A Systematic Review and Meta-Analysis of Randomized Trials to Evaluate the Impact of Exercise on Heart Rate Variability Post-Bariatric Surgery.

Bariatric surgery is an approach used to treat patients with obesity in a small minority of eligible patients. Non-pharmacological therapies are important to maintain decent health status post-bariatric surgery. We performed a systematic review with meta-analysis to evaluate the effects of exercise on heart rate variability (HRV) in patients submitted to bariatric surgery. The searches were made via MEDLINE/PubMed (via the National Library of Medicine), EMBASE, Web of Science, and Scopus databases. We included non-blind, single-, or double-blind randomized control trials in patients older than 18 years of age submitted to bariatric surgery. The intervention group should be submitted to an exercise training protocol, including aerobic, strength, and other exercise modality after bariatric surgery. We documented 245 studies, and after screening and eligibility phases, only 4 were included. We observed no significant change for the SDNN: subtotal = 19.74 (CI: -4.98, 44.45), p = 0.12, I2 = 85% (very low quality of evidence); pNN50: subtotal = 13.09 (CI: -9.17, 35.35), p = 0.25, I2 = 93% (very low quality of evidence); RMSSD: subtotal = 8.44 (CI: -3.61, 25.50), p = 0.17, I2 = 95% (very low quality of evidence); SD1: subtotal = 9.36 (CI: -4.48, 23.21), p = 0.19, I2 = 96% (very low quality of evidence). We could not detect significant effects of exercise on resting HRV after bariatric surgery. The low certainty of the results via the evidence level analysis suggest further studies might be beneficial.

The effect of paroxetine on heart rate variability in patients with major depressive disorder: A systematic review and meta-analysis.

INTRODUCTION: The impacts of antidepressant pharmacotherapies on cardiovascular risk are unclear. We completed a systematic review with meta-analysis to assess the effect of paroxetine on heart rate variability (HRV) in patients with major depressive disorder (MDD). METHODS: The searches were accomplished via EMBASE, MEDLINE/PubMed (using the National Library of Medicine), Cochrane Library, CINAHL, Scopus, and Web of Science databases. We included non-blind, single, or double-blind randomized control trials in patients older than 18 diagnosed with MDD. Paroxetine needs to be enforced as a chronic therapeutic medication. We included individual studies that investigated resting HRV. RESULTS: We documented 402 studies, only following screening and eligibility phases; only six were included (five studies in the meta-analysis). No significant change was noticed for the SDNN index: subtotal = 8.23 [CI: -2.17, 18.63], p = 0.12, I2 = 54 % (very low quality of evidence). A significant change was distinguished for the LF index: subtotal = 0.74 [CI: 0.33, 1.15], p = 0.0004, I2 = 0 % (low quality of evidence). A significant alteration was perceived for the HF index: subtotal = 0.33 [CI: 0.06, 0.6], p = 0.02, I2 = 0 % (low quality of evidence). CONCLUSION: Meta-analysis demonstrated that paroxetine could advance HRV in MDD patients. Nevertheless, our supposition is founded only on statistical analysis and the very low quality of evidence breakdown reinforces the necessity for further studies to confirm or reject this theory.

Effects of dietary inorganic nitrate on blood pressure during and post-exercise recovery: A systematic review and meta-analysis of randomized placebo-controlled trials.

OBJECTIVES: A systematic review with meta-analysis was completed to study the effects of dietary inorganic nitrate (NO3-) oral ingestion from vegetables and salts on blood pressure responses during and following exercise. BACKGROUND: NO3- is a hypotensive agent with the potential to reduce blood pressure peaks during exercise and amplify exercise-induced hypotensive effects. Several randomized and controlled trials have investigated the effects of NO3- on hemodynamic responses to physical exercise, however this still has yet to be studied systematically. METHODS: The searches were conducted on EMBASE, Medline, and SPORTSDiscus databases. The study included masked randomized controlled trials (RCTs) with participants ≥18 years old. The NO3-intervention group received at least 50 mg NO3-/day with similar sources amid NO3- and placebo conditions. Included studies reported systolic blood pressure (SBP) or diastolic blood pressure (DBP) values during or following exercise performance. RESULTS: 1903 studies were identified, and twenty-six achieved the inclusion criteria. NO3- daily dosages ranged from 90 to 800 mg/day. Throughout exercise, SBP had smaller increases in the NO3- group (-2.81 mmHg (95%CI: -5.20 to -0.41), p=0.02. DBP demonstrated lower values in the NO3- group (-2.41 mmHg (95%CI: -4.02 to -0.79), p=0.003. In the post-exercise group, the NO3- group presented lower SBP values (-3.53 mmHg (95%CI: -5.65 to 1.41), p=0.001, while no changes were identified in DBP values between NO3- and placebo groups (p=0.31). Subgroup meta-analysis revealed that SBP baseline values, exercise type, duration of NO3- ingestion, and its dosages mediated blood pressure responses during and following exercise. CONCLUSIONS: NO3- ingestion prior to exercise attenuated the increases in SBP and DBP during exercise, and increased the decline in SBP after exercise. These results are dependent on factors that moderate the blood pressure responses (e.g., health status, type of exercise, resting blood pressure values).

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.

Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis.

BACKGROUND: The repercussions on oxidative and inflammatory stress markers under the effects of arginine and citrulline in response to exercise are not fully reached. We completed a systematic review to investigate the effects of L-Citrulline or L-Arginine on oxidative stress and inflammatory biomarkers following exercise. EMBASE, MEDLINE (PubMed), Cochrane Library, CINAHL, LILACS, and Web of Science databases were used to record the trials. This study includes randomized controlled trials (RCTs) and non-RCTs with subjects over 18 years old. Those under the intervention protocol consumed L-Citrulline or L-Arginine, and the controls ingested placebo. We recognized 1080 studies, but only 7 were included (7 studies in meta-analysis). We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%. In the sub-group "L-Arginine" we found a subtotal = -0.29 [-0.71, 0.12], p = 0.16, and heterogeneity = 0%. For the "L-Citrulline" subgroup we observed a subtotal = 0.00 [-0.67, 0.67], p = 1.00, and heterogeneity was not applicable. No differences were observed between groups (p = 0.47), and I² = 0%) or in antioxidant activity (subtotal = -0.28 [-1.65, 1.08], p = 0.68, and heterogeneity = 0%). In the "L-Arginine" sub-group, we found a subtotal = -3.90 [-14.18, 6.38], p = 0.46, and heterogeneity was not applicable. For the "L-Citrulline" subgroup, we reported a subtotal = -0.22 [-1.60, 1.16], p = 0.75, and heterogeneity was not applicable. No differences were observed between groups (p = 0.49), and I² = 0%), inflammatory markers (subtotal = 8.38 [-0.02, 16.78], p = 0.05, and heterogeneity = 93%. Tests for subgroup differences were not applicable, and anti-inflammatory markers (subtotal = -0.38 [-1.15, 0.39], p = 0.34 and heterogeneity = 15%; testing for subgroup differences was not applicable). In conclusion, our systematic review and meta-analysis found that L-Citrulline and L-Arginine did not influence inflammatory biomarkers and oxidative stress after exercise.

HRV analysis: undependability of approximate entropy at locating optimum complexity in malnourished children.

INTRODUCTION: Approximate Entropy is an extensively enforced metric to evaluate chaotic responses and irregularities of RR intervals sourced from an eletrocardiogram. However, to estimate their responses, it has one major problem - the accurate determination of tolerances and embedding dimensions. So, we aimed to overt this potential hazard by calculating numerous alternatives to detect their optimality in malnourished children. MATERIALS AND METHODS: We evaluated 70 subjects split equally: malnourished children and controls. To estimate autonomic modulation, the heart rate was measured lacking any physical, sensory or pharmacologic stimuli. In the time series attained, Approximate Entropy was computed for tolerance (0.1→0.5 in intervals of 0.1) and embedding dimension (1→5 in intervals of 1) and the statistical significances between the groups by their Cohen's ds and Hedges's gs were totalled. RESULTS: The uppermost value of statistical significance accomplished for the effect sizes for any of the combinations was -0.2897 (Cohen's ds) and -0.2865 (Hedges's gs). This was achieved with embedding dimension = 5 and tolerance = 0.3. CONCLUSIONS: Approximate Entropy was able to identify a reduction in chaotic response via malnourished children. The best values of embedding dimension and tolerance of the Approximate Entropy to identify malnourished children were, respectively, embedding dimension = 5 and embedding tolerance = 0.3. Nevertheless, Approximate Entropy is still an unreliable mathematical marker to regulate this.

Slow breathing influences cardiac autonomic responses to postural maneuver: Slow breathing and HRV.

Chronic slow breathing has been reported to improve Heart Rate Variability (HRV) in patients with cardiovascular disorders. However, it is not clear regarding its acute effects on HRV responses on autonomic analysis. We evaluated the acute effects of slow breathing on cardiac autonomic responses to postural change manoeuvre (PCM). The study was conducted on 21 healthy male students aged between 18 and 35 years old. In the control protocol, the volunteer remained at rest seated for 15 min under spontaneous breathing and quickly stood up within 3 s and remained standing for 15 min. In the slow breathing protocol, the volunteer remained at rest seated for 10 min under spontaneous breath, then performed slow breathing for 5 min and rapidly stood up within 3 s and remained standing for 15 min. Slow breathing intensified cardiac autonomic responses to postural maneuver.

Symbolic analysis of heart rate variability and its interaction with p-value of normality tests applied on RR intervals / Análise simbólica da variabilidade da frequência cardíaca e sua interação com valor-p de testes de normalidade aplicado em intervalos RR

OBJECTIVE: A previous study suggested that the p-value of normality test applied to RR intervals is an index able to quantify Heart Rate Variability (HRV) through correlation of traditional time and frequency domain indices. We investigate the association between the p-value of normality test applied in RR intervals and symbolic analysis of HRV. METHOD: We evaluated 32 healthy women between 18 and 30 years old. RR intervals were used for HRV analysis and we performed symbolic analysis, where RR intervals are joined by symbols. Sets of three consecutive symbols (RR intervals) were grouped into four types of clusters, as follows: 1. Three equal symbols (zero variation); 2: two equal, one divergent symbol (one variation); 3. Three different symbols monotonically ascending or descending (two like variations); 4. Three different symbols, forming a peak or a trough (two unlike variations). Frequency of occurrence of each type of cluster was calculated. Normality tests were applied to all RR intervals and the p-value was calculated. We computed the correlations between the p-value of normality test and symbolic analysis of HRV. RESULTS: Correlation coefficients between the p-value of normality test from Kolmorogov-Smirnov test and the four types of clusters showed no correlation for any of them. Likewise, the correlation coefficient index between the p-value of normality test calculated from the Shapiro-Wilk test and symbolic analysis produced no significant results for any of the four types of clusters. CONCLUSION: There was no significant correlation between the p-value of normality test and HRV symbolic analysis. The physiological significance of this result is that the PNT is not related to chaotic behavior of HRV.

OBJETIVO: Um estudo anterior sugeriu que o valor "p" do teste de normalidade (PNT) aplicado a intervalos RR é um índice capaz de quantificar variabilidade da frequência cardíaca através da correlação tradicional dos índices de tempo e frequência. Investigamos a associação entre o teste PNT aplicado a intervalos RR e a análise simbólica da variabilidade da frequência cardíaca. MÉTODO: Foram avaliadas 32 mulheres saudáveis entre 18 e 30 anos de idade. Os intervalos RR foram utilizados para análise da variabilidade da frequência cardíaca; foi realizada uma análise simbólica, onde intervalos RR são unidos por símbolos. Grupos de três símbolos consecutivos foram agrupados em quatro tipos de aglomerados, a saber: 1: três símbolos iguais (variação zero); 2: dois símbolos iguais, um divergente (uma variação); 3: três símbolos diferentes, monotonicamente crescentes ou decrescentes (duas variações iguais); 4: três símbolos diferentes, formando um pico ou uma calha (duas variações desiguais). Foi calculada a frequência de ocorrência de cada tipo de cluster. Testes de normalidade foram aplicados a todos os intervalos RR e o valor de "p" foi calculado. Calculamos as correlações entre o PNT e análise simbólica de HRV. RESULTADOS: Os coeficientes de correlação entre PNT de teste Kolmorogov-Smirnov e os quatro tipos de clusters não mostraram correlação com qualquer um deles. Da mesma forma, o coeficiente de correlação entre o índice PNT calculado a partir do teste de Shapiro-Wilk e a análise simbólica não produziu resultados significativos para qualquer dos quatro tipos de aglomerados. CONCLUSÃO: Não houve correlação significativa entre o PNT e análise simbólica da variabilidade da frequência cardíaca. O significado fisiológico deste resultado é que o PNT não está relacionado ao comportamento caótico da VFC.