Does the number of sets in a resistance exercise session affect the fast and slow phases of post-exercise cardiac autonomic recovery?

Abstract Aims: The purpose of this study was to evaluate the acute effects of different resistance exercise (RE) volumes on postexercise cardiac autonomic modulation in men. Methods: Ten young men (25.5 ± 4.9 years, 24.8 ± 2.1 kg/m2) performed 3 trials of RE with 1, 2 or 3 sets (48-72 h between each trial) of 10-12 repetitions (70% of the one-maximum repetition) of bench press, leg press, and barbell row. Heart rate variability (HRV) was assessed at the 1st and 5th minutes of recovery (fast phase) and 3 consecutive 5-minute intervals from the 5th to 20th minute of recovery (slow phase). Parasympathetic and global modulations were assessed using the SD1 and SD2 indices of HRV, respectively. The comparison of the interventions was performed using the Friedman and Wilcoxon tests (p<0.05). Results: Lower parasympathetic modulation was identified after 2 and 3 sets compared to 1 set in both the fast and slow recovery phases (p= 0.004-0.05). Lower global modulation was identified after 3 sets compared to 1 set in both fast and slow recovery phases (p= 0.005-0.01). No differences in post-exercise parasympathetic and global modulation were observed between 2 and 3 sets. Conclusion: We concluded that 2 and 3 sets of RE compared to 1 set promoted higher autonomic reduction on the post-exercise phase, which should be considered by coaches when prescribing an RE program for untrained participants or intend to manipulate the postexercise organic recovery.

Sympatho-Vagal Imbalance is Associated with Sarcopenia in Male Patients with Heart Failure / Desequilíbrio Simpático-Vagal está Associado com Sarcopenia em Pacientes do Sexo Masculino com Insuficiência Cardíaca

Abstract Background: Resting sympathetic hyperactivity and impaired parasympathetic reactivation after exercise have been described in patients with heart failure (HF). However, the association of these autonomic changes in patients with HF and sarcopenia is unknown. Objective: The aim of this study was to evaluate the impact of autonomic modulation on sarcopenia in male patients with HF. Methods: We enrolled 116 male patients with HF and left ventricular ejection fraction < 40%. All patients underwent a maximal cardiopulmonary exercise testing. Maximal heart rate was recorded and delta heart rate recovery (∆HRR) was assessed at 1st and 2nd minutes after exercise. Muscle sympathetic nerve activity (MSNA) was recorded by microneurography. Dual-energy X-ray absorptiometry was used to measure body composition and sarcopenia was defined by the sum of appendicular lean muscle mass (ALM) divided by height in meters squared and handgrip strength. Results: Sarcopenia was identified in 33 patients (28%). Patients with sarcopenia had higher MSNA than those without (47 [41-52] vs. 40 [34-48] bursts/min, p = 0.028). Sarcopenic patients showed lower ∆HRR at 1st (15 [10-21] vs. 22 [16-30] beats/min, p < 0.001) and 2nd min (25 [19-39] vs. 35 [24-48] beats/min, p = 0.017) than non-sarcopenic. There was a positive correlation between ALM and ∆HRR at 1st (r = 0.26, p = 0.008) and 2nd min (r = 0.25, p = 0.012). We observed a negative correlation between ALM and MSNA (r = -0.29, p = 0.003). Conclusion: Sympatho-vagal imbalance seems to be associated with sarcopenia in male patients with HF. These results highlight the importance of a therapeutic approach in patients with muscle wasting and increased peripheral sympathetic outflow.

Resumo Fundamento: Hiperatividade simpática de repouso e uma reativação parassimpática diminuída pós-exercício têm sido descritas em pacientes com insuficiência cardíaca (IC). No entanto, a associação dessas alterações autonômicas em pacientes com IC sarcopênicos ainda não são conhecidas. Objetivo: O objetivo deste estudo foi avaliar o impacto da modulação autonômica sobre sarcopenia em pacientes com IC do sexo masculino. Métodos: Foram estudados 116 pacientes com IC e fração de ejeção ventricular esquerda inferior a 40%. Todos os pacientes foram submetidos ao teste de exercício cardiopulmonar máximo. A frequência cardíaca máxima foi registrada, e o delta de recuperação da frequência cardíaca (∆RFC) foi avaliado no primeiro e no segundo minuto após o exercício. A atividade nervosa simpática muscular (ANSM) foi registrada por microneurografia. A Absorciometria Radiológica de Dupla Energia foi usada para medir composição cpororal, e a sarcopenia definida como a soma da massa muscular apendicular (MMA) dividida pela altura em metros ao quadrado e força da mão. Resultados: A sarcopenia foi identificada em 33 pacientes (28%). Os pacientes com sarcopenia apresentaram maior ANSM que aqueles sem sarcopenia - 47 (41-52) vs. 40 (34-48) impulsos (bursts)/min, p = 0,028). Pacientes sarcopênicos apresentaram ∆RFC mais baixo no primeiro [15 (10-21) vs. 22 (16-30) batimentos/min, p < 0,001) e no segundo [25 (19-39) vs. 35 (24-48) batimentos/min, p = 0,017) minuto que pacientes não sarcopênicos. Observou-se uma correlação positiva entre a MMA e a ANSM (r = -0,29; p = 0,003). Conclusão: Um desequilíbrio simpático-vagal parece estar associado com sarcopenia em pacientes com IC do sexo masculino. Esses resultados destacam a importância de uma abordagem terapêutica em pacientes com perda muscular e fluxo simpático periférico aumentado.

Reliability of heart rate variability threshold and parasympathetic reactivation after a submaximal exercise test

Abstract The objective of this study was to evaluate reproducibility of heart rate variability threshold (HRVT) and parasympathetic reactivation in physically active men (n= 16, 24.3 ± 5.1 years). During the test, HRVT was assessed by SD1 and r-MSSD dynamics. Immediately after exercise, r-MSSD was analyzed in segments of 60 seconds for a period of five minutes. High absolute and relatively reproducible analysis of HRVT were observed, as assessed by SD1 and r-MSSD dynamics (ICC = 0.92, CV = 10.8, SEM = 5.8). During the recovery phase, a moderate to high reproducibility was observed for r-MSSD from the first to the fifth minute (ICC = 0.69-0.95, CV = 7.5-14.2, SEM = 0.07-1.35). We conclude that HRVT and r-MSSD analysis after a submaximal stress test are highly reproducible measures that might be used to assess the acute and chronic effects of exercise training on cardiac autonomic modulation during and/or after a submaximal stress test.(AU)

Metabolic Syndrome Is Associated with Delayed Heart Rate Recovery after Exercise

Heart rate (HR) recovery after exercise is a function of vagal reactivation, and its impairment is a predictor of overall mortality and adverse cardiovascular events. While metabolic syndrome is associated with sympathetic overactivity, little is known about the relationship between metabolic syndrome and HR recovery. A symptom-limited exercise stress test in healthy subjects (n=1, 434) was used to evaluate HR recovery. Metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (NCEP ATP-III) criteria. Seventeen percent of subjects had > or =3 criteria for metabolic syndrome. HR recovery was lower in men than women and in smokers than nonsmokers. The subject with metabolic syndrome (vs. without) showed lower HR recovery (10.3+/-11.6 vs. 13.6+/-9.7 per minute) and higher resting HR (64.3+/-10.3 vs. 61.6+/-9.1 per minute). HR recovery correlated inversely to age (r=-0.25, p<0.0001), but not to resting HR or maximal oxygen uptake. Delayed HR recovery was associated with metabolic syndrome after an adjustment for age, sex, resting HR and smoking (p<0.01). Metabolic syn-drome is associated with impaired vagal reactivation. Adverse cardiovascular out-comes associated with metabolic syndrome may be mediated by the failure of vagal reactivation in addition to sympathetic overactivity.