Estimating the Effect of Aerobic Exercise Training on Novel Lipid Biomarkers: A Systematic Review and Multivariate Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Aerobic exercise training (AET) prescribed as lipid management treatment positively affects the standard lipid profile and reduces cardiovascular disease (CVD) risk. Apolipoproteins, lipid and apolipoprotein ratios, and lipoprotein sub-fractions may more effectively predict CVD risk than the standard lipid profile but an AET response in these biomarkers has not been established. OBJECTIVES: We conducted a quantitative systematic review of randomised controlled trials (RCTs) to (1) determine the effects of AET on lipoprotein sub-fractions, apolipoproteins and relevant ratios; and (2) identify study or intervention covariates associated with change in these biomarkers. METHODS: We searched PubMed, EMBASE, all Web of Science and EBSCO health and medical online databases from inception to 31 December 2021. We included published RCTs of adult humans with ≥ 10 per group of participants; an AET intervention duration ≥ 12 weeks of at least moderate intensity (> 40% maximum oxygen consumption); and reporting pre/post measurements. Non-sedentary subjects, or those with chronic disease other than Metabolic Syndrome factors, or pregnant/lactating, as well as trials testing diet/medications, or resistance/isometric/unconventional training interventions, were excluded. RESULTS: Fifty-seven RCTs totalling 3194 participants were analysed. Multivariate meta-analysis showed AET significantly raised antiatherogenic apolipoproteins and lipoprotein sub-fractions (mmol/L mean difference (MD) 0.047 (95% confidence interval (CI) 0.011, 0.082), P = .01); lowered atherogenic apoliproteins and lipoprotein sub-fractions (mmol/L MD - 0.08 (95% CI - 0.161, 0.0003), P = .05); and improved atherogenic lipid ratios (MD - 0.201 (95% CI - 0.291, - 0.111), P < .0001). Multivariate meta-regression showed intervention variables contributed to change in lipid, sub-fraction, and apoliprotein ratios. CONCLUSION: Aerobic exercise training positively impacts atherogenic lipid and apolipoprotein ratios, alipoproteins, and lipoprotein sub-fractions; and antiatherogenic apolipoproteins and lipoprotein sub-fractions. Cardiovascular disease risk predicted by these biomarkers may be lowered when AET is prescribed as treatment or prevention. PROSPERO ID: CRD42020151925.

Hospitalisation costs associated with heart failure with preserved ejection fraction (HFpEF): a systematic review.

Heart failure with preserved ejection fraction (HFpEF) is problematic to treat, with guidelines for HFpEF management concentrated on treating prevalent comorbidities. The aim of this study is to conduct a systematic review of the economic burden of hospitalisation for HFpEF. We conducted a systematic literature search from 2001, when HFpEF was first identified as an isolated diagnosis, up to July 1, 2020. Databases searched include PubMed, Medline, EMBASE, EBSCO, National Health Service Economic Evaluation and the National Bureau of Economic Research. The primary outcome measure was hospitalisation costs related to HFpEF. A comprehensive search of the literature produced a total of 243 possible studies. A total of nine studies, six from the U.S., met inclusion criteria and were included in this review. All results are presented in United States Dollars (US$) for the financial year 2019. Costs of index (the first) hospitalisation ranged from mean US$8340 up to US$11,366 per admission and increased up to US$31,493 for those with comorbidities. Two studies reported 1-year costs, and these were US$27,174 and US$26,343, respectively. Hospitalisation accounts for approximately 80% of total costs of HFpEF treatment. The results of this systematic review reveal that published costs of HFpEF hospitalisation are limited to nine studies from a comprehensive database search. The costs of an initial HF hospitalisation are significant, and these costs increase when a person with HFpEF presents with comorbidities or other complications.

Determining the effect size of aerobic exercise training on the standard lipid profile in sedentary adults with three or more metabolic syndrome factors: a systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES: To estimate the change in the standard lipid profile (SLP) of adults diagnosed with ≥3 metabolic syndrome (MetS) factors following aerobic exercise training (AET); and to investigate whether study/intervention covariates are associated with this change. DESIGN: Systematic review with univariate meta-analysis and meta-regression. DATA SOURCES: English language searches of online databases from inception until July 2020. ELIGIBILITY CRITERIA: (1) Published randomised controlled human trials with study population ≥10 per group; (2) sedentary adults with ≥3 MetS factors but otherwise free of chronic disease, not pregnant/lactating; (3) AET-only intervention with duration ≥12 weeks; and (4) reporting pre-post intervention SLP outcomes. RESULTS: Various univariate meta-analyses pooled 48 data sets of 2990 participants. Aerobic exercise training significantly (P<.001) improved all lipids (mmol/L mean difference ranges, 95% CIs): total cholesterol, -0.19 (-0.26 to -0.12) to -0.29 (-0.36 to -0.21); triglycerides, -0.17 (-0.19 to -0.14) to -0.18 (-0.24 to -0.13); high-density lipoprotein-cholesterol (HDL-C), 0.05 (0.03 to 0.07) to 0.10 (0.05 to 0.15); and low-density lipoprotein-cholesterol (LDL-C), -0.12 (-0.16 to -0.9) to -0.20 (-0.25 to -0.14). Meta-regression showed that intensity may explain change in triglycerides and volume may explain change in HDL-C and LDL-C. CONCLUSION: Aerobic exercise training positively changes the SLP of sedentary and otherwise healthy adults with ≥3 MetS factors. Adjusting AET intervention training variables may increase the effects of AET on triglycerides and HDL-C. PROSPERO REGISTRATION NUMBER: CRD42020151925.

Effect of low- and high-protein maternal diets during gestation on reproductive outcomes in the rat: a systematic review and meta-analysis.

Studies with animal models have consistently demonstrated adverse health outcomes in offspring born following nutritional manipulation during gestation. However, the effects of gestational dietary protein modification on reproductive outcomes at birth are less clear. We, therefore, conducted a systematic review and meta-analysis of controlled trials to determine whether high- or low-protein diets are associated with altered reproductive outcomes in a commonly studied species, the rat. Included studies were identified through a systematic search using electronic databases and manual literature review to identify randomized studies published between June 1972 and March 2019. Thirty-two studies were identified and used to analyze the effects of low- and high-protein gestational diets on litter size, litter weight, gestational weight gain, and gestational feed intake. The results indicate that low-protein diets significantly reduced litter weight (P < 0.00001) and gestational weight gain (P < 0.0006), but did not influence litter size (P = 0.62) or gestational feed intake (P = 0.25). In contrast, high-protein diets were found to reduce gestational feed intake (P = 0.004) but did not influence litter size (P = 0.56), litter weight (P = 0.22), or gestational weight gain (P = 0.35). The results suggest that low but not high-protein gestational diets alter reproductive outcomes at birth in rats.

Physiological Responses to Heat Acclimation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The aim of this meta-analysis was to evaluate the effectiveness of heat acclimatization (HA) on time trial (TT) performance, maximum oxygen uptake (VO2max), exercise heart rate (HRE), time trials heart rate (HRTT), maximal heart rate (HRM), core temperature (TC), mean skin temperature (TS), thermal comfort (TComf), plasma volume (PV), blood lactate concentration and rate of perceived exertion (RPE). Cochrane-CENTRAL, EMBASE, CINAHL and PubMed databases and reference lists of included studies were searched for randomized controlled trials that investigated the efficacy of HA in athletes. Data were then extracted from the entered studies for analyses. A total of 11 randomised controlled trials (215 participants; mean age, 26.09 years; 91% men) were included after screening of 508 titles and abstracts and 19 full-text articles. The pooled standard mean difference (SMD) between the HA and non-HA groups were 0.50 (95% CI: 0.03 to 0.97, p = 0.04) for TT performance and 1 (95% CI: 1 to 2, p = 0.007) for HRTT. The pooled mean difference (MD) between the HA and non-HA groups were -7 (95% CI: -13 to -1, p = 0.03) for HRM. The changes in TComf and RPE were too small to be meaningful. There were no significant differences between the HA and non-HA groups for VO2max, HRE, TC, TS, PV and blood lactate concentration (all p > 0.05). This meta-analysis implies that HA may improve tolerance to discomfort during heat exposure, but may not necessarily improve the associated physiological markers of improved performance.

Is C-reactive protein elevated in obstructive sleep apnea? a systematic review and meta-analysis.

Purpose: This study examined whether circulating C-reactive protein (CRP) is elevated in obstructive sleep apnoea (OSA) independent of the confounding effects of comorbidities, smoking, body mass index (BMI), age and gender. Methods: A systematic review of the literature was performed using PubMed, Embase and Cochrane databases from 1 January 1997 to 1 November 2017 using the key words obstructive sleep apnoea and C-Reactive protein to identify full text English language studies that compared CRP in adult non-smoking OSA participants without comorbidities and adult healthy non-smoking control participants matched for BMI, age and gender. Data from eligible studies were subjected to meta-analysis using RevMan version 5.3. Results: Five studies (219 OSA participants, 116 controls) met the selection criteria. The total standard mean difference for circulating high sensitivity CRP was 0.61 mg/dL higher in OSA participants than in control participants (confidence interval: 0.38 to 0.84, p < 0.00001), with low between-studies heterogeneity (df = 7, p = 0.16, I2 = 33%) and minimal evidence of publication bias. Conclusions: CRP levels in non-smoking OSA participants without comorbidities were increased relative to levels in healthy matched non-smoking control participants, suggesting that pharyngeal or systemic inflammatory effects attributable to OSA may elevate CRP.

HIIT is not superior to MICT in altering blood lipids: a systematic review and meta-analysis.

OBJECTIVE: To compare the effects of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on adult lipid profiles; to identify training or participant characteristics that may determine exercise-induced change in total cholesterol (TC), triglycerides (TRG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). DESIGN: Systematic review and meta-analysis. DATA SOURCES: English language searches of several databases were conducted from inception until September 2019. ELIGIBILITY CRITERIA FOR EXCLUDING STUDIES: Inclusion: (1) published randomised controlled human trials with group population n≥5; (2) intervention duration ≥4 weeks; (3) comparing HIIT with MICT; and (4) reporting pre-post intervention lipid measurements. Exclusion: subjects with chronic disease, <18 years, pregnant/lactating, in elite athletic training; and studies with a dietary or pharmaceutical intervention component. RESULTS: Twenty-nine data sets (mmol/L) of 823 participants were pooled and analysed. Neither HIIT nor MICT was better in decreasing TC (0.10 (-0.06 to 0.19), p=0.12, I2=0%), TRG (-0.05 (-0.11 to 0.01), p=0.10, I2=0%), LDL-C (0.05 (-0.06 to 0.17), p=0.37, I2=0%), or TC/HDL-C (-0.03 (-0.36 to 0.29), p=0.85, I2=0%). HIIT significantly raised HDL-C (0.07 (0.04 to 0.11), p<0.0001, I2=0%) compared with MICT. CONCLUSION: Neither HIIT nor MICT is superior for altering TC, TRG, or LDL-C, or TC-HDL-C ratio. Compared with MICT, HIIT appeared to significantly improve HDL-C. Clinicians may prescribe either protocol to encourage participation in exercise and reduce cardiovascular risk. To raise HDL-C, HIIT may result in a larger effect size compared with MICT. PROSPERO REGISTRATION NUMBER: CRD42019136722.

Anaerobic metabolism of inspiratory muscles in COPD.

OBJECTIVE: The purpose of this study was to determine if the respiratory muscles of patients with COPD could be made to function anaerobically, as evidenced by an increase in arterial blood lactate concentration ([lactate](a)) during specific loading of the inspiratory muscles and, if so, the effect of a programme of high-intensity inspiratory muscle training on this function. METHODS: In seven patients with COPD (FEV(1) = 33 +/- 14% of predicted), measurements of [lactate](a) were made each minute during progressive inspiratory threshold loading to voluntary exhaustion. These tests were performed before and after an 8-week programme of specific high-intensity inspiratory muscle training, combined with general whole-body exercise training. RESULTS: During inspiratory muscle loading small increases in [lactate](a) (0.83 +/- 0.32 mM) were observed in two subjects before training, and in five subjects after training (0.69 +/- 0.57 mM). [Lactate](a) only increased when the inspiratory work rate exceeded 6.9 cm H(2)O L/min per kilogram of body weight, and when baseline maximum inspiratory pressure exceeded 65 cm H(2)O. CONCLUSIONS: The results of this study demonstrated that it is possible for COPD patients to increase inspiratory muscle work rate to a level requiring a major energy contribution from anaerobic glycolytic metabolism. This was only seen when inspiratory muscle strength and endurance were sufficient to allow it. Some patients who failed to demonstrate an increase in [lactate](a) at baseline did so after a programme of high-intensity inspiratory muscle training.