Exercise-induced changes in hematocrit and hematocrit/viscosity ratio in male rugby players.

We investigated whether the concept of hematocrit/viscosity (h/η) ratio explains the "paradox of hematocrit in athletes", by calculating a "theoretical optimal hematocrit" (i.e., associated with the higher h/η value predicted with Quemada's equation from plasma viscosity, and erythrocyte rigidity index) before and after exercise.

One-year follow-up of blood viscosity factors and hematocrit/viscosity ratio in elite soccer players.

We investigated to what extent a prediction of the 'ideal' hematocrit based on individual hemorheological profile with an equation of viscosity is relevant in trained athletes, and how the agreement between theoretical and actual values is modified by changes in training volume and performance. Elite soccer players (national level: 18-32 yr, weight 61-83 kg, body mass index 20.9-25.

« Optimal » vs actual hematocrit in obesity and overweight.

Equations of blood viscosity provide a prediction of the 'optimal' hematocrit' (hct) as the hct resulting in the highest value of the bell-shaped curve of hematocrit/viscosity ratio h/η. We investigated if overweight and obesity have an influence on these parameters. We compared 32 normal weight subjects, 40 overweight (BMI 25-30) and 38 obese subjects.

Skeletal Muscle Insulin Resistance and Absence of Inflammation Characterize Insulin-Resistant Grade I Obese Women.

Context: Obesity is associated with insulin-resistance (IR), the key feature of type 2 diabetes. Although chronic low-grade inflammation has been identified as a central effector of IR development, it has never been investigated simultaneously at systemic level and locally in skeletal muscle and adipose tissue in obese humans characterized for their insulin sensitivity.

Objectives: We compared metabolic parameters and inflammation at systemic and tissue levels in normal-weight and obese subjects with different insulin sensitivity to better understand the mechanisms involved in IR development.

Hemorheologic effects of low intensity endurance training in type 2 diabetic patients: A pilot study.

We previously reported that low intensity endurance training in sedentary patients suffering from the metabolic syndrome improves blood rheology, mostly due to a decrease in plasma viscosity correlated with an increase in cardiorespiratory fitness. We investigated whether these findings can be extended to type-2 diabetics. 22 diabetics (11 women and 10 men, age: 52.

Are metabolically healthy obese patients also hemorheologically healthy?

We examined whether "metabolically healthy obesity" (MHO) is associated or not with hemorheologic alterations. We studied 110 subjects: 32 normal weight; 40 overweight; 38 obese. Overweight and obese subjects were divided into two subgroups according to the occurrence or not of a metabolic syndrome (METS).

Nutritional and metabolic determinants of blood rheology differ between trained and sedentary individuals.

Body composition and nutrition have been reported to be correlated with blood rheology. However, in sedentary and in physically active individuals these relationships seem to be not exactly similar. This study investigated whether exercise training status influences these relationships.

Grape polyphenols prevent fructose-induced oxidative stress and insulin resistance in first-degree relatives of type 2 diabetic patients.

Objective: To assess the clinical efficacy of nutritional amounts of grape polyphenols (PPs) in counteracting the metabolic alterations of high-fructose diet, including oxidative stress and insulin resistance (IR), in healthy volunteers with high metabolic risk.

Research Design And Methods: Thirty-eight healthy overweight/obese first-degree relatives of type 2 diabetic patients (18 men and 20 women) were randomized in a double-blind controlled trial between a grape PP (2 g/day) and a placebo (PCB) group. Subjects were investigated at baseline and after 8 and 9 weeks of supplementation, the last 6 days of which they all received 3 g/kg fat-free mass/day of fructose.

Blood rheology and body composition as determinants of exercise performance in male soccer players.

The aim of this study was to assess on a large series of soccer players our previous reports on blood rheology and exercise performance. In 99 soccer players (Age 24,17 ± 0,42 yr; weight 75,87 ± 0,89 kg; VO2max 46,86 ± 0,95 mL/min/kg) an exercise test was performed for measuring maximal aerobic capacity and we measured blood viscosity at high shear rate (MT90 viscometer) and RBC aggregation (Myrenne MK1). The French questionnaire developped by the consensus group on overtraining of the French Society of Sports Medicine (SFMS) was also employed.

Body composition and exercise performance as determinants of blood rheology in middle-aged patients exhibiting the metabolic syndrome.

Aerobic capacity and performance are associated with increased blood fluidity, while sedentarity leads to decreased exercise performance, and blood hyperviscosity. We aimed at investigating the relationships among body composition, blood rheology and exercise performance in this situation. In 46 sedentary subjects (53.

Assessment of insulin sensitivity (S I) and glucose effectiveness (S G) from a standardized hyperglucidic breakfast test in type 2 diabetics exhibiting various levels of insulin resistance.

We investigated the measurement of insulin sensitivity (S I) with a standardized hyperglucidic breakfast (SHB) compared to minimal model analysis of an intravenous glucose tolerance test (S I-IVGTT) in 17 patients clinically referred as type 2 diabetics, not yet treated by insulin, and representing a wide range of body mass index and S I. To classify the patients, ten meal-tolerance test-based calculations of S I (MTT-S I) were compared to S I-IVGTT, and their reference values and distribution were measured on a separate sample of 200 control SHBs and 209 control IVGTTs. Eight MTT-SI indices exhibit significant correlations with S I-IVGTT: Mari's OGIS index, BIGTT-SI|0-30-120, BIGTT-SI|0-60-120, 1/G b I m, Caumo's oral minimal model (OMM), Sluiter's index "A" = 10(4)/(I p·G p), Matsuda's composite index given by the formula ISIcomp = 10(4)/(I b G b I m G m)(0.

Comparative validation of the growth hormone-releasing hormone and arginine test for the diagnosis of adult growth hormone deficiency using a growth hormone assay conforming to recent international recommendations.

Context: The GHRH plus arginine (GHRH+Arg) test is a promising alternative to the insulin tolerance test (ITT) for diagnosis of adult GH deficiency (AGHD).

Objectives: The objectives of the study were to validate the GHRH+Arg test for diagnosis of AGHD, using the ITT as comparator and a GH assay calibrated according to recent international recommendations, and to study the repeatability and tolerance of both tests.

Design: This was a multicenter, randomized, open-label, phase III study.

Relationship between blood lactate concentration and substrate utilization during exercise in type 2 diabetic postmenopausal women.

Increased blood lactate concentration and alterations of substrate utilization have been shown to be partly involved in development of insulin resistance in obese and type 2 diabetic patients. As blood represents the first great distribution space and participates to lactate exchange in whole body, we investigated lactate transport in red blood cells at rest and the potential relationships between elevated blood lactate and substrate utilization in 7 obese controls and 7 obese type 2 diabetic postmenopausal women during an incremental exercise test. Blood samples were collected at rest, 30%, 50%, and 60% of maximal power and at 8 and 20 minutes of recovery time.