Increases in vagal-related indices of resting and post-exercise HRV, post-exercise HRR, and HR acceleration are evident when positive adaptation to training has occurred, allowing for increases in performance. However, increases in post-exercise HRV and HRR also occur in response to overreaching, demonstrating that additional measures of training tolerance may be required to determine whether training-induced changes in these parameters are related to positive or negative adaptations. Resting HRV is largely unaffected by overreaching, although this may be the result of methodological issues that warrant further investigation. HR acceleration appears to decrease in response to overreaching training, and thus may be a potential indicator of training-induced fatigue.
Objective: Impaired endothelial function in obesity may reduce blood flow to sites of metabolism, contributing to impaired fat oxidation and insulin resistance. This study investigated the effects of cocoa flavanols and regular exercise, interventions known to improve endothelial function, on cardiometabolic function and body composition in obese individuals. Design: Overweight and obese adults were randomly assigned to high-flavanol cocoa (HF, 902 mg flavanols), HF and exercise, low-flavanol cocoa (LF, 36 mg flavanols), or LF and exercise for 12 weeks (exercise duration was 3 Â 45 min per week at 75% of age-predicted maximum heart rate). Body composition was assessed by dual-energy X-ray absorptiometry at 0 and 12 weeks. Brachial artery flow-mediated dilatation (FMD), supine blood pressure (BP) and fasting plasma insulin, and glucose levels were assessed at 0, 6 and 12 weeks, respectively. Insulin sensitivity/resistance was determined using the modified homeostasis model assessment of insulin resistance (HOMA2). Results: A total of 49 subjects (M ¼ 18; F ¼ 31) completed the intervention. Baseline averages were as follows: body mass index ¼ 33.5 kg/m 2 ; BP ¼ 123/76 mm Hg; HOMA2 ¼ 2.4; FMD ¼ 4.3%; rate of fat oxidation during exercise ¼ 0.34 g min À1 ; abdominal fat ¼ 45.7% of total abdominal mass. Compared to LF, HF increased FMD acutely (2 h post-dose) by 2.4% (Po0.01) and chronically (over 12 weeks; Po0.01) by 1.6% and reduced insulin resistance by 0.31% (Po0.05), diastolic BP by 1.6 mm Hg and mean arterial BP by 1.2 mm Hg (Po0.05), independent of exercise. Regular exercise increased fat oxidation during exercise by 0.10 g min À1 (Po0.01) and reduced abdominal fat by 0.92% (Po0.05). Conclusion: Although HF consumption was shown to improve endothelial function, it did not enhance the effects of exercise on body fat and fat metabolism in obese subjects. However, it may be useful for reducing cardiometabolic risk factors in this population.
Considering the relationship between VO2max and various markers of health, the use of step tests as a measure of health in both the general adult population and rehabilitation settings is advocated. Step tests provide a simple, effective and ecologically valid method of submaximally assessing VO2max that can be implemented in a variety of situations within the general adult population. Future research is needed to assess the reliability of the majority of the step-test procedures reviewed. Based on the validity measures, submaximal step-test protocols are an acceptable means of estimating VO2max in the generally healthy adult population. For tracking changes in cardiorespiratory fitness, the Chester Step test appears to be an appropriate tool due to its high test-retest reliability.
Anthocyanins are of interest due to their anti-oxidative and vasodilatory properties. Earlier reviews have shown that berries and other anthocyanin rich foods or extracts can improve vascular health, however the effect of anthocyanins on vascular function has not yet been reviewed. To address this gap in the literature, we conducted a systematic review and meta-analysis of randomised-controlled trials examining anthocyanin-rich foods or extracts on measures of vascular reactivity and/or stiffness in adults. Data from 24 studies were pooled as standardized mean difference (SMD) with 95% confidence intervals (CI). Anthocyanin consumption significantly improved flow-mediated dilation (FMD) following acute (SMD: 3.92%, 95% CI: 1.47, 6.38, p = 0.002; I2 = 91.8%) and chronic supplementation (SMD: 0.84%, 95% CI: 0.55, 1.12, p = 0.000; I2 = 62.5%). Pulse wave velocity was improved following acute supplementation only (SMD: −1.27 m/s, 95% CI: −1.96, −0.58, p = 0.000; I2 = 17.8%). These results support the findings of previous reviews that anthocyanin rich foods or extracts may indeed improve vascular health, particularly with respect to vascular reactivity measured by FMD. More research is required to determine the optimal dosage, and the long-term effects of consumption.
Background:Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex condition with no reliable diagnostic biomarkers. Studies have shown evidence of autonomic dysfunction in patients with ME/CFS, but results have been equivocal. Heart rate (HR) parameters can reflect changes in autonomic function in healthy individuals; however, this has not been thoroughly evaluated in ME/CFS.Methods:A systematic database search for case-control literature was performed. Meta-analysis was performed to determine differences in HR parameters between ME/CFS patients and controls.Results:Sixty-four articles were included in the systematic review. HR parameters assessed in ME/CFS patients and controls were grouped into ten categories: resting HR (RHR), maximal HR (HRmax), HR during submaximal exercise, HR response to head-up tilt testing (HRtilt), resting HR variability (HRVrest), HR variability during head-up tilt testing (HRVtilt), orthostatic HR response (HROR), HR during mental task(s) (HRmentaltask), daily average HR (HRdailyaverage), and HR recovery (HRR) Meta-analysis revealed RHR (MD ± 95% CI = 4.14 ± 1.38, P < .001), HRtilt (SMD ± 95% CI = 0.92 ± 0.24, P < .001), HROR (0.50 ± 0.27, P < .001), and the ratio of low frequency power to high frequency power of HRVrest (0.39 ± 0.22, P < .001) were higher in ME/CFS patients compared to controls, while HRmax (MD ± 95% CI = –13.81 ± 4.15, P < .001), HR at anaerobic threshold (SMD ± 95% CI = –0.44 ± 0.30, P = 0.005) and the high frequency portion of HRVrest (–0.34 ± 0.22, P = .002) were lower in ME/CFS patients.Conclusions:The differences in HR parameters identified by the meta-analysis indicate that ME/CFS patients have altered autonomic cardiac regulation when compared to healthy controls. These alterations in HR parameters may be symptomatic of the condition.
ObjectiveTo assess whether physically active yoga is superior to waitlist control, treatment as usual and attention control in alleviating depressive symptoms in people with a diagnosed mental disorder recognised by the Diagnostic and Statistical Manual of Mental Disorders (DSM).DesignSystematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.Data sourcesData were obtained from online databases (MEDLINE, EMBASE, PsychINFO, CENTRAL, EMCARE, PEDro). The search and collection of eligible studies was conducted up to 14 May 2019 (PROSPERO registration No CRD42018090441).Eligibility criteria for selecting studiesWe included randomised controlled trials with a yoga intervention comprising ≥50% physical activity in adults with a recognised diagnosed mental disorder according to DSM-3, 4 or 5.Results19 studies were included in the review (1080 participants) and 13 studies were included in the meta-analysis (632 participants). Disorders of depression, post-traumatic stress, schizophrenia, anxiety, alcohol dependence and bipolar were included. Yoga showed greater reductions in depressive symptoms than waitlist, treatment as usual and attention control (standardised mean difference=0.41; 95% CI −0.65 to −0.17; p<0.001). Greater reductions in depressive symptoms were associated with higher frequency of yoga sessions per week (β=−0.44, p<0.01).
Vagally mediated HRV during standing increased in response to functional overreaching (indicating potential parasympathetic hyperactivity) and also to improvements in performance. Thus, additional measures such as training tolerance are required to interpret changes in vagally mediated HRV.
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