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BACKGROUND: Prophylactic administration of tranexamic acid has been associated with reduced postpartum blood loss after cesarean delivery in several small trials, but evidence of its benefit in this clinical context remains inconclusive. METHODS: In a multicenter, double-blind, randomized, controlled trial, we assigned women undergoing cesarean delivery before or during labor at 34 or more gestational weeks to receive an intravenously administered prophylactic uterotonic agent and either tranexamic acid (1 g) or placebo. The primary outcome was postpartum hemorrhage, defined as a calculated estimated blood loss greater than 1000 ml or receipt of a red-cell transfusion within 2 days after delivery. Secondary outcomes included gravimetrically estimated blood loss, provider-assessed clinically significant postpartum hemorrhage, use of additional uterotonic agents, and postpartum blood transfusion. RESULTS: Of the 4551 women who underwent randomization, 4431 underwent cesarean delivery, 4153 (93.7%) of whom had primary outcome data available. The primary outcome occurred in 556 of 2086 women (26.7%) in the tranexamic acid group and in 653 of 2067 (31.6%) in the placebo group (adjusted risk ratio, 0.84; 95% confidence interval [CI], 0.75 to 0.94; P = 0.003). There were no significant between-group differences in mean gravimetrically estimated blood loss or in the percentage of women with provider-assessed clinically significant postpartum hemorrhage, use of additional uterotonic agents, or postpartum blood transfusion. Thromboembolic events in the 3 months after delivery occurred in 0.4% of women (8 of 2049) who received tranexamic acid and in 0.1% of women (2 of 2056) who received placebo (adjusted risk ratio, 4.01; 95% CI, 0.85 to 18.92; P = 0.08). CONCLUSIONS: Among women who underwent cesarean delivery and received prophylactic uterotonic agents, tranexamic acid treatment resulted in a significantly lower incidence of calculated estimated blood loss greater than 1000 ml or red-cell transfusion by day 2 than placebo, but it did not result in a lower incidence of hemorrhage-related secondary clinical outcomes. (Funded by the French Ministry of Health; TRAAP2 ClinicalTrials.gov number, NCT03431805.).
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Antifibrinolíticos/uso terapéutico , Cesárea/efectos adversos , Hemorragia Posparto/prevención & control , Ácido Tranexámico/uso terapéutico , Administración Intravenosa , Adulto , Antifibrinolíticos/efectos adversos , Transfusión Sanguínea/estadística & datos numéricos , Método Doble Ciego , Femenino , Humanos , Embarazo , Embolia Pulmonar/etiología , Ácido Tranexámico/efectos adversos , Trombosis de la Vena/etiologíaRESUMEN
OBJECTIVES: COVID-19 pandemic seems to be under control. However, despite the vaccines, 5 to 10% of the patients with mild disease develop moderate to critical forms with potential lethal evolution. In addition to assess lung infection spread, chest CT helps to detect complications. Developing a prediction model to identify at-risk patients of worsening from mild COVID-19 combining simple clinical and biological parameters with qualitative or quantitative data using CT would be relevant to organizing optimal patient management. METHODS: Four French hospitals were used for model training and internal validation. External validation was conducted in two independent hospitals. We used easy-to-obtain clinical (age, gender, smoking, symptoms' onset, cardiovascular comorbidities, diabetes, chronic respiratory diseases, immunosuppression) and biological parameters (lymphocytes, CRP) with qualitative or quantitative data (including radiomics) from the initial CT in mild COVID-19 patients. RESULTS: Qualitative CT scan with clinical and biological parameters can predict which patients with an initial mild presentation would develop a moderate to critical form of COVID-19, with a c-index of 0.70 (95% CI 0.63; 0.77). CT scan quantification improved the performance of the prediction up to 0.73 (95% CI 0.67; 0.79) and radiomics up to 0.77 (95% CI 0.71; 0.83). Results were similar in both validation cohorts, considering CT scans with or without injection. CONCLUSION: Adding CT scan quantification or radiomics to simple clinical and biological parameters can better predict which patients with an initial mild COVID-19 would worsen than qualitative analyses alone. This tool could help to the fair use of healthcare resources and to screen patients for potential new drugs to prevent a pejorative evolution of COVID-19. CLINICAL TRIAL REGISTRATION: NCT04481620. CLINICAL RELEVANCE STATEMENT: CT scan quantification or radiomics analysis is superior to qualitative analysis, when used with simple clinical and biological parameters, to determine which patients with an initial mild presentation of COVID-19 would worsen to a moderate to critical form. KEY POINTS: ⢠Qualitative CT scan analyses with simple clinical and biological parameters can predict which patients with an initial mild COVID-19 and respiratory symptoms would worsen with a c-index of 0.70. ⢠Adding CT scan quantification improves the performance of the clinical prediction model to an AUC of 0.73. ⢠Radiomics analyses slightly improve the performance of the model to a c-index of 0.77.
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COVID-19 , Humanos , SARS-CoV-2 , Pandemias , Modelos Estadísticos , Pronóstico , Estudios RetrospectivosRESUMEN
BACKGROUND: Although prophylactic tranexamic acid administration after cesarean delivery resulted in a lower incidence of calculated estimated blood loss of >1000 mL or red cell transfusion by day 2, its failure to reduce the incidence of hemorrhage-related secondary clinical outcomes (TRAnexamic Acid for Preventing Postpartum Hemorrhage Following a Cesarean Delivery trial) makes its use questionable. The magnitude of its effect may differ in women at higher risk of blood loss, including those with multiple pregnancies. OBJECTIVE: This study aimed to compare the effect of tranexamic acid vs placebo to prevent blood loss after cesarean delivery among women with multiple pregnancies. STUDY DESIGN: This was a secondary analysis of the TRAnexamic Acid for Preventing Postpartum Hemorrhage Following a Cesarean Delivery trial data, a double-blind, randomized controlled trial from March 2018 to January 2020 in 27 French maternity hospitals, that included 319 women with multiple pregnancies. Women with a cesarean delivery before or during labor at ≥34 weeks of gestation were randomized to receive intravenously 1 g of tranexamic acid (n=160) or placebo (n=159), both with prophylactic uterotonics. The primary outcome was a calculated estimated blood loss of >1000 mL or a red blood cell transfusion by 2 days after delivery. The secondary outcomes included clinical and laboratory blood loss measurements. RESULTS: Of the 4551 women randomized in this trial, 319 had a multiple pregnancy and cesarean delivery, and 298 (93.4%) had primary outcome data available. This outcome occurred in 62 of 147 women (42.2%) in the tranexamic acid group and 67 of 152 (44.1%) receiving placebo (adjusted risk ratio, 0.97; 95% confidence interval, 0.68-1.38; P=.86). No significant between-group differences occurred for any hemorrhage-related clinical outcomes: gravimetrically estimated blood loss, provider-assessed clinically significant hemorrhage, additional uterotonics, postpartum blood transfusion, arterial embolization, and emergency surgery (P>.05 for all comparisons). CONCLUSION: Among women with a multiple pregnancy and cesarean delivery, prophylactic tranexamic acid did not reduce the incidence of any blood loss-related outcomes.
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Antifibrinolíticos , Hemorragia Posparto , Ácido Tranexámico , Femenino , Embarazo , Humanos , Ácido Tranexámico/uso terapéutico , Hemorragia Posparto/epidemiología , Antifibrinolíticos/uso terapéutico , Cesárea/efectos adversos , Transfusión SanguíneaRESUMEN
Decreased health-related quality of life (HRQoL) is common in patients with cancer. We investigated the effects of dietary intervention and baseline nutritional status on worsening of HRQoL in older patients during chemotherapy. In this randomized control trial assessing the effect on mortality of dietary advice to increase dietary intake during chemotherapy, this post hoc analysis included 155 patients with cancer at risk of malnutrition. The effects of dietary intervention, baseline Mini Nutritional Assessment item scores, weight loss, and protein and energy intake before treatment on the worsening of HRQoL (physical functioning, fatigue) and secondary outcomes (Timed Up and Go test, one-leg stance time, depressive symptoms, basic (ADL), or instrumental (IADL) activities of daily living) were analyzed by multinomial regressions. Dietary intervention increased total energy and protein intake but had no effect on any examined outcomes. Worsening of fatigue and ADL was predicted by very low protein intake (< 0.8 g kg-1 day-1) before chemotherapy (OR 3.02, 95% CI 1.22-7.46, p = 0.018 and OR 5.21, 95% CI 1.18-22.73, p = 0.029 respectively). Increase in depressive symptomatology was predicted by 5.0-9.9% weight loss before chemotherapy (OR 2.68, 95% CI 1.10-6.80, p = 0.038). Nutritional intervention to prevent HRQoL decline during chemotherapy should focus on patients with very low protein intake along with those with weight loss.
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Dietoterapia/métodos , Ingestión de Energía/fisiología , Neoplasias/complicaciones , Terapia Nutricional/métodos , Calidad de Vida/psicología , Pérdida de Peso/fisiología , Anciano , Femenino , Humanos , Masculino , Neoplasias/tratamiento farmacológicoRESUMEN
An altered amino acid metabolism has been described in frail older adults which may contribute to muscle loss and functional decline associated with frailty. In the present investigation, we compared circulating amino acid profiles of older adults with physical frailty and sarcopenia (PF&S, n = 94), frail/pre-frail older adults with type 2 diabetes mellitus (F-T2DM, n = 66), and robust non-diabetic controls (n = 40). Partial least squares discriminant analysis (PLS-DA) models were built to define the amino acid signatures associated with the different frailty phenotypes. PLS-DA allowed correct classification of participants with 78.2 ± 1.9% accuracy. Older adults with F-T2DM showed an amino acid profile characterized by higher levels of 3-methylhistidine, alanine, arginine, ethanolamine, and glutamic acid. PF&S and control participants were discriminated based on serum concentrations of aminoadipic acid, aspartate, citrulline, cystine, taurine, and tryptophan. These findings suggest that different types of frailty may be characterized by distinct metabolic perturbations. Amino acid profiling may therefore serve as a valuable tool for frailty biomarker discovery.
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INTRODUCTION: Frail older people with diabetes often present with or develop walking impairments, in part due to lower-limb sensory-motor neuropathy. Several studies suggest a possible improvement of balance control using somatosensory stimulation. We undertook a novel randomized control trial, the aim of which was to observe whether use of this device for 1 month improves walking speed as measured in the 10-m fast walking speed test standardized to body size at month 1 (M1) (FWS). Secondary outcomes were the differences between intervention (VS) and control (C) in the 10-m normal walking speed test, step length, short physical performance battery, timed up and go test, and posturographic measures. METHODS: Subjects were aged ≥ 70 years and had had type 2 diabetes for at least 2 years. The intervention (VS) at home consisted of 22-min daily vibrating sequences with noise intensity set at 90% of the tactile threshold for each foot. The same device was used in group C but noise was set to 0. Compliance was retrieved from the device. RESULTS: Among 56 subjects, 27 were in the VS group and 29 in the C group; 35 subjects were frail, 15 were prefrail ,and 6 were non-frail. Bilateral neuropathy was present in 17 subjects. More than half of sessions were done in 36 subjects with no discernible difference according to intervention. At M1 there were no discernible differences in FWS between the groups [VS: 0.96 (0.53) cm s-1 cm-1, C: 0.94 (0.47) cm s-1 cm-1]. There were also no discernible differences in other outcomes, irrespective of the presence of bilateral neuropathy. CONCLUSION: In a cohort of frail, prefrail, or non-frail older subjects with diabetes, a 1-month intervention using a vibrating insole device did not alter measures of walking speed and related measures. Larger studies with longer term and different stimulation protocols are required to test this hypothesis more fully.
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Depression symptoms and lower health-related quality of life (HRQoL) are associated with inflammation. This multicenter dietary intervention was shown to reduce inflammation in older people. This was the main outcome. Here, we describe the effects on HRQoL, anxiety, and depressive symptoms according to inflammation status. Overall, 125 healthy older subjects (65-80 year) were recruited (Italy, France, and Germany) and randomized into four arms (A, Healthy diet (HD); B, HD plus De Simone Formulation probiotic blend; C, HD plus AISA d-Limonene; D, HD plus Argan oil). The HD was weight maintaining, rich in antioxidant vitamins, polyphenols, polyunsaturated fatty acids (n6: n3 ratio = 3:1), and fiber. Data on inflammatory parameters, mental (MCS) and physical (PCS) component summaries of HRQoL (SF-36), anxiety symptoms (STAI state), and depressive symptoms (CES-D) were collected before and after 56 days of intervention. Body fat mass proportion (BFM) was considered a co-variable. A decrease of CES-D score was seen in the four arms (A: -40.0%, p = 0.001; B: -32.5%, p = 0.023; C: -42.8%, p = 0.004; and D: -33.3%, p = 0.21). Within the subgroups of subjects with medium/high inflammation a similar decrease in CES-D score occurred in all groups (A: -44.8%, p = 0.021; B, -46.7%, p = 0.024; C, -52.2%, p = 0.039; D, -43.8%, p = 0.037). The effect of interventions on CES-D was not related to baseline inflammation. MCS-HRQoL improved in A and C. There was no change in anxiety or PCS-HRQoL. In this trial with no control group, a decrease in depressive symptoms in healthy older volunteers was observed after a 2-month healthy diet intervention, independently of inflammation but with possible limitations due to participation.
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Depresión/dietoterapia , Dieta Saludable , Suplementos Dietéticos , Calidad de Vida , Anciano , Anciano de 80 o más Años , Femenino , Humanos , MasculinoRESUMEN
Type 2 diabetes mellitus (T2DM) is a leading cause of disability globally. Frailty is a high-impact geriatric condition that increases the risk of negative health outcomes and imposes remarkable health and social burden. Both frailty and T2DM show multifaceted pathophysiology, phenotypic heterogeneity, and fluctuating manifestations that challenge their management, especially when the two conditions co-occur. Muscle wasting and its correlates (e.g., metabolic perturbations and functional decline) that underlie frailty may exacerbates clinical manifestations of T2DM in older people, resulting in worse prognosis. The intrinsic complexity of frailty and T2DM has hampered the identification of clinically meaningful biomarkers to track the clinical progression of the two conditions over time and to monitor the efficacy of pharmacological and lifestyle interventions. Here, we propose an innovative approach for biomarker identification that couples multi-platform analytical determinations with chemometric modeling strategies. This novel multi-marker discovery process is described in the context of the "Metabolic biomarkers of frailty in older people with type 2 diabetes mellitus" (MetaboFrail) study that aimed at identifying metabolic biomarkers of frailty in functionally limited older persons with T2DM.
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Biomarcadores/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Anciano Frágil , Fragilidad/metabolismo , Anciano , Anciano de 80 o más Años , Humanos , Sarcopenia/metabolismoRESUMEN
Diabetes and frailty are highly prevalent conditions that impact the health status of older adults. Perturbations in protein/amino acid metabolism are associated with both functional impairment and type 2 diabetes mellitus (T2DM). In the present study, we compared the concentrations of a panel of circulating 37 amino acids and derivatives between frail/pre-frail older adults with T2DM and robust non-diabetic controls. Sixty-six functionally impaired older persons aged 70+ with T2DM and 30 age and sex-matched controls were included in the analysis. We applied a partial least squares-discriminant analysis (PLS-DA)-based analytical strategy to characterize the metabotype of study participants. The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 94.1 ± 1.9% for frail/pre-frail persons with T2DM and 100% for control participants. Functionally impaired older persons with T2DM showed higher levels of 3-methyl histidine, alanine, arginine, glutamic acid, ethanolamine sarcosine, and tryptophan. Control participants had higher levels of ornithine and taurine. These findings indicate that a specific profile of amino acids and derivatives characterizes pre-frail/frail older persons with T2DM. The dissection of these pathways may provide novel insights into the metabolic perturbations involved in the disabling cascade in older persons with T2DM.
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Aminoácidos Cíclicos/sangre , Diabetes Mellitus Tipo 2/sangre , Fragilidad/sangre , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Estudios de Casos y Controles , Diabetes Mellitus Tipo 2/complicaciones , Femenino , Fragilidad/complicaciones , Humanos , Análisis de los Mínimos Cuadrados , Masculino , Metaboloma , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
The application of a stochastic mechanical noise has been shown to improve plantar touch sensitivity in patients with diabetic neuropathy and balance control. The present work aimed to test the feasibility of a specially designed vibrating device on gait and posture in older patients with type 2 diabetes with special interest on potential side effect (sensation of needles or tingling, dizziness or falls) before further investigations. For this, gait and balance tests were performed in 29 older out and in-patients (mean age 84 years, Barthel index ≥ 60/100) immediately before and after a 19 min plantar vibrating sequence, as well as 15 min after. These tests included posturographic measurements under eyes closed and static conditions and clinical gait tests (Short Physical Performance Battery and Timed-Up and Go tests). The results showed that no side effect was measured immediately, 15 min and up to 30 days after the vibration sequence. Besides, postural and clinical gait tests showed global positive effects at immediate and 15 min follow-up. Further investigation are now necessary to determine whether a daily stimulation sequence for a given time would lead to long-term positive effects on daily living (NCT01654341; https://clinicaltrials.gov/ct2/show/NCT01654341).
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BACKGROUND: Older adults with cancer experience negative long-term functional effects of both cancer and treatments. Exercise may minimize their age-related and cancer-related functional decline. METHODS: We conducted a multicentre open-label 12 month randomized clinical trial with two parallel arms including participants aged ≥70 years with lymphoma or carcinoma requiring curative treatment. The study started at the beginning of any phase of cancer treatment (surgery, chemotherapy, or radiotherapy). The usual care group (UCG) received the current national recommendations in physical activity (a guideline without specific counselling). The intervention group (IG) received 1 year phoned physical activity advice individually adapted to physical assessment (twice a month during the first 6 months and then monthly). The primary outcome was the proportion of subjects with a 1 year decreased short physical performance battery (SPPB) score of 1 point or more. Physical, cognitive, and clinical secondary outcomes were also investigated. RESULTS: We allocated 301 participants (age 76.7 ± 5.0, female 60.6%) to each group. At baseline, the median SPPB was 10/12 in both groups. Breast was the most frequent tumour site (35.7%). After 1 year, 14.0% of participants in the UCG and 18.7% in the IG had a decrease in SPPB score of 1 point or more (P = 0.772). At 2 years, there was no difference in SPPB, gait speed, International Physical Activity Questionnaire score, and verbal fluency. Subgroup analyses after 2 years showed a decline in SPPB for 29.8% of UCG and 5.0% of IG breast cancer participants (P = 0.006), in 21.7% of UCG and 6.2% of IG female participants (P = 0.019), and in 24.5% of UCG and 11.1% of IG normal nutritional status participants (P = 0.009). Falls, hospitalization, institutionalization, and death rates were similar in both groups. CONCLUSIONS: Personalized phoned physical activity advice had not reduced functional decline at 1 year but provided preliminary evidence that may prevent physical performance decline at 2 years in older adults with breast cancer.
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Ejercicio Físico , Evaluación Geriátrica , Neoplasias/epidemiología , Rendimiento Físico Funcional , Accidentes por Caídas , Factores de Edad , Anciano , Anciano de 80 o más Años , Femenino , Hospitalización , Humanos , Incidencia , Masculino , Factores SocioeconómicosRESUMEN
BACKGROUND: Type 2 diabetes, a highly prevalent chronic disease, is associated with increasing frailty and functional decline in older people. We aimed to evaluate the effectiveness of a multimodal intervention on functional performance in frail and pre-frail participants aged ≥70 years with type 2 diabetes mellitus. METHODS: The MID-Frail study was a cluster-randomized multicenter clinical trial conducted in 74 trial sites across seven European countries. The trial recruited 964 participants who were aged >70 years [mean age in intervention group, 78.4 (SD 5.6) years, 49.2% male and 77.6 (SD 5.29) years, 52.4% male in usual care group], with type diabetes mellitus and determined to be frail or pre-frail using Fried's frailty phenotype. Participants were allocated by trial site to follow either usual care (UCG) or intervention procedures (IG). Intervention group participants received a multimodal intervention composed of (i) an individualized and progressive resistance exercise programme for 16 weeks; (ii) a structured diabetes and nutritional educational programme over seven sessions; and (iii) Investigator-linked training to ensure optimal diabetes care. Short Physical Performance Battery (SPPB) scores were used to assess change in functional performance at 12 months between the groups. An analysis of the cost-effectiveness of the intervention was undertaken using the incremental cost-effectiveness ratio (ICER). Secondary outcomes included mortality, hospitalization, institutionalization, quality of life, burden on caregivers, the frequency and severity of hypoglycaemia episodes, and the cost-effectiveness of the intervention. RESULTS: After 12 months, IG participants had mean SPPB scores 0.85 points higher than those in the UCG (95% CI, 0.44 to 1.26, P < 0.0001). Dropouts were higher in frail participants and in the intervention group, but significant differences in SPPB between treatment groups remained consistent after sensitivity analysis. Estimates suggest a mean saving following intervention of 428.02 EUR (2016) per patient per year, with ICER analysis indicating a consistent benefit of the described health care intervention over usual care. No statistically significant differences between groups were detected in any of the other secondary outcomes. CONCLUSIONS: We have demonstrated that a 12 month structured multimodal intervention programme across several clinical settings in different European countries leads to a clinically relevant and cost-effective improvement in the functional status of older frail and pre-frail participants with type 2 diabetes mellitus.
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Diabetes Mellitus Tipo 2/terapia , Calidad de Vida/psicología , Anciano , Terapia Combinada , Femenino , Humanos , Masculino , Resultado del TratamientoRESUMEN
BACKGROUND & AIMS: Several studies with diabetes-specific formulas (DSFs) for hyperglycaemic patients in need of nutritional support have been conducted in non-malnourished patients, mainly comparing products with varying macronutrient compositions. Here, the effect of a high energy, high protein DSF on postprandial responses was compared to a product with a similar macronutrient composition in malnourished or at risk of malnutrition patients with type 2 diabetes. METHODS: In this randomised, double-blind cross-over study, 20 patients were included. After overnight fasting, patients consumed 200 mL of a DSF or standard supplement (control) (19.6 g protein, 31.2 g carbohydrates and 10.6 g fat), while continuing their anti-diabetic medication. The formulas differed in type of carbohydrates and presence of fibre. The postprandial glucose, insulin and glucagon responses were monitored over 4 h. Data were analysed with a Linear Mixed Model, and results of the modified ITT population (n = 19) are shown. RESULTS: Postprandial glucose response as incremental area under the curve (iAUC), was lower after consumption of DSF compared with control (489.7 ± 268.5 (mean ± SD) vs 581.3 ± 273.9 mmol/L min, respectively; p = 0.008). Also, the incremental maximum concentration of glucose (iCmax) was lower for DSF vs control (3.5 ± 1.4 vs 4.0 ± 1.4 mmol/L; p = 0.007). Postprandial insulin and glucagon levels, expressed as iAUC or iCmax, were not significantly different between groups. CONCLUSIONS: Consumption of a high energy, high protein DSF by older malnourished or at risk of malnutrition type 2 diabetes patients resulted in a significantly lower glucose response compared to control. These data suggest that the use of a DSF is preferred for patients with diabetes in need of nutritional support.
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Glucemia/metabolismo , Diabetes Mellitus Tipo 2 , Dieta Rica en Proteínas , Alimentos Formulados , Desnutrición , Anciano , Anciano de 80 o más Años , Estudios Cruzados , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/metabolismo , Método Doble Ciego , Femenino , Humanos , Insulina/sangre , Masculino , Desnutrición/complicaciones , Desnutrición/metabolismo , Desnutrición/prevención & controlRESUMEN
In this study, we examined the effects of three recovery intensities on time spent at a high percentage of maximal oxygen uptake (t90[Vdot]O(2max)) during a short intermittent session. Eight endurance-trained male adolescents (16 +/- 1 years) performed four field tests until exhaustion: a graded test to determine maximal oxygen uptake ([Vdot]O(2max); 57.4 +/- 6.1 ml x min(-1) . kg(-1)) and maximal aerobic velocity (17.9 +/- 0.4 km x h(-1)), and three intermittent exercises consisting of repeat 30-s runs at 105% of maximal aerobic velocity alternating with 30 s active recovery at 50% (IE(50)), 67% (IE(67)), and 84% (IE(84)) of maximal aerobic velocity. In absolute values, mean t90[Vdot]O(2max) was not significantly different between IE(50) and IE(67), but both values were significantly longer compared with IE(84). When expressed in relative values (as a percentage of time to exhaustion), mean t90[Vdot]O(2max) was significantly higher during IE(67) than during IE(50). Our results show that both 50% and 67% of maximal aerobic velocity of active recovery induced extensive solicitation of the cardiorespiratory system. Our results suggest that the choice of recovery intensity depends on the exercise objective.
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Tolerancia al Ejercicio/fisiología , Consumo de Oxígeno/fisiología , Carrera/fisiología , Deportes , Adolescente , Factores de Edad , Ejercicio Físico/fisiología , Prueba de Esfuerzo , Humanos , Masculino , Factores de TiempoRESUMEN
Stretch-shortening cycle (SSC)-type fatigue is associated with acute and delayed functional defects, and appears to be a useful model to reveal the flexibility of both central and reflex adjustments to the contractile failure. SSC fatigue was induced in an experimental (EXP) group (n=6) on a sledge ergometer with an exhaustive rebound exercise with submaximal effort. The acute (POST) and 2-day delayed (2D) neuromuscular changes with fatigue were examined in a short submaximal rebound task (REBOUND) and in a maximal isometric plantarflexion test (ISOM). The EXP group results were compared to those of a control group (n=6) who did not perform the exhaustive SSC exercise and did not present any change in the tests. In the EXP group, the ISOM test revealed mostly a large decrease in maximal plantarflexion force at 2D that was correlated with the reduced mean soleus muscle (SOL) activation. Indicating "task-dependent" fatigue effects on the neural changes, the REBOUND test revealed both acute and delayed increases in SOL activation. Supporting central neural changes, SOL preactivation increased in POST and 2D. The neural flexibility along time and across muscles was demonstrated by the shifted increase in SOL activation from the braking phase in POST to the push-off phase in 2D, and associated increased gastrocnemius medialis preactivation in 2D. In contrast, activation during the stretch-reflex period was constant in POST, and decreased in 2D. These results would support the influence of musculotendinous afferents on the flexible neural adjustments to the SSC-induced contractile failure.