Hypoxia induced by low O
pressure is responsible for several physiological and behavioral alterations. Changes in physiological systems are frequent, including inflammation and psychobiological ...declines such as mood and cognition worsening, resulting in increased reaction time, difficulty solving problems, reduced memory and concentration. The paper discusses the possible relationship between glutamine supplementation and worsening cognition mediated by inflammation induced by high altitude hypoxia. The paper is a narrative literature review conducted to verify the effects of glutamine supplementation on psychobiological aspects. We searched MEDLINE/PubMed and Web of Science databases and gray literature by Google Scholar for English articles. Mechanistic pathways mediated by glutamine suggest potential positive effects of its supplementation on mood and cognition, mainly its potential effect on inflammation. However, clinical studies are scarce, making any conclusions impossible. Although glutamine plays an important role and seems to mitigate inflammation, clinical studies should test this hypothesis, which will contribute to a better mood and cognition state for several people who suffer from problems mediated by hypoxia.
Rating of Perceived Exertion (RPE) is a subjective scale to monitor overload and fatigue during exercise. Hypoxia may worsen the perception of fatigue, compromising the self-reported perception of ...effort and increasing RPE. The objective was to evaluate the effects of carbohydrate (CHO) supplementation on RPE during exercise in hypoxia simulating 4200 m.
Eight male physically active volunteers performed two exercises at 50% VO
and 1% slope: exercise in hypoxia + placebo or exercise in hypoxia + CHO (6% maltodextrin) with supplementation at 20, 40, and 60 min during exercise. Oxygen Saturation (SaO
%) was assessed at baseline and after exercise, while RPE and HR were measured each 10 min during the trial.
SaO
% decreased after exercise in both conditions of hypoxia compared to rest. The RPE did not differ between groups. However, the RPE increased in hypoxia after 20 min of exercise in relation to 10 min. The Area Under the Curve (AUC) of RPE was lower in hypoxia + CHO compared to hypoxia. The AUC of the HR/RPE ratio in the hypoxia + CHO group was higher in relation to hypoxia.
Our results indicate that CHO supplementation does not change RPE induced by 60 min of exercise at 50% VO
in hypoxia equivalent to 4200 m at the different times analyzed. However, in hypoxia + CHO the (AUC)-60 min of total RPE decreased during exercise, while the heart rate/RPE ratio improved, indicating lower RPE in the hypoxic environment.
Background
Exercise under hypoxic conditions represents an additional stress in relation to exercise in normoxia. Hypoxia induces oxidative stress and inflammation as mediated through tumour necrosis ...factor (TNF)‐α release that might be exacerbated through exercise. In addition, vitamin E supplementation might attenuate oxidative stress and inflammation resulting from hypoxia during exercise. The present study aimed to evaluate the effects of vitamin E supplementation (250 mg) on inflammatory parameters and cellular damage after exercise under hypoxia simulating an altitude of 4200 m.
Methods
Nine volunteers performed three sessions of 60 min of exercise (70% maximal oxygen uptake) interspersed for 1 week under normoxia, hypoxia and hypoxia after vitamin E supplementation 1 h before exercise. Blood was collected before, immediately after and at 1 h after exercise to measure inflammatory parameters and cell damage.
Results
Percentage oxygen saturation of haemoglobin decreased after exercise and recovered 1 h later in the hypoxia + vitamin condition (P < 0.05). Supplementation decreased creatine kinase (CK)‐TOTAL, CK‐MB and lactate dehydrogenase 1 h after exercise (P < 0.05). The exercise in hypoxia increased interleukin (IL)‐6, TNF‐α, IL‐1ra and IL‐10 immediately after exercise (P < 0.05). Supplementation reversed the changes observed after exercise in hypoxia without supplementation (P < 0.05).
Conclusions
We conclude that 250 mg of vitamin E supplementation at 1 h before exercise reduces cell damage markers after exercise in hypoxia and changes the concentration of cytokines, suggesting a possible protective effect against inflammation induced by hypoxia during exercise.
The rating of perceived exertion (RPE) indicates the feeling of fatigue. However, hypoxia worsens the condition and can worsen RPE. We evaluated whether carbohydrate and glutamine supplementation ...alters RPE and physiological markers in running at 70% peak oxygen uptake until exhaustion in a simulated altitude of 4500 m. Nine volunteers underwent three running tests at 70% peak oxygen uptake until exhaustion: (1) hypoxia and placebo, (2) hypoxia and 8% maltodextrin, and (3) hypoxia after six days of glutamine supplementation (20 g/day) and 8% maltodextrin. The exercise and supplementation were randomized and double-blinded. Lactate, heart rate, haemoglobin O
saturation (SpO
%), and RPE (6-20 scale) were analyzed at the 15th and 30th min. The level of significance was set at
≤ 0.05. SpO
% decreased at the 15th and 30th minutes compared to resting in placebo, carbohydrate, and glutamine supplementation. RPE increased at the 30th minute compared to the 15th minute in placebo and carbohydrate supplementation; however, there was no difference in the glutamine supplementation condition. Heart rate and lactate increased after the 15th and 30th minutes compared to resting, similar to the three conditions studied. We conclude that previous supplementation with glutamine and carbohydrate during intense exercise in hypoxia similar to 4500 m can attenuate the increase in RPE by the increase in glycemia and can be a useful strategy for people who exercise in these conditions.
The aim of this study was to evaluate the combined effects of carbohydrate (CHO) and glutamine (Gln) supplementation on cytokine production by monocytes after exercise until exhaustion performed in ...hypoxia.
Fifteen physically active men underwent three exercises until exhaustion with an intensity of 70% maximal oxygen intake at a simulated height of 4500 m under the following supplementation: placebo, CHO (maltodextrin 8%/200 mL for 20 min), and CHO + Gln (Gln 20 g/d for 6 d and maltodextrin 8%/200 mL for 20 min) during exercise and for 2 h of recovery. Analysis of variance for repeated measures followed by the Tukey's post hoc test was realized and P < 0.05 was considered statistically significant.
Oxygen saturation of arterial blood (SaO2%) decreased in the three trials compared with baseline. Two hours post-exercise, the SaO2% was high in CHO + Gln condition compared with placebo. Two hours after exercise, interleukin (IL)-1β decreased compared with post-exercise in placebo and was lower compared with baseline in the CHO + Gln condition. Tumor necrosis factor-α decreased 2 h after exercise compared with baseline and pre-exercise in the CHO + Gln condition. No changes were observed in myeloperoxidase or IL-6 production. Two hours after exercise, Gln decreased compared with baseline and post-exercise in placebo and decreased 2 h after exercise in relation to post-exercise in the CHO condition. Gln increased post-exercise compared with pre-exercise in the CHO + Gln condition. Although erythropoietin did not change in this condition, it was high post-exercise and 2 h after exercise in the placebo condition compared with baseline and 2 h after exercise compared with baseline and pre-exercise in the CHO condition.
Gln supplementation for 6 d before exercise, associated with CHO supplementation during exercise, was able to revert Gln reduction after exercise and after 2 h of recovery and may have contributed to reducing tumor necrosis factor-α production, suggesting a possible anti-inflammatory effect of supplementation.
•Carbohydrate + glutamine supplementation increased oxygen saturation of arterial blood after exercise in hypoxia.•Carbohydrate + glutamine supplementation reduced the production of interleukin-1 by monocytes.•Carbohydrate + glutamine supplementation reduced the production of tumor necrosis factor-α by monocytes.
High altitudes are a challenge for human physiology and for sports enthusiasts. Several reasons lead to deterioration in performance at high altitudes. Hypoxia owing to high altitude causes a ...breakdown of homeostasis with imbalance in several physiological systems, including the immune system. The reduction in mucosal immunity and inflammation and the predominance of the humoral immune response causes a condition of immunosuppression and an increased likelihood of infection. In addition, it is known that worsening of the immune response is associated with reduced performance. On the other hand, immunonutrition plays an important role in modulating the effects of physical exercise on the immune system. However, to our knowledge, few studies have evaluated the effect of nutrition on the immune system after exercise in hypoxia. Although the association between exercise and hypoxia has been shown to be more severe for the body owing to the sum of stressful agents, supplementation with carbohydrates and glutamine seems to play a relevant role in mitigating immunosuppressive effects. These findings, although limited by the fact that they are the result of very few studies, shed light on a relevant theme for sports physiology and nutrition and suggest that both supplements may be useful for athletes, visitors, and workers in high-altitude regions. The aim of this review was to discuss the effects of high-altitude hypoxia on the human body from the point of view of exercise immunology because it is known that transient immunosuppression after strenuous exercise and competition should be followed by reduction in training overload and worse performance.
Introduction and objective
Moderate exercise performed in normoxia can be immunostimulatory, while strenuous exercise can be immunosuppressive. However, less is known about the effects of exercise ...under hypoxia on cytokines. The aim of this study was to evaluate the effects of an acute exercise session performed under hypoxia similar to an altitude of 4200 m on cytokine balance. Our hypothesis was that exercise, even of moderate intensity, associated with hypoxia may induce different changes in relation to the normoxic condition.
Methods
Eight healthy male volunteers were exercised on a treadmill for 1 hour at an intensity of 50% VO2peak under normoxic or hypoxic condition (4200 m). Blood samples were collected at rest and immediately 1 hour after the exercise, respectively to determine cytokines, hormones and metabolites. The two‐way ANOVA and the Bonferroni post hoc test were used and the significance adopted was P < .05.
Results
While IL‐2, the IL‐2/IL‐4 ratio and glutamine decreased under hypoxia, IL‐6 and IL‐1ra increased. There were increases in the IL‐2/IL‐4 ratio, IL‐6, IL‐1ra and IL‐10/TNF‐α in normoxia. There were no differences in cortisol or glucose.
Conclusion
Moderate exercise under hypoxia condition changes the Th1/Th2 balance including IL‐2, IL‐4 and TNF‐α cytokines, suggesting a Th2 response after 1 hour rest.
The present study aims first to compare the antioxidant microconstituent contents between organically and conventionally grown tomatoes and, second, to evaluate whether the consumption of purees made ...of these tomatoes can differently affect the plasma levels of antioxidant microconstituents in humans. When results were expressed as fresh matter, organic tomatoes had higher vitamin C, carotenoids, and polyphenol contents (except for chlorogenic acid) than conventional tomatoes. When results were expressed as dry matter, no significant difference was found for lycopene and naringenin. In tomato purees, no difference in carotenoid content was found between the two modes of culture, whereas the concentrations of vitamin C and polyphenols remained higher in purees made out of organic tomatoes. For the nutritional intervention, no significant difference (after 3 weeks of consumption of 96 g/day of tomato puree) was found between the two purees with regard to their ability to affect the plasma levels of the two major antioxidants, vitamin C and lycopene. Keywords: Organic cultural practices; tomatoes (Lycopersicon esculentum); lycopene; β-carotene; vitamin C; polyphenols
We aimed to assess whether longer indwelling time of peripherally inserted central catheters (PICC) increases risk of central line associated bloodstream infections (CLABSI) in haematology patients.
...Multicentre retrospective cohort study among haematology patients receiving PICCs between 2013 and 2015. Occurrence of CLABSI based on CDC definitions was assessed. We calculated incidence rates, determined risk factors for CLABSI and used Poisson regression models to assess the risk of developing CLABSI as a function of PICC dwell time. We compared diagnoses and treatment characteristics between 2013-2015 and 2015-2020.
455 PICCs placed in 370 patients were included, comprising 19,063 catheter days. Median indwelling time was 26 days (range 0-385) and CLABSI incidence was 4.0 per 1000 catheter days, with a median time to CLABSI of 33 days (range 18-158). Aplastic anaemia (AA) was associated with an increased risk of CLABSI; patients undergoing autologous stem cell transplantation (SCT) were less likely to develop CLABSI. In the unadjusted analysis, PICCs with an indwelling time of 15-28 days, 29-42 days, 43-56 days and > 56 days each had an increased CLABSI incidence rate ratio of 2.4 (1.2-4.8), 2.2 (0.95-5.0), 3.4 (1.6-7.5) and 1.7 (0.9-3.5), respectively, compared to PICCs in place for < 15 days. However, after adjusting for AA and SCT, there was no significant difference in incidence rates between dwell times (p 0.067).
Our study shows that risk of CLABSI does not appear to increase with longer PICC indwelling time. Routine replacement of PICCs therefore is unlikely to prevent CLABSI in this population.
Abstract Objective The aim of this study was to evaluate the effect of carbohydrate or glutamine supplementation, or a combination of the two, on the immune system and inflammatory parameters after ...exercise in simulated hypoxic conditions at 4500 m. Methods Nine men underwent three sessions of exercise at 70% VO2peak until exhaustion as follows: 1) hypoxia with a placebo; 2) hypoxia with 8% maltodextrin (200 mL/20 min) during exercise and for 2 h after; and 3) hypoxia after 6 d of glutamine supplementation (20 g/d) and supplementation with 8% maltodextrin (200 mL/20 min) during exercise and for 2 h after. All procedures were randomized and double blind. Blood was collected at rest, immediately before exercise, after the completion of exercise, and 2 h after recovery. Glutamine, cortisol, cytokines, glucose, heat shock protein-70, and erythropoietin were measured in serum, and the cytokine production from lymphocytes was measured. Results Erythropoietin and interleukin (IL)-6 increased after exercise in the hypoxia group compared with baseline. IL-6 was higher in the hypoxia group than pre-exercise after exercise and after 2 h recovery. Cortisol did not change, whereas glucose was elevated post-exercise in the three groups compared with baseline and pre-exercise. Glutamine increased in the hypoxia + carbohydrate + glutamine group after exercise compared with baseline. Heat shock protein-70 increased post-exercise compared with baseline and pre-exercise and after recovery compared with pre-exercise, in the hypoxia + carbohydrate group. No difference was observed in IL-2 and IL-6 production from lymphocytes. IL-4 was reduced in the supplemented groups. Conclusion Carbohydrate or glutamine supplementation shifts the T helper (Th)1/Th2 balance toward Th1 responses after exercise at a simulated altitude of 4500 m. The nutritional strategies increased in IL-6, suggesting an important anti-inflammatory effect.
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