Lower Resting Heart Rate Research Articles

Elevated resting heart rates are a risk factor for mortality among patients with coronavirus disease 2019 in Wuhan, China.

ABSTRACTBackground:We evaluated the association between higher resting heart rates (RHRs) and adverse events in COVID-19 patients.Methods:One hundred and thirty-six patients with laboratory-confirmed COVID-19 were admitted. Outcomes of patients with different RHRs were compared.Results:Twenty-nine patients had RHRs of <80 bpm (beat per min), 85 had 80–99 bpm and 22 had ≥100 bpm as tachycardia. Those with higher RHRs had lower pulse oxygen saturation (SpO2) and higher temperatures, and there was a higher proportion of men upon admission (all P < 0.05). Patients with higher RHRs showed higher white blood cell counts and D-dimer, cardiac troponin I (TnI), N-terminal pro-B-type natriuretic peptide and hypersensitive C-reactive protein levels, but lower albumin levels (all P < 0.05) after admission. During follow-up, 26 patients died (mortality rate, 19.1%). The mortality rate was significantly higher among patients with tachycardia than among the moderate and low RHR groups (all P < 0.001). Kaplan–Meier survival curves showed that the risks of death and ventilation use increased for patients with tachycardia (P < 0.001). Elevated RHR as a continuous variable and a mean RHR as tachycardia were independent risk factors for mortality and ventilator use (all P < 0.05) in the multivariable adjusted Cox proportional hazards regression model.Conclusions:Elevated average RHRs during the first 3 days of hospitalisation were associated with adverse outcomes in COVID-19 patients. Average RHRs as tachycardia can independently predict all-cause mortality.

The effects of cannabis use on physical health: A co-twin control study

BackgroundResearch on the influence of cannabis use on anthropometrics, cardiovascular and pulmonary function, and other indicators of physical health has reported mixed results. We examined whether cannabis frequency is associated with physical health outcomes phenotypically and after controlling for shared genetic and environmental factors via a longitudinal co-twin control design. MethodsWe tested the phenotypic associations of adolescent, young adult, and adult cannabis frequency with adult physical health. Next, we ran multilevel models to test if significant phenotypic associations remained at the between-family and within-twin pair levels. Participants include 677 individual twins (308 twin pairs) aged 25–35. ResultsAt the phenotypic level, adolescent cannabis use was associated with less adult exercise engagement (b = − 0.846 min, p = .000). Adult cannabis use was associated with a lower resting heart rate (HR; b = − 0.170 bpm, p = .001) and more frequent appetite loss (b = 0.018, p = .000). Only between-family effects were significant for adolescent cannabis use and exercise engagement (b = − 1.147 min, p = .000) and adult cannabis use and appetite loss frequency (b = 0.041, p = .002). The total within-twin (b = − 0.184, p = .014), MZ only (b = − 0.304, p = .003), and between-family effects (b = − 0.164, p = .025) were significant between adult cannabis use and a lower resting HR, which persisted after controlling for familial confounds and other substance use. ConclusionsThe associations between cannabis use with exercise engagement and frequency of appetite loss are explained by familial confounding while the association between cannabis use and resting HR was not. These results do not support a causal association between cannabis use once a week and poorer physical health effects among adults aged 25–35.

Long-term impact of β-blocker in elderly patients without myocardial infarction after percutaneous coronary intervention.

AimsLittle is known about the long‐term outcomes of β‐blockers use in patients with coronary artery disease (CAD) without myocardial infarction (MI) and reduced ejection fraction (rEF). However, more attention should be paid to the oral administration of β‐blockers in elderly patients who are susceptible to heart failure (HF), sinus node dysfunction, or rate response insufficiency. We aimed to evaluate the long‐term impact of β‐blockers in elderly patients with CAD without MI or systolic HF who have undergone percutaneous coronary intervention.Methods and resultsA total of 1018 consecutive elderly patients with CAD (mean age, 72 ± 7 years; 77% men) who underwent their first intervention between 2010 and 2018 were included in this study. According to the presence or absence of the use of β‐blockers, 514 patients (50.5%) were allocated to the β‐blocker group, and 504 (49.5%) to the non‐β‐blocker group. We evaluated the incidence of 4‐point major adverse cardiovascular events (4P‐MACE), including cardiovascular death, non‐fatal MI, non‐fatal stroke, admission for HF, target vessel revascularization (TVR), and all‐cause death. We focused on the association between chronotropic incompetence of β‐blockers and incidence of a new HF and analysed the results using an exercise electrocardiogram regularly performed in the outpatient department after percutaneous coronary intervention. During a median follow‐up duration of 5.1 years, 83 patients (8.3%) developed 4P‐MACE, including cardiovascular death in 17, non‐fatal MI in 13, non‐fatal stroke in 25, and admission for HF in 39 patients. Additionally, 124 patients (12.2%) had a TVR and 104 (10.2%) died of other causes. Kaplan–Meier analysis showed that the cumulative incidence rate of 4P‐MACE in the β‐blocker group was significantly higher than that in the non‐β‐blocker group (15.4% vs. 10.0%, log‐rank test, P = 0.015). Above all, the cumulative incidence rate of admission for HF in the β‐blocker group was significantly higher (8.8% vs. 3.2%, log‐rank test, P < 0.001). The β‐blocker group had significantly lower resting heart rate, stress heart rate, and stress‐rest Δ heart rate on exercise electrocardiogram. Multivariate Cox hazard analysis revealed that EF, β‐blocker use, stress‐rest Δ heart rate, and CKD were strong independent predictors of admission for HF.ConclusionsLong‐term β‐blocker use was significantly associated with an increased risk of adverse cardiovascular events in elderly patients with CAD without MI or systolic HF. In particular, the chronotropic incompetence action of β‐blockers could increase the risk of admission for HF in elderly patients with CAD without MI and systolic HF, and the present findings warrant further investigation.

Increased resting heart rate and glucose metabolism in a community population

ObjectiveResting heart rate (RHR) independently predicts cardiovascular death. Increased RHR is related to chronic diseases, but community-based studies are rare. We investigated this population and factors related to RHR.MethodsIn total, 374 participants underwent medical examinations from March 2019 to December 2019. Participants were divided into groups with low RHR (LRHR; <65 beats/minute) and high RHR (HRHR; ≥65 beats/minute). RHR was judged using resting electrocardiogram at physical examination. We conducted laboratory examinations, including glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), and blood lipids, among participants with chronic diseases. We used Cox proportional risk regression and multivariate analyses for the following covariates: previous chronic diseases, body mass index (BMI), smoking, blood lipids, and FPG.ResultsThe incidence of type 2 diabetes mellitus (T2DM) and HbA1c values were both significantly higher in the HRHR group than in the LRHR group. Spearman correlation analysis showed RHR had a positive correlation with low-density lipoprotein, BMI, FPG, and HbA1c (r = 0.104574, 0.117266, 0.116041, and 0.311761, respectively). Multiple linear regression analysis showed age, hypertension, T2DM, and HbA1c were factors influencing RHR.ConclusionRHR showed strong correlation with T2DM and HbA1c in our community population, suggesting that RHR may be a risk factor for cardiovascular disease.

A Rare Skin Disorder with Bacteremia in a Neonate.

A Rare Skin Disorder with Bacteremia in a Neonate.

A-37 Interactions between in-Utero Stress Exposure, Externalizing Behavior, and Psychophysiology in Young Children

Abstract Objective The current study examines the associations between low resting heart rate (HR), low electrodermal activity (EDA), and externalizing behavior (EB) in children 1–5 years old through the following measures: baseline 1 (B1) HR, startle period HR, and recovery-stage HR HR, EDA amplitude and skin conductance responses (SCR). We also investigate whether in-utero stress (exposure to Hurricane Sandy) moderates these relationships. Method A subsample of 206 children was drawn from a NIMH longitudinal study, the Stress in Pregnancy Study, that follows offspring from in-utero to 6 years of age. HR and EDA data was collected during a startle-probe paradigm. Mean age of the participants was 3.89 years. Approximately 52% were female and 50.5% were Hispanic. Participants’ EB was assessed by the Behavioral Assessment Screening for Children Version-2 parent rating scales. Externalizing symptoms were trichotomized (high, medium, and low). Results One-way ANOVA showed that three EB groups differed in baseline-HR (p = 0.034), startle-HR (p = 0.006), and recovery-stage HR (p = 0.008) in 4-year olds. EDA was not significantly different between EB groups. Furthermore, Hurricane Sandy exposure significantly and marginally significantly moderates the relationship between EB and amplitude (b = 3.0344, p = 0.044) and EB and SCR (b = 1.5629, p = 0.056), respectively. Hurricane Sandy exposure did not moderate the relationship between EB and HR. Conclusion Externalizing problem symptom groups significantly differ in HR, but not EDA. Hurricane Sandy exposure moderates the relationship between EB and EDA, but not EB and HR. Results suggest that HR and EDA are differentially susceptible to environmental influence. Results can guide biologically informed treatments/screeners for EB in children.

Low autonomic arousal as a risk factor for reoffending: A population-based study.

BackgroundLow resting heart rate (RHR) and low systolic blood pressure (SBP) are associated with criminal behavior. However, knowledge is lacking about their predictive value for reoffending.AimWe aimed to examine associations of RHR and SBP with reoffending in a large population-based sample.MethodsWe conducted a cohort study of all convicted male conscripts born in Sweden 1958–1990 (N = 407,533). We obtained data by linking Swedish population-based registers. Predictor variables were RHR and SBP, measured at conscription which was mandatory until 2010 for men at age 18. The outcome variable was reoffending, defined as criminal convictions (any crime, violent crime and non-violent crime), obtained from the National Crime Register. We used survival analyses to test for associations of RHR and SBP with reoffending, adjusting for pertinent covariates such as socioeconomic status, height, weight and physical energy capacity.ResultsIn fully adjusted Cox regression models, men with lower RHR (≤60 bpm) had higher risk of reoffending (any crime: HR = 1.17, 95% CI: 1.14, 1.19, violent crime: HR = 1.23, 95% CI: 1.17, 1.29, non-violent crime: HR = 1.16, 95% CI: 1.14, 1.19), compared to men with higher RHR (≥ 82 bpm). Men with lower SBP (≤80 mmHg) had higher risk of reoffending (any crime: HR = 1.19, 95% CI: 1.17, 1.21, violent crime: HR = 1.16, 95% CI: 1.12, 1.20, non-violent crime: HR = 1.20, 95% CI: 1.18, 1.22), compared to men with higher SBP (≥138 mmHg).ConclusionsLow autonomic arousal is associated with increased risk of reoffending. RHR and SBP should be investigated further as potential predictors for reoffending as they each may have predictive value in risk assessment protocols.

Frequency of Heterozygous Parkin (PRKN) Variants and Penetrance of Parkinson's Disease Risk Markers in the Population-Based CHRIS Cohort.

Mutations in the Parkin (PRKN) gene are the most frequent cause of autosomal recessive early-onset Parkinson's disease (PD). Heterozygous PRKN mutation carriers might also be at increased risk for developing clinical symptoms of PD. Given the high frequency of heterozygous mutations in the general population, it is essential to have better estimates of the penetrance of these variants, and to investigate, which clinical and biochemical markers are present in carriers and thus potentially useful for identifying those individuals at greater risk of developing clinical symptoms later in life. In the present study, we ascertained the frequency of heterozygous PRKN mutation carriers in a large population sample of the Cooperative Health Research in South Tyrol (CHRIS) study, and screened for reported PD risk markers. 164 confirmed heterozygous PRKN mutation carriers were compared with 2,582 controls. A higher number of heterozygous mutation carriers reported a detectable increase in an akinesia-related phenotype, and a higher percentage of carriers had manifested diabetes. We also observed lower resting heart rate in the PRKN mutation carriers. Extending our risk analyses to a larger number of potential carriers and non-carriers using genotype imputation (n = 299 carriers and n = 7,127 non-carriers), from previously published biomarkers we also observed a higher neutrophil-to-lymphocyte ratio (NLR) and lower serum albumin and sodium levels in the heterozygous PRKN variant carriers. These results identify a set of biomarkers that might be useful either individually or as an ensemble to identify variant carriers at greater risk of health issues due to carrier status.

Resting Heart Rate and Cardiovascular Outcomes during Intensive and Standard Blood Pressure Reduction: An Analysis from SPRINT Trial.

The association between elevated resting heart rate (RHR) as a cardiovascular risk factor and lowering of systolic blood pressure (SBP) to currently recommended values remain unknown. Systolic Blood Pressure Intervention Trial (SPRINT) data obtained from the NHLBI were used to describe the relationship between RHR and SBP reduction to <120 mmHg compared to SBP reduction to <140 mmHg. The composite clinical endpoint (CE) was defined as myocardial infarction, acute coronary syndrome, decompensation of heart failure, stroke, or cardiovascular death. Increased RHR was associated with a higher CE risk compared with low RHR in both treatment arms. A more potent increase of risk for CE was observed in subjects who were allocated to the SBP < 120 mmHg treatment goal. A similar effect of intensive and standard blood pressure (BP) reduction (p for interaction, 0.826) was observed in subjects with RHR in the 5th quintile (hazard ratio, 0.78, with 95% confidence interval (CI), 0.55–1.11) and in other quintiles of baseline RHR (hazard ratio, 0.75, with 95% CI, 0.62–0.90). Lower in-trial than baseline RHR was associated with reduced CE risk (hazard ratio, 0.80, with 95% CI, 0.66–0.98). We concluded that elevated RHR remains an essential risk factor independent of SBP reduction.

Resting heart rate is associated with colorectal advanced adenoma.

Background and aimsResting heart rate is an independent predictor of colorectal cancer (CRC) development and CRC-related mortality. However, little is known about the relationship between resting heart rate and colorectal adenoma development. We aimed to investigate this association in a population who underwent screening colonoscopy.MethodsAmong 39,021 patients who underwent both electrocardiogram and screening colonoscopy during routine health examinations at the Seoul National University Bundang Hospital, Health Promotion Center, Korea from January 2014 to July 2019, 1,344 patients had advanced adenoma. We performed 1:1 propensity score (PS) matching to establish a control group that mitigated the confounding effects of age and sex. We performed multivariate logistic regression analyses to identify the independent risk factors of advanced adenoma development.ResultsResting heart rate was significantly higher in the advanced adenoma group than in the control group. The prevalence of advanced polyp increased across the quartiles of resting heart rate. Patients with higher resting heart rates were more likely to be older, smokers, and have increased blood pressure and DM and less likely to engage in active exercises than those with lower resting heart rates. Patients with higher resting heart rates had higher serum glucose, triglyceride, hemoglobin A1C, and insulin levels and lower high-density lipoprotein cholesterol levels. Patients with resting heart rate in the highest quartile (≥71 bpm) still showed significantly increased odds ratio (OR) of advanced adenoma development (OR: 1.379, 95% confidence interval: 1.099–1.731, p = 0.006).ConclusionsHigh resting heart rate was a meaningful independent risk factor of advanced adenoma development.

Resting Heart Rate Mediates the Relationship between Parenting Style and Callous-Unemotional Traits in Chinese Children.

Despite increasing knowledge of social and biological risk factors for callous-unemotional (CU) traits, relatively less is known about how these two sets of risk factors combine to affect these traits. The current longitudinal study investigated pathways from parenting style to CU traits via resting heart rate in a three-year project. Parents of 382 children completed the Parenting Styles and Dimensions Questionnaire at Time 1 (children Mean age = 9.06, SD = 0.94, range = 7-11years), with the heart rate data collected at Time 2 (M = 10.16, SD = 0.93, range = 8-13years) and CU traits assessed at Time 3 (M = 11.06, SD = 0.94, range = 9-13years). We found that parenting style and CU traits were associated with resting heart rate, and that structural equation modeling showed resting heart rate to partially mediate the effect of parenting style on CU traits. Specifically, higher levels of authoritarian parenting were associated with lower resting heart rate, which in turn was linked to higher level of CU traits. On the contrary, children in the context of authoritative parenting showed relatively higher resting heart rate, which was predictive of lower CU traits. Overall, findings have implications for understanding the etiology of CU traits in children and developing effective prevention programs for children with affective deficits.

Strain echocardiography to describe left ventricular function pre- and postexercise in elite basketball athletes: A feasibility study.

Elite athletes show structural cardiac changes as an adaptation to exercise. Studies examining strain in athletes have largely analyzed images at rest only. There is little data available regarding the change in strain with exercise. Our objectives were: to investigate the feasibility of strain analysis in athletes at peak exercise, to determine the normal range of left ventricular (LV) global longitudinal strain (GLS) within this population postexercise, to describe how LV GLS changes with exercise, and to determine whether any clinical characteristics correlate with the change in GLS that occurs with exercise. We conducted a cross-sectional study on elite athletes who participated in the 2016-2018 National Basketball Association Draft Combines. Echocardiograms were obtained at rest and after completing a treadmill stress test to maximal exertion or completion of Bruce protocol. Primary outcomes included GLS obtained at rest and peak exercise. Secondary outcome was the change in GLS between rest and exercise. Univariate relationships between various clinical characteristics and our secondary outcome were analyzed. Our final cohort (n=111) was all male and 92/111 (82.9%) were African American. Mean GLS magnitude increased in response to exercise (-17.6±1.8 vs -19.2±2.6, P<.0001). Lower resting heart rates (r=.22, P=.02) and lower heart rates at peak exercise (r=.21, P=.03) correlated with the increase in LV GLS from exercise. Strain imaging is technically feasible to obtain among elite basketball athletes at peak exercise. Normative strain response to exercise from this study may help identify abnormal responses to exercise in athletes.

High resting heart rate protects against childhood risk factors in predicting adult psychopathy

PurposePrevious research has indicated that low resting heart rate (RHR), measured at age 18, predicts later psychopathy, and that high RHR acts as a protective factor in nullifying the influence of several psychosocial risk factors in predicting later antisocial and criminal outcomes. This paper aims to investigate high RHR as a protective factor against age 8–10 psychosocial risk factors in predicting psychopathy factors at age 48 (measured by the PCL:SV).Design/methodology/approachData collected in the Cambridge Study in Delinquent Development are analyzed. This is a prospective longitudinal study of 411 London males from age 8 to age 61.FindingsThis paper first reports the age 8–10 psychosocial risk factors that predict the interpersonal/affective Factor 1 and the lifestyle/antisocial Factor 2. Then interaction effects with high RHR are studied. The results indicate that high RHR acts as a protective factor against a convicted father and a depressed mother in predicting both psychopathy factors. It also protected against harsh discipline, large family size, low verbal IQ, high hyperactivity, poor parental supervision and a high delinquency-rate school in predicting one of these psychopathy factors, and against a convicted mother in a sensitivity analysis.Originality/valueThis is the first ever longitudinal study showing that high RHR acts as a protective factor in the prediction of psychopathy. The replicated results with different antisocial outcomes show that more research is warranted on the protective effects of high RHR.

INFLUENCE OF RESTING HEART RATE ON BLOOD PRESSURE LOWERING EFFECT

Objective: Elevated resting heart rate (RHR) identifies hypertensive subjects at higher cardiovascular risk. The study was aimed to compare benefit of intensive blood pressure (BP) lowering in subjects with higher and lower RHR. Design and method: The analysis was performed using Systolic Blood Pressure Intervention Trial (SPRINT) data shared by National Heart, Lung and Blood Institute. SPRINT trial assessed intensive lowering of systolic BP to a target &lt; 120 mm Hg in comparison to standard goal (&lt; 140 mm Hg). Baseline RHR was estimated as a pulse rate obtained during automated office BP measurements at first study visit. RHR higher than 80 b.p.m. was defined as increased according to current European Society of Cardiology guidelines. Composite outcome event (CE) included myocardial infarction and other acute coronary syndrome, stroke, heart failure decompensation and cardiovascular death. Cox proportional model was used to assess impact of BP lowering in subjects with RHR higher and lower than 80 bpm. P-value for interaction between study BP intervention and baseline RHR. Results: Data of 9361 SPRINT participants, aged 67.9 ± 9.4 years, were analyzed. 3332 (35.6%) were female an 1877 (20.1%) were diagnosed with prior cardiovascular disease. Mean baseline RHR was 66.3 ± 11.6 b.p.m. Baseline HR in both treatment arms was similar (standard arm 66.3 ± 11.7 b.p.m. vs intensive arm 66.2 ± 11.5 b.p.m., p = 0.762) 1198 (12.8%) participants had baseline RHR higher than 80 b.p.m. and experienced 78 (6.8%) CE events. There were 484 (5.9%) events among subjects with RHR lower than 80 b.p.m. Intensive lowering of systolic BP was beneficial both in subjects with elevated RHR (hazard ratio 0.79 with 95% confidence interval 0.51–1.24, p = 0.311) and non-elevated RHR (hazard ratio 0.75 with 95% CI 0.62–0.89, p = 0.002). The intervention between study BP intervention and baseline RHR was not significant (p for interaction 0.819). Conclusions: Elevated RHR does not influence effect of BP reduction on cardiovascular events risk.

Resting Heart Rate as a Predictor of Cancer Mortality: A Systematic Review and Meta-Analysis.

This work was aimed to synthetize the evidence available about the relationship between resting heart rate (RHR) and the risk of cancer mortality. A computerized search in the Medline, EMBASE, Web of Science, and Cochrane Library databases from their inception to 24 September 2020 was performed. We performed three meta-analyses: (1) cancer mortality comparing the “less than 60 bpm” and “more than 60 bpm” categories; (2) cancer mortality comparing “less than 60 bpm”, “60 to 80 bpm”, and “more than 80 bpm” categories; and (3) analysis for 10–12 and 20 bpm increase in RHR and risk of cancer mortality. Twenty-two studies were included in the qualitative review, and twelve of them met the inclusion criteria for the meta-analysis. Our results showed a positive association between RHR and the risk of cancer mortality. This association was shown in a meta-analysis comparing studies reporting mean RHR values below and above 60 bpm, when comparing three RHR categories using less than 60 bpm as the reference category and, finally, in dose response analyses estimating the effect of an increase of 10–12 bpm in RHR, both in men and in women. In conclusion, a low RHR is a potential marker of low risk of cancer mortality.

Blood lead and mercury levels are associated with low resting heart rate in community adolescent boys.

While the neurotoxic effects of heavy metals at even low levels have been well-studied, few studies have examined the cardiovascular effects of heavy metals on resting heart rate and these have focused on adult populations. The present study aimed to examine the association between low-level environmental lead and mercury exposure and resting heart rate in community adolescents. As part of the China Jintan Cohort Study, 532 adolescents aged 12 years (SD=0.6) were tested for blood levels of lead (BLL) and mercury (BML) and resting heart rate (RHR). Generalized linear models were conducted to test the relationship between BLL and BML and RHR, controlling for children's sex, age, and socioeconomic status. Analyses were clustered at the preschool level when the children were recruited to adjust for standard error. The mean (SD) BLL and BML were 3.14 (SD=1.19) μg/dL and 1.26 (SD=0.68) μg/L at age 12 years, respectively. After adjusting for confounders, we found a significant interaction between BML and BLL in predicting RHR in boys (B=-1.27, SE=0.49, p<0.01, n=289). We created BLL and BML groups in boys based on median cut-offs. Boys in the High BLL/High BML group had significantly lower RHR (mean=84.22 beats per minute [bpm], SD=8.77, n=61) than boys in the Low BLL/Low BML group (mean=89.03 bpm, SD=10.75, n=69; p<0.05). BML and BLL did not interact to predict RHR in girls (B=-0.18, SE=0.88, p>0.05, n=242). Combined high BLL and BML were associated with low RHR in community adolescent boys. Low RHR is an indication of chronic under-arousal and has been implicated in psychopathology, particularly for externalizing behavior. Our findings may stimulate further communication and research in this area.

Psychometrics, interpretation and clinical implications of hierarchical models of psychopathology.

Psychometrics, interpretation and clinical implications of hierarchical models of psychopathology.

Heart Rate Variability and Erectile Function in Younger Men: A Pilot Study.

Erectile dysfunction (ED) in younger men is an increasing concern. In middle aged and older men, ED was related to lower resting heart rate variability (HRV), but research in younger men is lacking. The present study examined, in a nonclinical sample of 105 men between 18 and 39years, the association of ED with several parameters of resting HRV. Scores of the 5-item version of the International Index of Erectile Function (IIEF-5) below 22 were considered as indicating ED. Eighteen men (17.1%) reported ED (mild in 16, mild to moderate in 2). Welch's tests revealed that ED was associated with lower low-frequency power (LF), lower high-frequency power (HF), lower standard deviation of interbeat intervals, and lower standard deviation of the heart rate, which is influenced by both sympathetic and parasympathetic activity. After removing outliers, ED was unrelated to HF. In younger men, erections might be facilitated by a combination of higher parasympathetic tone and relatively higher sympathetic tone in the heart, as indicated by LF and greater standard deviation of the heart rate, a largely overlooked parameter in HRV research.

Association of muscle fiber composition with health and exercise-related traits in athletes and untrained subjects.

Skeletal muscle is a heterogenous and metabolically active tissue, the composition of which is associated with multiple traits. The aim of the study was to determine whether there are additional health and exercise-related traits associated with muscle fiber composition in athletes and non-athletes. This study recruited 164 Russian participants (51 endurance and 48 power athletes; 65 controls). Vastus lateralis muscle fiber composition was assessed by immunohistochemistry. Slow-twitch muscle fiber percentage (STMF%) was significantly greater in endurance than power athletes and non-athletes, and in non-athlete females than males. STMF% was positively associated with athletes’ training frequency, non-athletes’ and endurance athletes’ age, endurance athletes’ competition level and chest depth, and power athletes’ training age. STMF% was negatively associated with diastolic blood pressure in power athletes and with systolic blood pressure and reaction time in non-athletes. In all participants, STMF% was positively associated with age, tolerance to long distance exercise, chest depth and fracture incidence, and negatively with systolic blood pressure and resting heart rate. Age, sex and training frequency explained 10.6% and 13.2% of the variance in STMF% in endurance and power athletes, respectively. This is one of the most comprehensive studies involving athletes and untrained subjects and provides novel information concerning associations of increased STMF percentage with lower resting heart rate, better tolerance to long distances, faster reaction time and larger chest depth. On the other hand, the increased percentage of fast-twitch muscle fibers was associated with rare fracture incidence.

Cardiac rehabilitation in older patients: Indication or limitation?

ObjectiveTo assess the clinical impact of a cardiac rehabilitation program in an older population. MethodsThis is a retrospective analysis of 731 coronary patients who attended phase 2 of a cardiac rehabilitation program between January 2009 and December 2016. We compared the response to the program of older (≥65 years) and younger (<65 years) patients, analyzing changes in metabolic profile (including body mass index, waist circumference and lipid profile), exercise capacity, cardiac autonomic regulation parameters (such as chronotropic index and resting heart rate), and health-related quality of life scores. ResultsOlder patients represented 15.9% of our cohort. They showed significant reductions in waist circumference (male patients: 98.0±7.9 cm vs. 95.9±7.9 cm, p<0.001; female patients: 90.5±11.4 cm vs. 87.2±11.7 cm, p<0.001), LDL cholesterol (102.5 [86.3-128.0] mg/dl vs. 65.0 [55.0-86.0] mg/dl, p<0.001) and triglycerides (115.0 [87.8-148.5] mg/dl vs. 97.0 [81.8-130.0] mg/dl, p<0.001). Post-training data also showed a noticeable improvement in older patients’ exercise capacity (7.6±1.8 METs vs. 9.3±1.8 METs, p<0.001), along with a higher chronotropic index and lower resting heart rate. Additionally, health-related quality of life indices improved in older subjects. However, our overall analysis found no significant differences between the groups in changes of the studied parameters. ConclusionOlder coronary patients benefit from cardiac rehabilitation interventions, similarly to their younger counterparts. Greater involvement of elderly patients in cardiac rehabilitation is needed to fully realize the therapeutic and secondary preventive potential of such programs.