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Adipose tissue inflammation in breast cancer survivors: effects of a 16-week combined aerobic and resistance exercise training intervention.
Dieli-Conwright, CM, Parmentier, JH, Sami, N, Lee, K, Spicer, D, Mack, WJ, Sattler, F, Mittelman, SD
Breast cancer research and treatment. 2018;168(1):147-157
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Obese breast cancer patients have double the mortality compared to non-obese patients. This is thought to be mediated by low grade inflammation of the adipose (fat) tissue. The main type of immune cells involved in the process are called adipose tissue macrophages (ATMs), of which there are two types: M1 and M2 ATMs, with the M2 ATMs having a mostly anti-inflammatory effect, whilst the M1 ATMs are more pro-inflammatory and are thought to promote cancer growth and recurrence. This 16-week randomised pilot study assessed whether exercise can positively influence adipose tissue inflammation in breast cancer survivors. Participants were randomised to either an exercise (EX) group, who had three supervised exercise sessions per week with a combination of aerobic and resistance exercise, or a control (CON) group. Outcome measures included body composition, blood biomarkers for systemic inflammation and adipose tissue biopsies which were analysed for tissue inflammatory markers, including M1 and M2 ATMs. The EX group had significant improvements in body weight and composition, as well as in metabolic blood parameters (including those for lipid and glucose metabolism) and inflammatory markers, whilst the CON group experienced a worsening of these parameters. The EX participants also had a decrease in the pro-inflammatory M1 ATMs and an increase in the anti-inflammatory M2 ATMs. The authors state that the results were not only statistically, but also clinically significant. The authors conclude that moderate-to-vigorous intensity resistance and aerobic exercise can improve adipose tissue inflammation in obese breast cancer survivors.
Abstract
PURPOSE Obesity is a leading modifiable contributor to breast cancer mortality due to its association with increased recurrence and decreased overall survival rate. Obesity stimulates cancer progression through chronic, low-grade inflammation in white adipose tissue, leading to accumulation of adipose tissue macrophages (ATMs), in particular, the pro-inflammatory M1 phenotype macrophage. Exercise has been shown to reduce M1 ATMs and increase the more anti-inflammatory M2 ATMs in obese adults. The purpose of this study was to determine whether a 16-week exercise intervention would positively alter ATM phenotype in obese postmenopausal breast cancer survivors. METHODS Twenty obese postmenopausal breast cancer survivors were randomized to a 16-week aerobic and resistance exercise (EX) intervention or delayed intervention control (CON). The EX group participated in 16 weeks of supervised exercise sessions 3 times/week. Participants provided fasting blood, dual-energy X-ray absorptiometry (DXA), and superficial subcutaneous abdominal adipose tissue biopsies at baseline and following the 16-week study period. RESULTS EX participants experienced significant improvements in body composition, cardiometabolic biomarkers, and systemic inflammation (all p < 0.03 vs. CON). Adipose tissue from EX participants showed a significant decrease in ATM M1 (p < 0.001), an increase in ATM M2 (p < 0.001), increased adipose tissue secretion of anti-inflammatory cytokines such as adiponectin, and decreased secretion of the pro-inflammatory cytokines IL-6 and TNF- α (all p < 0.055). CONCLUSIONS A 16-week aerobic and resistance exercise intervention attenuates adipose tissue inflammation in obese postmenopausal breast cancer survivors. Future large randomized trials are warranted to investigate the impact of exercise-induced reductions in adipose tissue inflammation and breast cancer recurrence.
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The effect of a short-term low-carbohydrate, high-fat diet with or without postmeal walks on glycemic control and inflammation in type 2 diabetes: a randomized trial.
Myette-Côté, É, Durrer, C, Neudorf, H, Bammert, TD, Botezelli, JD, Johnson, JD, DeSouza, CA, Little, JP
American journal of physiology. Regulatory, integrative and comparative physiology. 2018;315(6):R1210-R1219
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Inflammation is associated with the pathogenesis of insulin resistance, type 2 diabetes (T2D), and related complications. Lifestyle therapy is a frontline treatment for improving glucose control in people with T2D. The main aim of this study was to determine whether reducing hyperglycaemia with a low-carbohydrate high-fat (LC) diet could lower markers of innate immune cell activation and systemic inflammation in people with T2D. A secondary aim was to examine if the combination of an LCHF diet with strategically timed postmeal walking was superior to an LCHF diet alone. The study is a randomised cross over study which enrolled Individuals with physician-diagnosed T2D to complete three short-term controlled-intervention periods. Sixteen participants were enrolled (men = 8 and women = 8) who were aged between 48 and 72 years. Results indicate that while LC and LC together with exercise (LC+Ex) led to superior improvements in glucose control and fasting proinsulin (the pro-hormone precursor to insulin) levels as compared with low-fat low glycaemic index diet (GL), all three diets (GL, LC and LC+Ex), appeared to lower a particular marker of cellular inflammation over the short-term. Authors conclude that an LCHF diet with or without daily postmeal walks improved four-day glycaemic control and fasting proinsulin levels compared with a GL diet.
Abstract
Lowering carbohydrate consumption effectively lowers glucose, but impacts on inflammation are unclear. The objectives of this study were to: 1) determine whether reducing hyperglycemia by following a low-carbohydrate, high-fat (LC) diet could lower markers of innate immune cell activation in type 2 diabetes (T2D) and 2) examine if the combination of an LC diet with strategically timed postmeal walking was superior to an LC diet alone. Participants with T2D ( n = 11) completed a randomized crossover study involving three 4-day diet interventions: 1) low-fat low-glycemic index (GL), 2) and 3) LC with 15-min postmeal walks (LC+Ex). Four-day mean glucose was significantly lower in the LC+Ex group as compared with LC (-5%, P < 0.05), whereas both LC+Ex (-16%, P < 0.001) and LC (-12%, P < 0.001) conditions were lower than GL. A significant main effect of time was observed for peripheral blood mononuclear cells phosphorylated c-Jun N-terminal kinase ( P < 0.001), with decreases in all three conditions (GL: -32%, LC: -45%, and LC+Ex: -44%). A significant condition by time interaction was observed for monocyte microparticles ( P = 0.040) with a significant decrease in GL (-76%, P = 0.035) and a tendency for a reduction in LC (-70%, P = 0.064), whereas there was no significant change in LC+Ex (0.5%, P = 0.990). Both LC (-27%, P = 0.001) and LC+Ex (-35%, P = 0.005) also led to significant reductions in circulating proinsulin. An LC diet improved 4-day glycemic control and fasting proinsulin levels when compared with GL, with added glucose-lowering benefits when LC was combined with postmeal walking.
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Carbohydrate restriction with postmeal walking effectively mitigates postprandial hyperglycemia and improves endothelial function in type 2 diabetes.
Francois, ME, Myette-Cote, E, Bammert, TD, Durrer, C, Neudorf, H, DeSouza, CA, Little, JP
American journal of physiology. Heart and circulatory physiology. 2018;314(1):H105-H113
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Prevention of cardiovascular disease in individuals with type 2 diabetes (T2D) is a major treatment goal. Within this, diet and exercise remain the cornerstone lifestyle therapies. The aim of this study was to examine the effects of 4 days of a low-carbohydrate diet, with or without daily post-meal walking, on vascular health in individuals with T2D. The study recruited sixteen individuals with physician-diagnosed T2D to complete 3 short-term controlled intervention periods in a randomised crossover design. Results indicate that attenuating postprandial hyperglycaemia (a very high rise in blood sugar following a meal) by restricting carbohydrates and post-meal walking can improve vascular health in individuals with T2D. Authors conclude that carbohydrate restriction and post-meal exercise may represent an effective strategy to mitigate the negative effects of postprandial hyperglycaemia and reduce cardiovascular disease risk in individuals with T2D.
Abstract
Postprandial hyperglycemia has deleterious effects on endothelial function. Restricting carbohydrate intake and postmeal walking have each been shown to reduce postprandial hyperglycemia, but their combination and subsequent effects on endothelial function have not been investigated. Here, we sought to examine the effect of blunting postprandial hyperglycemia by following a low-carbohydrate diet, with or without postmeal walking exercise, on markers of vascular health in type 2 diabetes (T2D). In a randomized crossover design, individuals with T2D ( n = 11) completed three 4-day controlled diet interventions consisting of 1) low-carbohydrate diet alone (LC), 2) low-carbohydrate diet with 15-min postmeal walks (LC + Ex), and 3) low-fat control diet (CON). Fasting blood samples and brachial artery flow-mediated dilation (%FMD) were measured before and after each intervention. Total circulating microparticles (MPs), endothelial MPs, platelet MPs, monocyte-platelet aggregates, and adhesion molecules were assessed as biomarkers of vascular health. There was a significant condition × time interaction for %FMD ( P = 0.01), with post hoc tests revealing improved %FMD after LC + Ex (+0.8 ± 1.0%, P = 0.02), with no change after LC or CON. Endothelial MPs were significantly reduced with the LC diet by ~45% (from 99 ± 60 to 44 ± 31 MPs/μl, P = 0.02), with no change after LC + Ex or CON (interaction: P = 0.04). Total MPs were lower (main effect time: P = 0.02), whereas monocyte-platelet aggregates were higher (main effect time: P < 0.01) after all interventions. Plasma adhesion molecules and C-reactive protein were unaltered. Attenuating postprandial hyperglycemic excursions using a low-carbohydrate diet combined with postmeal walking appears to be an effective strategy to improve endothelial function in individuals with T2D. NEW & NOTEWORTHY Carbohydrate restriction and postmeal walking lower postprandial hyperglycemia in individuals with type 2 diabetes. Here, we show that the combination significantly improved endothelial function and that carbohydrate restriction alone reduced circulating endothelial microparticles in individuals with type 2 diabetes. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/low-carb-diet-and-exercise-improve-endothelial-health/ .
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Exercise Preserves Physical Function in Prostate Cancer Patients with Bone Metastases.
Galvão, DA, Taaffe, DR, Spry, N, Cormie, P, Joseph, D, Chambers, SK, Chee, R, Peddle-McIntyre, CJ, Hart, NH, Baumann, FT, et al
Medicine and science in sports and exercise. 2018;50(3):393-399
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Existing research indicates cancer patients with bone metastases should not participate in exercise due to potential risks to the skeletal system. However, current oncology guidelines suggest that all cancer patients should avoid inactivity, including those with bone metastases. The purpose of this study is to determine the safety and efficacy of exercise among 57 prostate cancer patients with bone metastases. Participants were randomised to either participate in exercise or receive usual care for three months. Exercise consisted of supervised aerobic activity, resistance training and stretching three days a week. Overall health status and physical function was measured by self-reported questionnaire. This study found self-reported physical functioning and lower muscle strength was improved significantly in the exercise group. There were no difference in bone pain between groups, and no adverse events occurred. Based on these results, the authors conclude exercise is safe and can help improve physical functioning among prostate cancer patients with bone metastasis.
Abstract
PURPOSE The presence of bone metastases has excluded participation of cancer patients in exercise interventions and is a relative contraindication to supervised exercise in the community setting because of concerns of fragility fracture. We examined the efficacy and safety of a modular multimodal exercise program in prostate cancer patients with bone metastases. METHODS Between 2012 and 2015, 57 prostate cancer patients (70.0 ± 8.4 yr; body mass index, 28.7 ± 4.0 kg·m) with bone metastases (pelvis, 75.4%; femur, 40.4%; rib/thoracic spine, 66.7%; lumbar spine, 43.9%; humerus, 24.6%; other sites, 70.2%) were randomized to multimodal supervised aerobic, resistance, and flexibility exercises undertaken thrice weekly (EX; n = 28) or usual care (CON; n = 29) for 3 months. Physical function subscale of the Medical Outcomes Study Short-Form 36 was the primary end point as an indicator of patient-rated physical functioning. Secondary end points included objective measures of physical function, lower body muscle strength, body composition, and fatigue. Safety was assessed by recording the incidence and severity of any adverse events, skeletal complications, and bone pain throughout the intervention. RESULTS There was a significant difference between groups for self-reported physical functioning (3.2 points; 95% confidence interval, 0.4-6.0 points; P = 0.028) and lower body muscle strength (6.6 kg; 95% confidence interval, 0.6-12.7; P = 0.033) at 3 months favoring EX. However, there was no difference between groups for lean mass (P = 0.584), fat mass (P = 0.598), or fatigue (P = 0.964). There were no exercise-related adverse events or skeletal fractures and no differences in bone pain between EX and CON (P = 0.507). CONCLUSIONS Multimodal modular exercise in prostate cancer patients with bone metastases led to self-reported improvements in physical function and objectively measured lower body muscle strength with no skeletal complications or increased bone pain. TRIAL REGISTRATION ACTRN12611001158954.
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Health Effects of 12 Weeks of Team-Sport Training and Fitness Training in a Community Health Centre for Sedentary Men with Lifestyle Diseases.
Møller, TK, Nielsen, TT, Andersen, R, Lundager, I, Hansen, HF, Ottesen, L, Krustrup, P, Randers, MB
BioMed research international. 2018;2018:1571807
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Physical activity helps to prevent and manage chronic disease, particularly in the aging population. Existing research shows physical activity programmes improve physical capacity and body composition, however participants report difficulty maintaining their training habits once the intervention is finished. The aim of this study was to produce a pragmatic, real-life setup to compare the health effects of team-sport activities with traditional fitness training among men with lifestyle disease in the community health centre context. This study took place over two years. During the first year, 32 men participated in the traditional fitness training to obtain baseline effects. For the second year, all training sessions were replaced with team-sport training and 36 men participated. This study found that team-sport activities produced comparable effects on various health parameters to the traditional fitness-training programme. Based on these results, the authors conclude that team sport activities are a worthy alternative to fitness training in community health centres.
Abstract
This study compares the effects of team-sport training, for sedentary men with lifestyle diseases, with fitness training in a pragmatic set-up in a community health centre (CHC). Thirty-two men in the fitness group (FiG) and 36 men in the team-sport group (TsG) completed the training and trained for 60-90 min, two times/week for 12-16 weeks. In FiG and TsG, mean heart rate (HR) during training was 73.2% and 74.5% of HRmax, respectively. Percentage of training time above 90%HRmax was 6 ± 9% and 10 ± 15% and the percentage of participants who spent > 10% of total training time with HR > 90%HRmax was 20% and 41%, in FiG and TsG, respectively. In FiG, total fat mass was reduced by 3.5% (P < 0.01), while performance in the 6 min walking test (6MWT) increased by 11% (P < 0.001). In TsG, total fat mass was reduced by 2.2% (P < 0.01), while 6MWT performance improved by 5% (P < 0.05). Between-group differences were observed for systolic BP (P = 0.041) and mean arterial pressure (P = 0.050) in favour of TsG and for sit-to-stand test (P = 0.031) in favour of FiG. In conclusion, small-sided team sport is a worthy alternative to fitness training since the overall health effects are comparable, for example, improved balance and reduced fat mass. Team sport elicits high heart rates and improves cardiovascular health by reducing blood pressure, while fitness training improves sit-to-stand test performance related to activity of daily living.
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Combination of Exercise and Acupuncture Versus Acupuncture Alone for Treatment of Myofascial Pain Syndrome: A Randomized Clinical Trial.
Eftekharsadat, B, Porjafar, E, Eslamian, F, Shakouri, SK, Fadavi, HR, Raeissadat, SA, Babaei-Ghazani, A
Journal of acupuncture and meridian studies. 2018;11(5):315-322
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Myofascial pain syndrome (MPS) is a chronic condition in which connective tissue is inflamed and trigger points along muscle bands are hyper-sensitive. Previous studies have demonstrated that both exercise and acupuncture are effective for managing MPS. The purpose of this study was to investigate whether physical activity produced an additive effect in 64 patients receiving acupuncture for MPS. Participants were randomised to receive ten sessions of acupuncture or physical activity in addition to acupuncture. Pain measurements and quality of life questionnaires were completed and assessed. This single blind randomised study found that both exercise and acupuncture led to similar reductions in pain. Contrary to the hypothesis, there was no significant difference between the two groups, suggesting physical activity did not produce additive beneficial effect. Based on these results, the authors conclude both exercise combined with acupuncture or acupuncture alone are effective in managing MPS.
Abstract
Myofascial pain syndrome (MPS) is a common musculoskeletal disorder. This study was designed to compare the effects of aerobic exercise plus acupuncture with acupuncture alone in treatment of patients with MPS. Sixty-four patients (55 female and 9 male) with MPS in their neck and shoulders participated in the study with mean age of 33.1 ± 6.4 years. Participants were randomly allocated to aerobic exercise plus acupuncture (n = 32) or acupuncture alone (n = 32) groups. Outcome measurements included visual analog scale, pressure pain threshold, neck disability index, and quality of life that was measured with QoL-SF36 scale. Each group received 10 sessions of acupuncture in combination with aerobic exercise or acupuncture alone. The outcome measures were evaluated at baseline, at the end of the last treatment session, and at 1-month follow-up visit. While participants were waiting for their 1-month follow-up visit, the patients who received combination therapy were asked to continue their aerobic exercise by jogging 40 minutes a day. Although mean visual analog scale, pressure pain threshold, neck disability index, and QoL-SF36 were significantly improved in both groups (p < 0.001), there was no statistically significant difference among the measures between the two groups throughout the evaluated sessions. The interaction effect of time and groups did not show any significant difference among the outcome measures (p > 0.29).
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Inflammation and glucose homeostasis are associated with specific structural features among adults without knee osteoarthritis: a cross-sectional study from the osteoarthritis initiative.
Stout, AC, Barbe, MF, Eaton, CB, Amin, M, Al-Eid, F, Price, LL, Lu, B, Lo, GH, Zhang, M, Pang, J, et al
BMC musculoskeletal disorders. 2018;19(1):1
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Individuals with osteoarthritis (OA) typically present with greater systemic inflammation and impaired glucose homeostasis. Currently it is unclear whether these factors are associated with early-stage OA, namely bone marrow lesions and swelling. The purpose of this cross-sectional study was to investigate the role of inflammation and glucose homeostasis in early-stage OA. Using baseline data from the Osteoarthritis Initiative, 343 participants were enrolled and tested for markers of inflammation and impaired glucose homeostasis. Bone marrow lesions and swelling were also assessed through imaging results. Results indicate that among individuals without OA, those with greater systemic inflammation were more likely to have bone marrow lesions and knee swelling. According to these results, the authors conclude that systemic inflammation and glucose homeostasis are related to structural features of osteoarthritis. Future studies should explore whether these factors are predictive of OA in order to identify therapeutic targets to prevent or delay the onset of knee OA.
Abstract
BACKGROUND Greater age and body mass index are strong risk factors for osteoarthritis (OA). Older and overweight individuals may be more susceptible to OA because these factors alter tissue turnover in menisci, articular cartilage, and bone via altered glucose homeostasis and inflammation. Understanding the role of inflammation and glucose homeostasis on structural features of early-stage OA may help identify therapeutic targets to delay or prevent the onset of OA among subsets of adults with these features. We examined if serum concentrations of glucose homeostasis (glucose, glycated serum protein [GSP]) or inflammation (C-reactive protein [CRP]) were associated with prevalent knee bone marrow lesions (BMLs) or effusion among adults without knee OA. METHODS We conducted a cross-sectional study using baseline data from the Osteoarthritis Initiative. We selected participants who had no radiographic knee OA but were at high risk for knee OA. Blinded staff conducted assays for CRP, GSP, and glucose. Readers segmented BML volume and effusion using semi-automated programs. Our outcomes were prevalent BML (knee with a BML volume > 1 cm3) and effusion (knee with an effusion volume > 7.5 cm3). We used logistic regression models with CRP, GSP, or glucose concentrations as the predictors. We adjusted for age, sex, body mass index (BMI), and Physical Activity Scale for the Elderly (PASE) scores. RESULTS We included 343 participants: mean age = 59 ± 9 years, BMI = 27.9 ± 4.5 kg/m2, PASE score = 171 ± 82, and 64% female. Only CRP was associated with BML prevalence (odds ratio [OR] = 1.43, 95% confidence interval [CI] = 1.09 to 1.87). For effusion, we found an interaction between BMI and CRP: only among adults with a BMI <25 kg/m2 was there a significant trend towards a positive association between CRP and effusion (OR = 1.40, 95% CI = 1.00 to 1.97). We detected a U-shaped relationship between GSP and effusion prevalence. Fasting glucose levels were not significantly associated with the presence of baseline effusion or BML. CONCLUSIONS Among individuals without knee OA, CRP may be related to the presence of BMLs and effusion among normal weight individuals. Abnormal GSP may be associated with effusion. Future studies should explore whether inflammation and glucose homeostasis are predictive of symptomatic knee OA.
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A low-dose, 6-week bovine colostrum supplementation maintains performance and attenuates inflammatory indices following a Loughborough Intermittent Shuttle Test in soccer players.
Kotsis, Y, Mikellidi, A, Aresti, C, Persia, E, Sotiropoulos, A, Panagiotakos, DB, Antonopoulou, S, Nomikos, T
European journal of nutrition. 2018;57(3):1181-1195
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In elite athletes, recovery time between matches is often suboptimal. Since exercise-induced muscle damage (EIMD) can determine the duration of the recovery period, several strategies have been explored to reduce recovery time by attenuating EIMD. The aim of this placebo-controlled, double-blind randomised trial was to examine the effect of a long-term, low-dose bovine colostrum (BC) supplementation on EIMD and performance in 18 elite soccer players. To set a baseline, all participants completed the Loughborough Intermittent Shuttle Test (LIST), a fitness test that simulates the activity pattern of a soccer match, and muscle damage indices were monitored for 72 hours post-exercise. Subjects were then randomised to consume either BC or whey as placebo daily for 6 weeks, and complete the LIST post-intervention with the same indices monitored. This study found that BC helped maintain performance and attenuate post-exercise inflammatory markers compared to whey. Based on these results, the authors conclude a low-dose of BC may reduce post-exercise EIMD and help enhance muscle recovery during a soccer match.
Abstract
PURPOSE The aim of the study was to investigate the effect of a 6-week, low-dose bovine colostrum (BC) supplementation on exercise-induced muscle damage (EIMD) and performance decline in soccer players following the Loughborough Intermittent Shuttle Test (LIST) during a competitive season period. METHODS In a double-blind, randomized, placebo-controlled design, two groups of soccer players were allocated to a 3.2 g/day of whey protein (WP, N = 8) or BC (N = 10) and performed a pre- and a post-supplementation LIST. Maximum isometric voluntary contraction, squat jump (SQJ), countermovement jump, muscle soreness, blood cell counts, creatine kinase (CK), C-reactive protein (CRP) and interleukin-6 (IL-6) were monitored for 2, 24, 48, 72 h post-LIST. RESULTS LIST induced transient increases in leukocytes, granulocytes, CK, muscle soreness, CRP, IL-6 and declines in lymphocytes and performance indices. Supplementation resulted in a faster recovery of SQJ, CK and CRP compared to pre-supplementation kinetics (trial × time: p = 0.001, 0.056, 0.014, respectively) and lower incremental area under the curve (iAUC) for IL-6, only in the BC group [pre-: 31.1 (6.78-46.9), post-: 14.0 (-0.16 to 23.5) pg h/ml, p = 0.034]. Direct comparison of the two groups after supplementation demonstrated higher iAUC of SQJ [WP: -195.2 (-229.0 to (-52.5)), BC: -15.8 (-93.2 to 16.8) cm h, p = 0.034], a trend for lower iAUC of CK in the BC group [WP: 18,785 (4651-41,357), BC: 8842 (4807-14,802) U h/L, p = 0.081] and a significant intervention × time interaction for CRP (p = 0.038) in favor of BC. CONCLUSIONS Post-exercise EIMD may be reduced and performance better maintained by a low dose of BC administration following LIST in soccer players.
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Dietary nitrate does not modify blood pressure and cardiac output at rest and during exercise in older adults: a randomised cross-over study.
Oggioni, C, Jakovljevic, DG, Klonizakis, M, Ashor, AW, Ruddock, A, Ranchordas, M, Williams, E, Siervo, M
International journal of food sciences and nutrition. 2018;69(1):74-83
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Nitrates are naturally-occurring compounds that are produced within the body and also found in food. The main sources of nitrates in the diet come from cured meats and vegetables such as spinach, rocket and beetroot. Nitrate supplements have been associated with beneficial effects on heart and metabolic health, and improvements in athletic performance. Many of these benefits have been observed in younger adults. The objective of this randomised controlled trial was to investigate the effects of 7 days’ consumption of beetroot juice compared with placebo on (1) blood pressure (BP) measured in resting conditions and during exercise, (2) cardiac and peripheral vascular function and (3) biomarkers of inflammation, oxidative stress and endothelial integrity, in older adults. Twenty non-smoking healthy participants aged 60-75 years were recruited. Each participant was given 70ml of either beetroot juice rich in nitrates, or beetroot juice low in nitrates (placebo), twice a day for 7 days. All participants took both the 7-day courses, with at least 7 days rest in between. Measurement was conducted before and after each 7-day intervention period. Consumption of nitrates had no effect on resting systolic and diastolic BP. Nitrate consumption did not improve heart function during exercise. Nitrate consumption did not change markers of inflammation, oxidative stress and endothelial integrity. The authors concluded that this study does not support the short-term benefits of dietary nitrate supplementation on physiological and biochemical markers of heart health in older healthy adults.
Abstract
Dietary nitrate (NO3-) supplementation has been associated with improved vascular and metabolic health. We conducted a double-blind, cross-over, placebo-controlled RCT to investigate the effects of 7-d consumption of beetroot juice compared with placebo on (1) blood pressure (BP) measured in resting conditions and during exercise, (2) cardiac and peripheral vascular function and (3) biomarkers of inflammation, oxidative stress and endothelial integrity. Twenty non-smoking healthy participants aged 60-75 years and BMI 20.0-29.9 kg/m2 were recruited. Measurement was conducted before and after each 7-d intervention period. Consumption of NO3- had no effect on resting systolic and diastolic BP. NO3- consumption did not improve indexes of central and peripheral cardiac function responses during cardiopulmonary exercise testing. Dietary NO3- supplementation did not modify biomarkers of inflammation, oxidative stress and endothelial integrity. This study does not support the short-term benefits of dietary NO3- supplementation on physiological and biochemical markers of vascular health in older healthy adults.
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Effects of β-alanine supplementation during a 5-week strength training program: a randomized, controlled study.
Maté-Muñoz, JL, Lougedo, JH, Garnacho-Castaño, MV, Veiga-Herreros, P, Lozano-Estevan, MDC, García-Fernández, P, de Jesús, F, Guodemar-Pérez, J, San Juan, AF, Domínguez, R
Journal of the International Society of Sports Nutrition. 2018;15:19
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β-alanine (BA) is a non-essential amino acid and has been shown to improve athletic performance during short, high-intensity exercises. While BA has been tested in overall sports performance, few studies have examined the specific effect of BA in resistance training. The aim of this trial was to observe the impact of BA supplementation during a resistance-training programme in 26 weight-trained athletes. Participants were randomised to receive daily BA or placebo supplementation for five weeks, training three times per week. An incremental load test was performed before and after the training programme. This study found BA consumption significantly improved power output, weight lifted, number of sets executed compared with placebo. Based on these results, the authors conclude the ergogenic effect of BA supplementation on power generation were the result of an increased workload.
Abstract
BACKGROUND β-Alanine (BA) is a non-essential amino acid that has been shown to enhance exercise performance. The purpose of this investigation was to determine if BA supplementation improved the adaptive response to five weeks of a resistance training program. METHODS Thirty healthy, strength-trained individuals were randomly assigned to the experimental groups placebo (PLA) or BA. Over 5 weeks of strength training, subjects in BA took 6.4 g/day of BA as 8 × 800 mg doses each at least 1.5 h apart. The training program consisted of 3 sessions per week in which three different leg exercises were conducted as a circuit (back squat, barbell step ups and loaded jumping lunges). The program started with 3 sets of 40 s of work per exercise and rest periods between sets of 120 s in the first week. This training volume was then gradually built up to 5 sets of 20 s work/60 s rest in the fifth week. The work load during the program was set by one of the authors according to the individual's perceived effort the previous week. The variables measured were average velocity, peak velocity, average power, peak power, and load in kg in a back squat, incremental load, one-repetition maximum (1RM) test. In addition, during the rest period, jump ability (jump height and power) was assessed on a force platform. To compare data, a general linear model with repeated measures two-way analysis of variance was used. RESULTS Significantly greater training improvements were observed in the BA group versus PLA group (p = 0.045) in the variables average power at 1RM (BA: 42.65%, 95% CI, 432.33, 522.52 VS. PLA: 21.07%, 95% CI, 384.77, 482.19) and average power at maximum power output (p = 0.037) (BA: 20.17%, 95% CI, 637.82, 751.90 VS. PLA; 10.74%, 95% CI, 628.31, 751.53). The pre- to post training average power gain produced at 1RM in BA could be explained by a greater maximal strength gain, or load lifted at 1RM (p = 0.014) (24 kg, 95% CI, 19.45, 28.41 VS. 16 kg, 95% CI, 10.58, 20.25) and in the number of sets executed (p = 0.025) in the incremental load test (BA: 2.79 sets, 95% CI, 2.08, 3.49 VS. PLA: 1.58 sets, 95% CI, 0.82, 2.34). CONCLUSIONS β-Alanine supplementation was effective at increasing power output when lifting loads equivalent to the individual's maximal strength or when working at maximum power output. The improvement observed at 1RM was explained by a greater load lifted, or strength gain, in response to training in the participants who took this supplement.