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The Dose-Effects of Caffeine on Lower Body Maximal Strength, Muscular Endurance, and Rating of Perceived Exertion in Strength-Trained Females.
Jones, L, Johnstone, I, Day, C, Le Marquer, S, Hulton, AT
Nutrients. 2021;13(10)
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Caffeine is a common ingredient in tea, coffee, chocolate, soft drinks and multi-ingredient pre-workout supplements. It is believed to elicit an ergogenic effect that enhances athletic performance. However, only very few studies have examined the effect of caffeine on women who take contraceptive pills. The aim of this double-blind, randomised, counterbalanced, crossover trial was to investigate the ergogenic effect of pre-exercise caffeine supplementation on strength performance and muscular endurance in strength-trained females taking contraceptives. Fourteen women were randomised to consume doses of 3 and 6 mg·kg−1 body mass of caffeine supplement or placebo thirty minutes prior to the exercise. Caffeine supplementation at 3 and 6 mg·kg−1 body mass significantly improved muscular endurance and total strength. No significant difference was observed between the higher and lower doses of caffeine in improving performance, indicating that the lower dose can potentially provide the same benefit without the adverse effect of the higher dose. The low dose had a similar caffeine content to that of a large coffee latte from a coffee shop, suggesting beneficial effects could be achieved through coffee/latte consumption. Caution should be applied when extrapolating the findings for eumenorrheic females with different training statuses. Healthcare practitioners can, however, use the results of this study to understand the potential benefits of caffeine for strength-trained women using hormone contraception.
Abstract
Caffeine supplementation has shown to be an effective ergogenic aid enhancing athletic performance, although limited research within female populations exists. Therefore, the aim of the investigation was to assess the effect of pre-exercise caffeine supplementation on strength performance and muscular endurance in strength-trained females. In a double-blind, randomised, counterbalanced design, fourteen strength-trained females using hormonal contraception consumed either 3 or 6 mg·kg-1 BM of caffeine or placebo (PLA). Following supplementation, participants performed a one-repetition maximum (1RM) leg press and repetitions to failure (RF) at 60% of their 1RM. During the RF test, rating of perceived exertion (RPE) was recorded every five repetitions and total volume (TV) lifted was calculated. Repeated measures ANOVA revealed that RF (p = 0.010) and TV (p = 0.012) attained significance, with pairwise comparisons indicating a significant difference between 3 mg·kg-1 BM and placebo for RF (p = 0.014), with an effect size of 0.56, and for 6 mg·kg-1 BM (p = 0.036) compared to the placebo, with an effect size of 0.65. No further significance was observed for 1RM or for RPE, and no difference was observed between caffeine trials. Although no impact on lower body muscular strength was observed, doses of 3 and 6 mg·kg-1 BM of caffeine improved lower body muscular endurance in resistance-trained females, which may have a practical application for enhancing resistance training stimuli and improving competitive performance.
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Lifestyle factors and visceral adipose tissue: Results from the PREDIMED-PLUS study.
Galmes-Panades, AM, Konieczna, J, Abete, I, Colom, A, Rosique-Esteban, N, Zulet, MA, Vázquez, Z, Estruch, R, Vidal, J, Toledo, E, et al
PloS one. 2019;14(1):e0210726
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Excess visceral adipose tissue (VAT, abdominal fat) is a risk factor for developing cardiovascular disease, type 2 diabetes mellitus and all cause mortality. Lifestyle factors, including diet and physical activity, are associated with VAT. This cross-sectional study evaluated the association between different levels of physical activity (PA), adherence to an energy-restricted Mediterranean diet and sedentary lifestyle with VAT in older people with overweight/obesity and metabolic syndrome. Data were taken from an ongoing randomised study evaluating the effect of a weight loss programme based on an energy-restricted Mediterranean diet, promotion of physical activity and behavioural support compared to usual care consisting of advice on an energy-unrestricted Mediterranean diet only. Total and moderate-to-vigorous physical activity and muscle strength were inversely, and sedentary behaviour was positively associated with VAT. There was no statistically significant association between VAT and light exercise, adherence to the energy-reduced Mediterranean diet and watching TV.
Abstract
BACKGROUND Visceral adipose tissue (VAT) is a strong predictor of cardiometabolic health, and lifestyle factors may have a positive influence on VAT depot. This study aimed to assess the cross-sectional associations between baseline levels of physical activity (PA), sedentary behaviours (SB) and adherence to the Mediterranean diet (MedDiet) with VAT depot in older individuals with overweight/obesity and metabolic syndrome. METHODS Baseline data of the PREDIMED-Plus study including a sample of 1,231 Caucasian men and women aged 55-75 years were used. Levels of leisure-time PA (total, light, and moderate-to-vigorous, in METs·min/day) and SB (total and TV-viewing, in h/day) were evaluated using validated questionnaires. Adherence to the MedDiet was evaluated using a 17-item energy-restricted MedDiet (erMedDiet) screener. The chair-stand test was used to estimate the muscle strength. VAT depot was assessed with DXA-CoreScan. Multivariable adjusted linear regression models were used to evaluate the association between lifestyle factors and VAT. For the statistics we had used multiadjusted linear regression models. RESULTS Total leisure-time PA (100 METs·min/day: β -24.3g, -36.7;-11.9g), moderate-to-vigorous PA (β -27.8g, 95% CI -40.8;-14.8g), chair-stand test (repeat: β -11.5g, 95% CI -20.1;-2.93g) were inversely associated, and total SB (h/day: β 38.2g, 95% CI 14.7;61.7) positively associated with VAT. Light PA, TV-viewing time and adherence to an erMedDiet were not significantly associated with VAT. CONCLUSIONS In older adults with overweigh/obesity and metabolic syndrome, greater PA, muscle strength, and lower total SB were associated with less VAT depot. In this study, adherence to an erMedDiet was not associated with lower VAT.
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A 12-Month Lifestyle Intervention Program Improves Body Composition and Reduces the Prevalence of Prediabetes in Obese Patients.
König, D, Hörmann, J, Predel, HG, Berg, A
Obesity facts. 2018;11(5):393-399
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Obesity and its impact on the prevalence of diabetes and subsequent cardiovascular disease is one of the major health burdens in Western societies. Lifestyle intervention studies have shown that weight loss combined with increased physical activity can improve metabolic risk factors. The aim of this study was to evaluate the effect of a comprehensive lifestyle intervention programme on weight and metabolic risk factors in 5884 obese individuals. The programme included 61 sessions over 12 months, including 41 exercise sessions, 12 psychological/self-management sessions and 8 nutritional counselling sessions (based on a low glycaemic index, low fat diet). After 12 months there was a significant reduction in weight (average 6%), waist circumference, physical fitness and all metabolic parameters (including blood sugar and fat metabolism). Overall, in 839 (38%) of the 2,227 participants who were pre-diabetic before intervention, the criteria of pre-diabetes were no longer detectable after 12 months, whilst only 66 (3%) progressed to type 2 diabetes mellitus. 46.7% of the 1,641 participants fulfilling the criteria of metabolic syndrome before the intervention, did not show any signs of this syndrome after the intervention; whilst only 120 participants (+7.3%) newly developed metabolic syndrome. The authors concluded that the intensive lifestyle intervention programme was successful, even in obese people with pre-diabetes.
Abstract
BACKGROUND The present study investigated the effects of a 12-month interdisciplinary standardized lifestyle program addressing physical activity and changes in dietary and lifestyle behavior in 2,227 obese prediabetic participants. METHODS Measures of obesity (BMI, waist circumference), cardiopulmonary fitness, and metabolic parameters were determined before and after the intervention period. RESULTS From the 2,227 participants who were initially prediabetic, 839 participants (-37.7%) did no longer show the criteria of prediabetes after the intervention and had normal HbA1c levels. CONCLUSION The clinical effects are substantial, and it is likely that the applied intense and multidisciplinary lifestyle interventions could reduce the risk of developing diabetes and the prevalence of a full-blown metabolic syndrome in obese and prediabetic patients.
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Regaining body weight after weight reduction further increases pulse wave velocity in obese men with metabolic syndrome.
Liang, KW, Lee, WJ, Lee, IT, Lin, SY, Wang, JS, Lee, WL, Sheu, WH
Medicine. 2018;97(40):e12730
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Atherosclerosis can increase stiffness of the aorta and, therefore, increased pulse wave velocity (PWV), which is a predictor for cardiovascular disease and mortality. Metabolic syndrome (MetS), diabetes and obesity increase the risk of aortic stiffness and higher PWV. Weight loss may reduce arterial stiffness but mechanisms are not known. The aim this study was to investigate changes over time of PWV, ankle-brachial index (ABI, a marker for arterial disease of the leg), insulin resistance and inflammatory markers after weight loss and regained weight in obese non-diabetic men with MetS compared to lean controls. Obese participants followed a three months weight loss programme based on diet and exercise during which they lost an average of 8.6kg and saw statistically significant improvements in blood pressure and many biochemical markers but not in PWV or ABI. At the second follow-up visit, at 60 months, they had regained their weight, blood pressure and most biochemical markers were back to baseline whilst PWV and adiponectin were worse than before weight loss. Increases in blood pressure but not weight, hs-CRP (an inflammatory marker) or insulin resistance correlated with the increase in PWV after weight regain. Although healthy controls also gained weight over the 60 months study duration, their increase in PWV was significantly lower than in obese participants. Their PWV was also lower at baseline.
Abstract
Subjects with metabolic syndrome (MetS) or obesity have worse arterial stiffness. However, there have been no studies addressing time-sequential changes in pulse wave velocity (PWV) after weight loss and then regaining weight in obese non-diabetic men with MetS.We prospectively enrolled 40 obese, non-diabetic men with MetS undergoing a 3-month weight reduction program. Another 26 lean and healthy men were recruited for comparisons. Oral glucose tolerance test and brachial ankle (ba) PWV were assessed in study subjects. Eighteen obese non-diabetic MetS and 15 lean control subjects had follow-ups at the 60th month.The body weight of obese MetS decreased from 94.8 ± 7.6 to 86.1 ± 9.0 (N = 18, P < .001) after a 3-month weight reduction program but regained gradually thereafter to 93.6 ± 11.6 kg at the 60th month (P < .001 versus 3rd month). baPWV decreased after weight loss slightly (P = .240) while weight regain significantly increased the baPWV (from 3rd month, 1358 ± 168 to 60th month 1539 ± 264 cm/sec, P < .001). Systolic and diastolic blood pressure increments correlated with the increment of baPWV after weight regain. At the 60th month, lean controls (N = 15) had increases in body weight while their baPWV increased non-significantly. The increments of baPWV after weight regain in obese MetS were significantly higher than the increment of baPWV in lean controls after weight gain.In conclusion, regaining body weight after weight reduction worsened arterial stiffness with significant increase of baPWV in obese non-diabetic MetS.
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Timed-daily ingestion of whey protein and exercise training reduces visceral adipose tissue mass and improves insulin resistance: the PRISE study.
Arciero, PJ, Baur, D, Connelly, S, Ormsbee, MJ
Journal of applied physiology (Bethesda, Md. : 1985). 2014;117(1):1-10
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High-protein diets may promote weight loss and improved body composition via a number of mechanisms such as increasing satiety and promoting muscle synthesis. The aim of this study was to examine the effects of timed ingestion of whey protein on body weight, fat distribution, insulin resistance and hunger. A secondary aim was to assess the effect of different exercise regimes on the same outcomes. Participants were sedentary and overweight or obese, but otherwise healthy, adults. For 16 weeks, all participants consumed three 20g servings of whey protein per day; within 1 hour of waking, mid-afternoon or within 30 minutes of exercise, and within 2 hours of going to bed (P). Some participants were also assigned to an exercise regime consisting of either resistance and sprint training (RT) or a mixed regime of resistance training, interval training, stretching and endurance (RISE). All participants continued to consume their usual diets. All three groups saw improvements in markers of their body composition and cardiometabolic health, regardless of whether they exercised or not. However, the combined effects of whey protein and exercise resulted in additional improvements in visceral fat, adipokines and insulin sensitivity. Whey protein plus the mixed exercise regime (RISE) was associated with the greatest improvements and the authors concluded that this is an effective lifestyle intervention for overweight and obese adults.
Abstract
The present study examined the effects of timed ingestion of supplemental protein (20-g servings of whey protein, 3×/day), added to the habitual diet of free-living overweight/obese adults and subsequently randomized to either whey protein only (P; n = 24), whey protein and resistance exercise (P + RT; n = 27), or a whey protein and multimode exercise training program [protein and resistance exercise, intervals, stretching/yoga/Pilates, endurance exercise (PRISE); n = 28]. Total and regional body composition and visceral adipose tissue (VAT) mass (dual-energy X-ray absorptiometry), insulin sensitivity [homeostasis model assessment-estimated insulin resistance (HOMA-IR)], plasma lipids and adipokines, and feelings of hunger and satiety (visual analog scales) were measured before and after the 16-wk intervention. All groups lost body weight, fat mass (FM), and abdominal fat; however, PRISE lost significantly (P < 0.01) more body weight (3.3 ± 0.7 vs. 1.1 ± 0.7 kg, P + RT) and FM (2.8 ± 0.7 vs. 0.9 ± 0.5 kg, P + RT) and gained (P < 0.05) a greater percentage of lean body mass (2 ± 0.5 vs. 0.9 ± 0.3 and 0.6 ± 0.4%, P + RT and P, respectively). Only P + RT (0.1 ± 0.04 kg) and PRISE (0.21 ± 0.07 kg) lost VAT mass (P < 0.05). Fasting glucose decreased only in P + RT (5.1 ± 2.5 mg/dl) and PRISE (15.3 ± 2.1 mg/dl), with the greatest decline occurring in PRISE (P < 0.05). Similarly, HOMA-IR improved (0.6 ± 0.3, 0.6 ± 0.4 units), and leptin decreased (4.7 ± 2.2, 4.7 ± 3.1 ng/dl), and adiponectin increased (3.8 ± 1.1, 2.4 ± 1.1 μg/ml) only in P + RT and PRISE, respectively, with no change in P. In conclusion, we find evidence to support exercise training and timed ingestion of whey protein added to the habitual diet of free-living overweight/obese adults, independent of caloric restriction on total and regional body fat distribution, insulin resistance, and adipokines.
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Physiologic and behavioral indicators of energy deficiency in female adolescent runners with elevated bone turnover.
Barrack, MT, Van Loan, MD, Rauh, MJ, Nichols, JF
The American journal of clinical nutrition. 2010;92(3):652-9
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Young female runners are more likely to have a low bone mass for their age. It is thought that this might be partly due to them using more energy (calories) than they consume. This study looked at the relationship between nutrition intake and biomarkers of bone turnover in young female runners. Participants were competitive cross-country runners, aged 14-17. The girls ate their usual diet and kept a food diary for a week, to allow the researchers to analyse their nutritional intakes. Runners that had an elevated bone turnover consumed significantly less calories and calcium than the runners with a normal bone turnover. They were also more likely to have a lower body mass, fewer menstrual cycles, lower oestrogen and vitamin D levels, lower BMI and lower bone mass. The authors concluded that nutritional support to increase energy and calcium intake, and vitamin D levels may improve bone growth in young female runners.
Abstract
BACKGROUND Female adolescent runners have an elevated prevalence of low bone mass for agemdashan outcome that may be partially due to inadequate energy intake. OBJECTIVE The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover. DESIGN Thirty-nine cross-country runners (age: 15.7 plusmn 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked C-telopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dual-energy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age- and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal. RESULTS All abnormal BAP and CTX concentrations fell within the elevated ( ge 97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index lt 10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming lt 1300 mg Ca than did those with normal bone turnover. CONCLUSIONS Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.
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Hormonal and psychobehavioral predictors of weight loss in response to a short-term weight reduction program in obese women.
Hainer, V, Hlavatá, K, Gojová, M, Kunešová, M, Wagenknecht, M, Kopský, V, Pařízková, J, Hill, M, Nedvídková, J
Physiological research. 2008;57 Suppl 1:S17-S27
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Among the many factors that influence weight loss and weight management, metabolic and hormonal parameters have been increasingly explored as important predictors. The aim of this study was to reveal potential psycho-behavioural and hormonal factors as predictors of weight loss. A group of 67 overweight women were enrolled in a 3-week weight management programme in which food intake and physical activity were under strict control. This study indicated that a short-term weight management programme induced favourable changes in anthropometric, psycho-behavioural and hormonal indices. Changes in several hormone concentrations were significantly associated with the reduction of anthropometric parameters, however psycho-behavioural factors did not contribute to weight change in the programme.
Abstract
Among the factors influencing weight loss and maintenance, psychobehavioral, nutritional, metabolic, hormonal and hereditary predictors play an important role. Psychobehavioral factors influence adherence to lifestyle changes and thus weight loss maintenance. The outcome of short-term weight reduction treatment is mainly affected by changes in energy and nutrient intake and physical activity and thus the impact of hormones can possibly be obscured. In order to reveal hormonal determinants of weight loss, a 4-week in-patient comprehensive weight reduction program was introduced in which food intake and physical activity were under the strict control. Women (n = 67, BMI: 32.4+/-4.4 kg; age: 48.7+/-12.2 years) who exhibited stable weight on a 7 MJ/day diet during the first week of weight management were given a hypocaloric diet yielding daily energy deficit 2.5 MJ over the subsequent 3-week period. This treatment resulted in a mean weight loss of 3.80+/-1.64 kg. Correlation analysis revealed that baseline concentrations of several hormones were significantly associated either with a higher (free triiodothyronine, C-peptide, growth hormone, pancreatic polypeptide) or with a lower (insulin-like growth factor-I, cortisol, adiponectin, neuropeptide Y) reduction of anthropometric parameters in response to weight management. In a backward stepwise regression model age, initial BMI together with baseline levels of growth hormone, peptide YY, neuropetide Y and C-reactive protein predicted 49.8 % of the variability in weight loss. Psychobehavioral factors (items of the Eating Inventory, Beck Depression score) did not contribute to weight change induced by a well-controlled short-term weight reduction program.