Gudrun Dieberg

Intermittent versus continuous exercise training in chronic heart failure: A meta-analysis

INTRODUCTION We conducted a meta-analysis of randomized, controlled trials of combined strength and intermittent aerobic training, intermittent aerobic training only and continuous exercise training in heart failure patients. METHODS A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 19 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training, interval training and intermittent exercise training. RESULTS The included studies contained an aggregate of 446 patients, 212 completed intermittent exercise training, 66 only continuous exercise training, 59 completed combined intermittent and strength training and 109 sedentary controls. Weighted mean difference (MD) in Peak VO2 was 1.04mlkg(-1)min(-1) and (95% C.I.) was 0.42-1.66 (p=0.0009) in intermittent versus continuous exercise training respectively. Weighted mean difference in Peak VO2 was -1.10mlkg(-1)min(-1) (95% C.I.) was -1.83-0.37 p=0.003 for intermittent only versus intermittent and strength (combined) training respectively. In studies reporting VE/VCO2 for intermittent versus control groups, MD was -1.50 [(95% C.I. -2.64, -0.37), p=0.01] and for intermittent versus continuous exercise training MD was -1.35 [(95% C.I. -2.15, -0.55), p=0.001]. Change in peak VO2 was positively correlated with weekly exercise energy expenditure for intermittent exercise groups (r=0.48, p=0.05). CONCLUSIONS Combined strength and intermittent exercise appears superior for peak VO2 changes when compared to intermittent exercise of similar exercise energy expenditure.

Functional electrical stimulation for chronic heart failure: A meta-analysis

INTRODUCTION We conducted a meta-analysis of randomized, controlled trials of combined electrical stimulation versus conventional exercise training or placebo control in heart failure patients. METHODS A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training and functional electrical stimulation (FES). RESULTS FES produced inferior improvements in peak VO2 when compared to cycle training: mean difference (MD) -0.32 ml.kg(-1).min(-1) (95% C.I. -0.63 to -0.02 ml.kg(-1).min(-1), p=0.04), however FES elicited superior improvements in peak VO2: MD 2.30 ml.kg(-1).min(-1) (95% C.I. 1.98 to 2.62 ml.kg(-1).min(-1), p<0.00001); and six minute walk distance to sedentary care or sham FES; MD 46.9 m (95% C.I. 22.5 to 71.3m, p=0.0002). There was no difference in change in quality of life between cycling and FES, but FES elicited significantly larger improvements in Minnesota Living with Heart Failure score than placebo or sham treatment; MD 1.15 (95% C.I. 0.69 to 1.61, p<0.00001). Moreover, the total FES intervention hours were strongly correlated with change in peak VO2, (r=0.80, p=0.02). CONCLUSIONS Passive or active exercise is beneficial for patients with moderate to severe heart failure, but active cycling, or other aerobic/resistance activity is preferred in patients with heart failure who are able to exercise, and FES is the preferred modality in those unable to actively exercise. The benefits of FES may however, be smaller than those observed in conventional exercise training. Aggregate hours of electrical stimulation therapy were associated with larger improvements in cardio-respiratory fitness.

Efficacy of inspiratory muscle training in chronic heart failure patients: a systematic review and meta-analysis.

INTRODUCTION Inspiratory muscle training (IMT) offers an alternative to exercise training (ExT) in the most severely deconditioned heart failure patients who are unable to exercise. We conducted a meta-analysis to determine magnitude of change in peak VO2, six minute walk distance (6MWD), Quality of Life measured by the Minnesota Living with Heart Failure Questionnaire (MLWHFQ), maximal inspiratory pressure (PI max) and ventilatory equivalent for carbon dioxide (VE/VCO2 slope) with IMT. METHODS A systematic search was conducted of randomized, controlled trials of IMT therapy in CHF patients using Medline (Ovid) (1950-February 2012), Embase.com (1974-February 2012), Cochrane Central Register of Controlled Trials and CINAHL (1981-February 2012). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, inspiratory or respiratory muscle training, exercise training RESULTS The eleven included studies contained data on 287 participants: 148 IMT participants and 139 sham or sedentary control. Compared to control groups, CHF patients undergoing IMT showed a significant improvement in peak VO2 (+1.83 ml kg(-1) min(-1), 95% C.I. 1.33 to 2.32 ml kg(-1) min(-1), p<0.00001); 6 MWD (+34.35 m, 95% C.I. 22.45 to 46.24 m, p<0.00001); MLWHFQ (-12.25, 95% C.I. -17.08 to -7.43, p<0.00001); PImax (+20.01, 95% C.I. 13.96 to 26.06, p<0.00001); and VE/VCO2 slope (-2.28, 95% C.I. -3.25 to -1.30, p<0.00001). CONCLUSIONS IMT improves cardio-respiratory fitness and quality of life to a similar magnitude to conventional exercise training and may provide an initial alternative to the more severely de-conditioned CHF patients who may then transition to conventional ExT.

Isometric exercise training for blood pressure management: a systematic review and meta-analysis to optimize benefit

The objective of our study was to examine the effects of isometric resistance training (IRT) on resting blood pressure in adults. We conducted a systematic review and meta-analysis of randomized-controlled trials lasting ⩾2 weeks, investigating the effects of isometric exercise on blood pressure in healthy adults (aged ⩾18 years), published in a peer-reviewed journal between 1 January 1966 to 31 January 2015. We included 11 randomized trials, totaling 302 participants. The following reductions were observed after isometric exercise training; systolic blood pressure (SBP) mean difference (MD) −5.20 mm Hg (95% confidence interval (CI) −6.08 to −4.33, P<0.00001); diastolic blood pressure (DBP) MD −3.91 mm Hg (95% CI −5.68 to −2.14, P<0.0001); and mean arterial blood pressure (MAP) MD −3.33 mm Hg (95% CI −4.01 to −2.66, P<0.00001). Sub-analyses showed males tended to reduce MAP MD −4.13 mm Hg (95% CI −5.08 to −3.18) more than females. Subjects aged ⩾45 years demonstrated larger reductions in MAP MD −5.51 mm Hg (95% CI −6.95 to −4.06) than those <45 years. Subjects undertaking ⩾8 weeks of IRT demonstrated a larger reduction in SBP MD −7.26 mm Hg (95% CI −8.47 to −6.04) and MAP MD −4.22 mm Hg (95% CI −5.08 to −3.37) than those undertaking<8 weeks. Hypertensive participants in IRT demonstrated a larger reduction in MAP MD −5.91 mm Hg (95% CI −7.94 to −3.87) than normotensive participants MD −3.01 mm Hg (95% CI −3.73 to −2.29). Our study indicated that IRT lowers SBP, DBP and MAP. The magnitude of effect may be larger in hypertensive males aged ⩾45 years, using unilateral arm IRT for >8 weeks.

Validation of a new tool for the assessment of study quality and reporting in exercise training studies: TESTEX

Introduction:Several established tools are available to assess study quality and reporting of randomized controlled trials; however, these tools were designed with clinical intervention trials in mind. In exercise training intervention trials some of the traditional study quality criteria, such as participant or researcher blinding, are extremely difficult to implement. Methods:We developed the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX) – a study quality and reporting assessment tool, designed specifically for use in exercise training studies. Our tool is a 15-point scale (5 points for study quality and 10 points for reporting) and addresses previously unmentioned quality assessment criteria specific to exercise training studies. Results:There were no systematic differences between the summated TESTEX scores of each observer [H(2) = 0.392, P = 0.822]. There was a significant association between the summated TESTEX scores of the three observers, with almost perfect agreement between observers 1 and 2 [intra-class correlation coefficient (ICC) = 0.93, 95% confidence interval (CI) 0.82–0.97, P < 0.001], observers 1 and 3 (ICC = 0.96, 95% CI 0.89–0.98, P < 0.001) and observers 2 and 3 (ICC = 0.91, 95% CI 0.75–0.96, P < 0.001). Conclusions:The TESTEX scale is a new, reliable tool, specific to exercise scientists, that facilitates a comprehensive review of exercise training trials.

Effect of lifestyle intervention on the reproductive endocrine profile in women with polycystic ovarian syndrome: a systematic review and meta-analysis.

Polycystic ovarian syndrome (PCOS) affects 18–22% of women at reproductive age. We conducted a systematic review and meta-analysis evaluating the expected benefits of lifestyle (exercise plus diet) interventions on the reproductive endocrine profile in women with PCOS. Potential studies were identified by systematically searching PubMed, CINAHL and the Cochrane Controlled Trials Registry (1966–April 30, 2013) systematically using key concepts of PCOS. Significant improvements were seen in women receiving lifestyle intervention vs usual care in follicle-stimulating hormone (FSH) levels, mean difference (MD) 0.39 IU/l (95% CI 0.09 to 0.70, P=0.01), sex hormone-binding globulin (SHBG) levels, MD 2.37 nmol/l (95% CI 1.27 to 3.47, P<0.0001), total testosterone levels, MD −0.13 nmol/l (95% CI −0.22 to −0.03, P=0.008), androstenedione levels, MD −0.09 ng/dl (95% CI −0.15 to −0.03, P=0.005), free androgen index (FAI) levels, MD −1.64 (95% CI −2.94 to −0.35, P=0.01) and Ferriman–Gallwey (FG) score, MD −1.01 (95% CI −1.54 to −0.48, P=0.0002). Significant improvements were also observed in women who received exercise-alone intervention vs usual care in FSH levels, MD 0.42 IU/l (95% CI 0.11 to 0.73, P=0.009), SHBG levels, MD 3.42 nmol/l (95% CI 0.11 to 6.73, P=0.04), total testosterone levels, MD −0.16 nmol/l (95% CI −0.29 to −0.04, P=0.01), androstenedione levels, MD −0.09 ng/dl (95% CI −0.16 to −0.03, P=0.004) and FG score, MD −1.13 (95% CI −1.88 to −0.38, P=0.003). Our analyses suggest that lifestyle (diet and exercise) intervention improves levels of FSH, SHBG, total testosterone, androstenedione and FAI, and FG score in women with PCOS.

Exercise training for health-related quality of life in peripheral artery disease: A systematic review and meta-analysis

We sought to quantify whether health-related quality of life (HRQoL) is improved through exercise training in people with peripheral artery disease (PAD) and to clarify which prescriptions were optimal for improving HRQoL when compared to usual care. We conducted a systematic search (PubMed, CINAHL, Cochrane Central Register of Controlled Trials; 1966 – 31 August 2014). We only included randomized controlled trials (RCTs) of exercise training versus usual medical care in persons with PAD that included the Walking Impairment Questionnaire (WIQ) and Short-Form Health Survey component summary scores as outcomes. Of 15 RCTs, 1257 participants were studied: 543 participated in supervised exercise, with only 61 undertaking resistance training and 316 unsupervised exercise. When compared to controls, participants who completed any form of exercise training significantly improved their WIQ speed [mean difference (MD) 9.60 (95% CI 6.98 to 12.23, p<0.00001)]; WIQ distance [MD 7.41 (95% CI 4.49 to 10.33, p<0.00001)] and WIQ stair-climbing [MD 5.07 (95% CI 3.16 to 6.99, p<0.00001)]. Walking also significantly improved the Short-Form Physical Component Summary (SF-PCS) score when compared to controls [MD 1.24 (95% CI 0.48 to 2.01, p=0.001)], but not the Mental Component Summary (SF-MCS) score [MD –0.55 (95% CI –1.27 to 0.18, p=0.14)]. Exercise training improves the SF-PCS dimension, as well as perceived walking distance, speed and stair-climbing as measured by the WIQ, but not the SF-MCS score. Future studies should aim to blind assessors of such subjective measures, and study alternative modes and prescriptions of exercise alternative to walking.

The Effect of Lifestyle Intervention on Body Composition, Glycemic Control, and Cardiorespiratory Fitness in Polycystic Ovarian Syndrome: A Systematic Review and Meta-Analysis

INTRODUCTION Polycystic ovarian syndrome (PCOS) affects 18-22% women of reproductive age. We conducted a systematic review and meta-analysis to quantify expected benefits of lifestyle (exercise and dietary) interventions on various clinical outcomes in PCOS. METHODS Potential studies were identified by conducting systematic search of PubMed, the Cumulative Index to Nursing and Allied Health Literature, and Cochrane controlled trials registry (1966 to April 2013) using key concepts of PCOS, exercise, dietary and lifestyle interventions. RESULTS Significant improvements were seen in women who received lifestyle intervention vs. usual care, in body composition parameters of body mass index, mean difference (MD) = -0.12 kg.m(-2) (95% CI [-0.22, -0.03], p = .009), body mass MD = -3.42 kg (95% CI [-4.86, -1.99], p < .00001), waist circumference MD = -1.64 cm (95% CI [-2.09, -1.19], p < .00001), waist-hip ratio MD = -0.03 (95% CI [-0.05, -0.01], p = .0002), and body fat % MD = -1.71% (95% CI [-3.10, -0.32], p = .02). Insulin did not improve, MD = -1.21 pmol/L (95% CI [-3.06, -0.63], p = .20). Lipid profile did not improve, total cholesterol MD = -0.02 mmol/L (95% CI [-0.25, 0.21], p = .89). C-reactive protein was significantly lower, MD = -0.47 mmol/L (95% CI [-0.80, -0.15], p = .004). Significant improvements were also observed in cardiorespiratory fitness with exercise alone reducing resting heart rate, MD = -1.89 beats.min(-1) (95% CI [-2.90, -0.88], p = .0002), and peak VO2, MD = 4.86 ml.kg(-1).min(-1) (95% CI [2.83, 6.88], p < .00001). Lifestyle therapy also improved, peak VO2 MD = 5.09 ml.kg(-1).min(-1) (95% CI [3.13, 7.05], p < .00001). CONCLUSIONS Our analyses suggest lifestyle intervention is optimal for improving body composition and cardiorespiratory fitness in women with PCOS.

Effect of exercise training on liver function in adults who are overweight or exhibit fatty liver disease: a systematic review and meta-analysis

Objective Exercise training has been shown to have beneficial effects on liver function in adults overweight or with fatty liver disease. To establish which exercise programme characteristics were likely to elicit optimal improvements. Design Systematic review and meta-analysis of randomised, controlled trials. Data sources PubMed, CINAHL and Cochrane controlled trials registry searched (1966 to 2 October 2015). Eligibility criteria for selecting studies Exercise intervention, with or without dietary intervention, versus usual care in adults undertaking, exercise training, who were overweight, obese or exhibited fatty liver disease (non-alcoholic fatty liver disease or non-alcoholic steatohepatitis). Results We included 21 randomised controlled trials, totalling 1530 participants. Exercise intervention studies with total exercise programme workload >10 000 kcal produced significant improvements in intrahepatic fat, −3.46% (95% CI −5.20% to −1.73%), p<0.0001, I2=73%; effect size (standardised mean difference, SMD) −1.77 (−3.11 to −0.42), p=0.01, I2=77%. When data from only exercise studies were pooled, there was a reduction in fasting free fatty acids (FFAs) −74.15 µmol/L (95% CI −118.47 to −29.84), p=0.001, I2=67% with a large effect size (SMD) −0.94 (−1.36 to −0.52), p<0.0001, I2=0%. When data from only exercise studies were pooled, there was a significant reduction in insulin MD −1.88 UL (95% CI −3.43 to −0.34), p=0.02, I2=31%. The liver enzymes, alanine aminotransferase, aspartate aminotransferase and γ-glutamyl transpeptidase, were not significantly altered with exercise. Conclusions Exercise training reduces intrahepatic fat and FFAs while increasing cardiorespiratory fitness. An aggregate exercise programme energy expenditure (>10 000 kcal) may be required to promote reductions in intrahepatic fat.

The efficacy of isometric resistance training utilizing handgrip exercise for blood pressure management: A randomized trial.

Introduction:Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effective for assisting with blood pressure management. The aim of this study was to determine the efficacy of IRT for blood pressure management and the suitability of a low-intensity working control group. Methods:Forty hypertensive individuals, aged between 36 and 65 years, conducted IRT for 8 weeks. Participants were randomized into 2 groups, working at an intensity of either 5% or 30% of their maximum voluntary contraction. Participants performed 4 × 2 minute isometric handgrip exercises with their nondominant hand, each separated by a 3-minute rest period, 3 days a week. Results:Blood pressure measurements were conducted at baseline and at the end of the protocol using a Finometer. Eight weeks of isometric resistance training resulted in a 7-mmHg reduction of resting systolic blood pressure (SBP) (136 ± 12 to 129 ± 15; P = 0.04) in the 30% group. Reductions of 4 mmHg were also seen in mean arterial pressure (MAP) (100 ± 8 to 96 ± 11; P = 0.04) in the 30% group. There were no statistically significant reductions in diastolic blood pressure for the 30% group, or any of the data for the 5% group. Conclusion:Isometric resistance training conducted using handgrip exercise at 30% of maximum voluntary contraction significantly reduced SBP and MAP. A lack of reduction in blood pressure in the 5% group indicates that a low-intensity group may be suitable as a working control for future studies.