RESUMO
There is a well-conceived notion that rate of recovery from strenuous exercise gets slower with age. However, it is unclear whether older adults who exercise habitually demonstrate slower rates of recovery. We determined whether older adults who are physically active demonstrate slower rates of recovery from unaccustomed strenuous exercise compared with younger peers. Healthy young sedentary (n=10, 28±2 years), young endurance-trained (n=15, 27±2 years), and older endurance-trained (n=14, 58±2 years) men and women were studied. Participants performed 45 min of downhill running at 65% of their maximal oxygen consumption. Visual analog pain scores of muscle groups increased at 24, 48, and 72 h in all three groups (p<0.05), and changes in the muscular pain scale of the legs was smaller in the older trained group than in the young trained group. Maximum isometric strengths at 90° decreased in all groups at 24 h, but the recovery rates were not different at 72 h among the groups. Plasma creatine kinase activity and myoglobin concentration increased at 24 h following downhill running and returned to baseline at 48 h in both the young and older trained groups. The present findings are not consistent with the prevailing notion that older trained adults have a slower rate of recovery from strenuous exercise.
Assuntos
Envelhecimento/fisiologia , Mialgia/fisiopatologia , Resistência Física/fisiologia , Aptidão Física/fisiologia , Corrida/fisiologia , Adulto , Creatina Quinase/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Músculo Esquelético/lesões , Músculo Esquelético/fisiopatologia , Mialgia/etiologia , Mioglobina/sangue , Consumo de Oxigênio/fisiologia , Amplitude de Movimento Articular , Corrida/lesõesRESUMO
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors and Editor-in-Chief. Some of the data presented in Figure 6C, F and G of the paper to which this corrigendum relates were reported incorrectly in the published article. After being contacted by the Journal, the authors discovered an unintentional error in how the original data were analyzed that could affect the accuracy of the subsequent analysis. The raw data were incorrectly grouped in the analysis software, thereby altering the comparisons. Therefore the authors wish to retract the paper and corrigendum and will recollect and reanalyze the data appropriately. The authors apologize for any inconvenience.
RESUMO
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors and Editor-in-Chief. Some of the data presented in Figure 6C, F and G of the above-titled paper were reported incorrectly in the published article. After being contacted by the Journal, the authors discovered an unintentional error in how the original data were analyzed that could affect the accuracy of the subsequent analysis. The raw data were incorrectly grouped in the analysis software, thereby altering the comparisons. Therefore the authors wish to retract the paper and will recollect and reanalyze the data appropriately. The authors apologize for any inconvenience.
RESUMO
Lifestyle modifications in the form of diet and exercise are generally the first-line approach to reduce hypertensive risk and overall cardiovascular disease (CVD) risk. Accumulating research evidence has revealed that consumption of non- and low-fat dairy products incorporated into the routine diet is an effective means to reduce elevated blood pressure and improve vascular functions. However, the idea of incorporating whole-fat or full-fat dairy products in the normal routine diet as a strategy to reduce CVD risk has been met with controversy. The aim of this review was to evaluate both sides of the argument surrounding saturated fat intake and CVD risk from the standpoint of dairy intake. Throughout the review, we examined observational studies on relationships between CVD risk and dairy consumption, dietary intervention studies using non-fat and whole-fat dairy, and mechanistic studies investigating physiological mechanisms of saturated fat intake that may help to explain increases in cardiovascular disease risk. Currently available data have demonstrated that whole-fat dairy is unlikely to augment hypertensive risk when added to the normal routine diet but may negatively impact CVD risk. In conclusion, whole-fat dairy may not be a recommended alternative to non- or low-fat dairy products as a mean to reduce hypertensive or overall CVD risk.
Assuntos
Doenças Cardiovasculares , Hipertensão , Animais , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia , Dieta , Gorduras na Dieta , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Hipertensão/prevenção & controle , Leite , Fatores de RiscoRESUMO
Damage to the microvascular endothelium is an important part of normal tissue injury after radiation exposure and driven by the production of pro-oxidants. The Ca2+/calmodulin-dependent protein kinase II is present in the mitochondrial matrix (mitoCaMKII) where it regulates Ca2+ uptake via the mitochondrial Ca2+ uniporter (MCU) and pro-oxidant production. Here, we demonstrate that radiation exposure disrupts endothelial cell barrier integrity in vitro, but can be abrogated by inhibition of mitoCaMKII, MCU, or opening of the mitochondrial transition pore. Scavenging of mitochondrial pro-oxidants with mitoTEMPO before, but not after irradiation, protected barrier function. Furthermore, markers of apoptosis and mitochondrial pro-oxidant production were elevated at 24â¯h following irradiation and abolished by mitoCaMKII inhibition. Endothelial barrier dysfunction was detected as early as 2â¯h after irradiation. Despite only mildly impaired mitochondrial respiration, the intracellular ATP levels were significantly reduced 4â¯h after irradiation and correlated with barrier function. MitoCaMKII inhibition improved intracellular ATP concentrations by increasing glycolysis. Finally, DNA double strand break repair and non-homologous end joining, two major drivers of ATP consumption after irradiation, were greatly increased but not significantly affected by mitoCaMKII inhibition. These findings support the hypothesis that mitoCaMKII activity is linked to mitochondrial pro-oxidant production, reduced ATP production, and loss of endothelial barrier function following irradiation. The inhibition of mitoCaMKII is a promising approach to limiting radiation-induced endothelial injury.
Assuntos
Canais de Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Endotélio/metabolismo , Mitocôndrias/metabolismoRESUMO
BACKGROUND: High consumption of low- and non-fat dairy products improves vascular dysfunction associated with elevated arterial blood pressure (BP). Currently, it is unknown if conventional full-fat dairy products improve vascular functions. OBJECTIVES: To determine if adding whole milk and full-fat dairy products to the normal routine diet improves vascular function in adults with elevated BP. DESIGN: Sixty adults (age ± SEM; 58 ± 2 years) with elevated BP (systolic/diastolic; 120-159/ < 99 mmHg) were randomized into a controlled crossover intervention trial consisting of two 4-week dietary periods. The high dairy condition consisted of adding four daily servings of whole milk or full-fat dairy products to the normal diet and eliminated all dairy intake during the control (no dairy) condition. A 2-week washout period separated the dietary conditions. RESULTS: Carotid-femoral pulse wave velocity (cfPWV) did not differ significantly between high dairy (11.3 ± 0.3 versus 10.9 ± 0.3 m/sec) and no dairy conditions (11.2 ± 0.3 versus 11.0 ± 0.3 m/sec). The results were consistent when ultrasound-derived vascular distension measures (arterial compliance, beta-stiffness index, and elastic modulus) were evaluated. Cardiovagal baroreceptor sensitivity (via Valsalva maneuver) demonstrated no significant difference for either dietary condition. Brachial arterial flow-mediated dilation (FMD) did not differ significantly during the high dairy (5.7 ± 0.5 versus 5.4 ± 0.6%) and no dairy conditions (6.5 ± 0.5 versus 5.6 ± 0.6%). CONCLUSIONS: The solitary addition of whole milk and full-fat dairy products has no effect on subclinical vascular function in adults with elevated BP.
Assuntos
Hipertensão , Análise de Onda de Pulso , Animais , Pressão Sanguínea , Laticínios , Dieta , Humanos , Pessoa de Meia-Idade , LeiteRESUMO
The purpose of the study was to determine whether muscle force, power, and optimal length were affected by 4 weeks of static or ballistic stretching. Twenty-nine males (age, 18-60 years) performed 4 maximal hip extensions to measure peak torque (PT), rate of torque development (RTD), work (W), and PT angle (PTA). Then, participants completed 4 weeks of static or ballistic flexibility training of the hip extensors followed by repetition of the testing protocol. After training, PT increased 5.3 +/- 19.0% in the static group (SG), 7.8 +/- 12.7% in the ballistic group (BG), and 6.1 +/- 17.9% in the control group (CG). RTD increased 4.8 +/- 22.7% in the SG, 3.6 +/- 28.0% in the BG and 9.7 +/- 24.0% in the CG. W increased 3.9 +/- 7.0% in the SG, 14.7 +/- 27.4% in the BG, and 5.5 +/- 9.5% in the CG. PTA changed little with a -1.6 +/- 6.6% decrease in the SG and increases of 0.86 +/- 4.1% in the BG and 0.18 +/- 8.7% in the CG. None of the results were statistically different between stretching group and CG (alpha = 0.05). These data suggest that 4 weeks of stretching have little effect on muscle strength, power, W, or length-tension relationship. PTA changed little, suggesting that a lengthening of the muscle with stretching did not occur. It is suggested that individuals can routinely stretch following exercise to maintain flexibility but should avoid stretching prior to exercise requiring high levels of muscle force. Before exercise that requires high muscular forces, individuals may perform dynamic, sport-specific exercises to increase blood flow, metabolic activity, temperature, and compliance of the muscle.
Assuntos
Força Muscular/fisiologia , Exercícios de Alongamento Muscular/métodos , Adolescente , Adulto , Quadril/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Dinamômetro de Força Muscular , Músculo Esquelético/fisiologia , TorqueRESUMO
BACKGROUND: Elevated android body fat increases the risk of developing cardiometabolic diseases. Postprandial hyperglycemia contributes to the proatherogenic metabolic state evident in android adiposity. Due to the insulinotropic effect of milk-derived proteins, postprandial hyperglycemia has been shown to be reduced with the addition of dairy products. The purpose of this study was to determine whether one serving of nonfat milk added to an oral glucose tolerance test (OGTT) could attenuate postprandial hyperglycemia in individuals with elevated android adiposity and whether these improvements would be associated with metabolic and/or peripheral hemodynamic effects. METHODS: In this placebo-controlled, randomized, crossover experimental study, 29 overweight/obese adults (26 ± 1 year) consumed an OGTT beverage (75 g glucose) combined with either nonfat milk (227 g) or a placebo control (12 g lactose + 8 g protein + 207 g water) that was matched for both carbohydrate and protein quantities. RESULTS: In the whole sample, blood glucose and insulin concentrations increased over time in both trials with no significant differences between trials. Relative increases in peak blood glucose response were significantly related to android body fat (p < 0.05). The subjects in the highest tertiles of android body fat displayed attenuated hyperglycemic responses as well as improvements in flow-mediated dilation (FMD) after milk intake. CONCLUSIONS: A single serving of nonfat milk may attenuate acute hyperglycemia in individuals with elevated android body fat offering a simple and convenient option for managing elevations in blood glucose.