Background:The respiratory exchange ratio (RER) indirectly shows the muscle’s oxidative capacity to get energy. Sedentarism, exercise and physically active lifestyles modify it. For that reason, this study evaluates the associations between RER during sub-maximum exercise and other well established fitness indicators (body fat, maximum heart rate, maximum O2 uptake, workload, and lactate threshold), in physically active trained and untrained men.Methods:The RER, O2 uptake and blood lactate were measured in eight endurance trained and eight untrained men (age, 22.9 ± 4.5 vs. 21.9 ± 2.8 years; body mass, 67.1 ± 5.4 vs. 72.2 ± 7.7 kg; body fat, 10.6 ± 2.4% vs. 16.6 ± 3.8% and maximum O2 uptake, 68.9 ± 6.3 vs. 51.6 ± 5.8 ml•kg−1•min−1), during maximum exercise test and during three different sub-maximum exercises at fixed workload: below, within or above the lactate threshold.Results:Endurance trained men presented higher O2 uptake, lower blood lactate concentrations and lower RER values than those in untrained men at the three similar relative workloads. Even though with these differences in RER, a strong association (p < 0.05) of RER during sub-maximum exercise with the other well established fitness indicators was observed, and both maximum O2 uptake and lactate threshold determined more than 57% of its variance (p < 0.05).Conclusions:These data demonstrate that RER measurement under sub-maximum exercise conditions was well correlated with other established physical fitness indicators, despite training condition. Furthermore, the results suggest that RER could help obtain an easy approach of fitness status under low exercise intensity and could be utilized in subjects with reduced exercise tolerance.

Background: Spirulina maxima is a filamentous cyanobacterium used as food supplement because of its high nutrient contents. It has been experimentally proven, in vivo and in vitro that posses several pharmacological properties. The purpose of this study was to evaluate the effects of Spirulina maxima orally supplied (4.5 g/day, for 6 weeks) to a sample of 36 subjects (16 men and 20 women, with ages between 18-65 years) on serum lipids, glucose, aminotransferases and on blood pressure. The volunteers did not modify their dietary habits or lifestyle during the whole experimental period. From each subject, a sample of blood was drawn in fasting state of 12 hours to determi the plasma concentrations of glucose, triacylglycerols (TAG), total cholesterol (TC), cholesterol associated to high density lipoprotein (HDL-C) and aspartate aminotransferase (AST). Anthropometric measurements including systolic (SYST-P) and diastolic (DIAST-P) blood pressure, height, weight and Body Mass Index (BMI) were also recorded.

BackgroundOxidative damage has been proposed as a possible mechanism involved in lead toxicity, specially affecting the liver and kidney. Previous studies have shown the antioxidant effect of Spirulina maxima in several experimental models of oxidative stress. The current study was carried out to evaluate the antioxidant activity of Spirulina maxima against lead acetate-induced hyperlipidemia and oxidative damage in the liver and kidney of male rats. Control animals were fed on a standard diet and did not receive lead acetate (Control group). Experimental animals were fed on a standard laboratory diet with or without Spirulina maxima 5% in the standard laboratory diet and treated with three doses of lead acetate (25 mg each/weekly, intraperitoneal injection) (lead acetate with Spirulina, and lead acetate without Spirulina groups).ResultsThe results showed that Spirulina maxima prevented the lead acetate-induced significant changes on plasma and liver lipid levels and on the antioxidant status of the liver and kidney. On the other hand, Spirulina maxima succeeded to improve the biochemical parameters of the liver and kidney towards the normal values of the Control group.ConclusionsIt was concluded that Spirulina maxima has protective effects on lead acetate-induced damage, and that the effects are associated with the antioxidant effect of Spirulina.

Two hours of 60 Hz EMF exposure might immediately alter the metabolism of free radicals, decreasing SOD activity in plasma and GSH content in heart and kidney, but does not induce immediate lipid peroxidation. Oxidative stress induced by movement restraint was stronger than that produced by EMF.

Background:Hatha Yoga (HY) can be an alternative to improve physical activity in middle-aged and older women. However, conventional HY (CHY) exercising may not result in enough training stimulus to improve cardiovascular fitness. The purpose of this study was to evaluate the effect of an intensive HY intervention (IHY) on cardiovascular risk factors in middle-aged and older women from Northern Mexico.Materials and Methods:In this prospective quasiexperimental design, four middle-aged and nine older CHY practicing females (yoginis) were enrolled into an 11-week IHY program consisting of 5 sessions/week for 90 min (55 sessions). The program adherence, asana performance, and work intensity were assessed along the intervention. Anthropometric [body mass index (BMI), % body fat and Σ skin folds], cardiovascular fitness [maximal expired air volume (VEmax), maximal O2 consumption (VO2max), maximal heart rate (HRmax), systolic (BPs) and diastolic blood pressure (BPd)], biochemical [glucose, triacylglycerols (TAG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)], and dietary parameters were evaluated before and after IHY.Results:Daily caloric intake (~1,916 kcal/day), program adherence (~85%), and exercising skills (asana performance) were similar in both middle-aged and older women. The IHY program did not modify any anthropometric measurements. However, it increased VO2max and VEmax and HDL-C while TAG and LDL-C remained stable in both middle-aged and older groups (P < 0.01).Conclusions:The proposed IHY program improves different cardiovascular risk factors (namely VO2max and HDL-C) in middle-aged and older women.

There are several reports suggesting that Spirulina (Arthrospira) may have a beneficial effect in the prevention of cardiovascular diseases. Here we review the results of studies on the effects of dietary Spirulina on the vasomotor reactivity of aortic rings excised from either lean or obese Wistar rats. We also review preliminary results on the effects of Spirulina intake on plasma lipids and blood pressure in humans. The results of the former studies strongly suggest that Spirulina induces a tone-related increase in the synthesis/release of nitric oxide by the endothelium as well as an increase in the synthesis/release of a vasodilating cyclooxygenase-dependent metabolite of arachidonic acid and/or a decrease in the synthesis/release of a vasoconstricting eicosanoid by the endothelium. In humans, Spirulina maxima intake decreases blood pressure and plasma lipid concentrations, especially triacylglycerols and low-density lipoprotein-cholesterol, and indirectly modifies the total cholesterol and high-density lipoprotein-cholesterol values.

(1) Background: Spirulina (Arthrospira) maxima has shown beneficial effects such as being anti-dyslipidemic, antiviral, antioxidant and antihypertensive. However, there are few and limited clinical studies. (2) Methods: a prospective, randomized, parallel pilot study of 4.5 g administration of Spirulina maxima or placebo for 12 weeks in 16 patients with systemic arterial hypertension (SAH) undergoing treatment with angiotensin-converting enzyme (ACE) inhibitors was performed to assess the effects on endothelial damage and oxidative stress indicators. The blood levels of sICAM-1, sVCAM-1, endothelin-1, and sE-selectin were quantified; the activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and concentrations of reduced glutathione, oxidized glutathione, and thiobarbituric acid reactive substances, were also quantified before and after the treatment period. (3) Results: There were statistically significant (p < 0.05) decreases in systolic blood pressure, sVCAM-1, sE-selectin and endothelin-1 levels, and increases in glutathione peroxidase activity and oxidized glutathione levels. (4) Conclusion: The effects found in the present study agree with antihypertensive and antioxidant effects previously reported for Spirulina maxima. However, this is the first report about the effects on indicators of endothelial damage. More research in this field is necessary to gain an insight into the effects of Spirulina on these indicators.

Backgound: The effects of extremely low-frequency electromagnetic fields (ELF-EMF) on the blood serum and liver lipid concentrations of male Wistar rats were assessed.Methods: Animals were exposed to a single stimulation (2 h) of ELF-EMF (60 Hz, 2.4 mT) or shamstimulated and thereafter sacrificed at different times (24, 48 or 96 h after beginning the exposure).Results: Blood lipids showed, at 48 h stimulated animals, a significant increase of cholesterol associated to high density lipoproteins (HDL-C) than those observed at any other studied time. Free fatty acid serum presented at 24 h significant increases in comparison with control group. The other serum lipids, triacylglycerols and total cholesterol did not show differences between groups, at any time evaluated. No statistical differences were shown on total lipids of the liver but total cholesterol was elevated at 24 h with a significant decrease at 96 h (p = 0.026). The ELF-EMF stimulation increased the liver content of lipoperoxides at 24 h. Conclusion:Single exposures to ELF-EMF increases the serum values of HDL-C, the liver content of lipoperoxides and decreases total cholesterol of the liver. The mechanisms for the effects of ELF-EMF on lipid metabolism are not well understand yet, but could be associated to the nitric oxide synthase EMF-stimulation.