=15) aged 18-45 years during 180min of treadmill walking at a moderate metabolic rate (200W/m2: equivalent to ∼35% peak aerobic power) in 16, 24, 28, and 32°C WBGT. In the final 5min prior to exercise termination, HR was observed to be higher in women relative to men in all but the 32 °C WBGT. Although no sex differences were observed for the HRV metric of root-mean-square of successive differences, high-frequency power was higher in women relative to men across WBGT conditions. These findings indicate that, in healthy non-heat-acclimatised individuals, women respond to prolonged exercise-heat stress with a greater increase in HR despite cardiac vagal autonomic modulation remaining equal or increasing compared to men. Novelty: Prior to exercise termination, females respond with a greater increase in HR under all WBGTs except the hottest (32 °C). Sexinfluenced HRV metrics during all WBGTs, but results were mixed. Further characterisation of HRV sex differences remains an important area of research.

Effects of Preoperative Anxiety Status on Haemodynamic Changes during and after Tooth Extraction in Middle-aged and Elderly Patients with Hypertension: a Prospective Repeated-Measures Cohort Study.

To investigate the effects of dental anxiety on fluctuations in blood pressure (BP) and heart rate (HR) during tooth extraction in hypertensive patients under local anaesthesia, and how they are influenced by various confounding variables. This is a prospective repeated-measures cohort study involving 600 patients successively recruited from Peking University School and Hospital of Stomatology, Beijing, China. BP and HR were repeatedly measured at rest (T0), before anaesthesia (T1), during tooth extraction (T2) and after tooth extraction (T3). Anxiety status was measured prior to local anaesthesia using a modified dental anxiety scale (MDAS). Three groups were assigned: mild anxiety (Corah DAS score of 4 to 8), moderate anxiety (score of 9 to 12) and severe anxiety (score of 13 to 20). We used a generalised linear mixed model (GLMM) to analyse the effects of dental anxiety on fluctuations in BP and HR. Interaction analysis was used to further explore the correlationship between these interactive factors. The mean anxiety scale score was 9.63 ± 2.88. Severe preoperative anxiety (score of 14 to 20) was associated with significantly increased HR during administration of anaesthesia. Patients with severe anxiety also displayed a significantly greater increase in HR during anaesthetic administration (P < 0.001). When analysing the joint effects of different anxiety statuses over time, blood pressure was significantly elevated in all patients with moderate and severe anxiety during tooth extraction at T2 (β = 1.25, 95% CI 0.24 to 2.27). We also observed a significant decrease in HR in the moderate anxiety group at T3 (β = -1.51, 95% CI -2.38 to -0.63) and a significant increase in HR in the severe anxiety group at T1, T2 and T3 (β = 2.52, 95% CI 1.12 to 3.93; β = 3.84, 95% CI 2.30 to 5.38; β = 4.57, 95% CI 3.03 to 6.11, respectively). This study indicates that the effects of dental anxiety on BP and HR in middle-aged and elderly patients with hypertension during local anaesthesia and tooth extraction were influenced by various confounding variables.

Muscle Oxygenation, Neural, and Cardiovascular Responses to Isometric and Workload-matched Dynamic Resistance Exercise.

Differences in blood flow patterns and energy cost between isometric and dynamic resistance exercise may result to variant cardiovascular, neural, and muscle metabolic responses. We aimed to compare the cardiovascular, baroreceptor sensitivity, and muscle oxygenation responses between workload-matched, large muscle-mass isometric and dynamic resistance exercises. Twenty-four young men performed an isometric and a dynamic double leg-press protocol (4 sets×2 min) with similar tension time index (workload). Beat-by-beat hemodynamics, baroreceptor sensitivity, muscle oxygenation, and blood lactate were assessed. The increase in blood pressure was greater (p<0.05) in the 1st set during dynamic than isometric exercise (by ~4.5 mmHg), not different in the 2nd and 3rd sets, and greater in the 4th set during isometric exercise (by ~5 mmHg). Dynamic resistance exercise evoked a greater increase in heart rate, stroke volume, cardiac output, and contractility index (p<0.05), and a greater decline in peripheral resistance, baroreceptor sensitivity, and cardiac function indices than isometric exercise (p<0.05). Participants exhibited a greater reduction in muscle oxyhemoglobin and a greater increase in muscle deoxyhemoglobin in dynamic versus isometric exercise (p<0.001-0.05), with no differences in total hemoglobin and blood lactate. In conclusion, large muscle-mass, multiple-set isometric exercise elicits a relatively similar blood pressure but blunted cardiovascular and baroreceptor sensitivity responses compared to workload-matched dynamic resistance exercise. Differences in blood pressure responses between protocols appear small (~5 mmHg) and are affected by the number of sets. The muscle oxidative stimulus is greater during dynamic resistance exercise than workload-matched isometric exercise.

Cardiovascular and cortisol responses to experimentally-induced minority stress.

Lesbian, gay, and bisexual (LGB) individuals who report greater minority stress (e.g., discrimination) are at an elevated risk for multiple health problems. However, few studies have examined physiological mechanisms that might link minority stress to health. This study tested how cardiovascular and cortisol responses to a laboratory-induced social stressor differed when that stressor contained an additional minority stress component. LGB adults (n = 141; 51% male, 49% female) participated in a social stress task in which they were interviewed by a prerecorded confederate. Participants were randomized to receive information that their interviewer held either antigay or progay social/political beliefs. Cardiovascular reactivity and salivary cortisol were assessed at baseline, during the task, and during recovery. All participants experienced significant task-related increases in heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP). However, participants in the antigay condition had greater increases in HR and SBP during the task and smaller decreases in SBP during recovery. Salivary cortisol increased significantly only in the antigay condition. High frequency heart rate variability (hfHRV) was constant throughout the stress task for participants in the progay condition but decreased significantly during the task for participants in the antigay condition. Minority stress has the potential to affect LGB individuals' health through cardiovascular and endocrine mechanisms. Moreover, its physiological signature may differ from other social stress in ways that have implications for health and emotion regulation more broadly. (PsycInfo Database Record (c) 2021 APA, all rights reserved).