Higher levels of erythrocyte membrane fluidity in sprinters and long-distance runners

Red Blood Cell Distribution Width, Erythrocyte Indices, and Elongation Index at Baseline in a Group of Trained Subjects

BACKGROUND

Regular exercise elicits adaptive changes in several organs and physiological processes, including erythrocyte properties.

METHODS

In a group of 79 subjects (62 men and 17 women; mean age 31.37 ± 10.19 years) who trained several times a week as they practiced amateur sports, we evaluated the elongation index, markers of erythrocyte deformability, red blood cell distribution width (RDW), indicators of erythrocyte anisocytosis, hematocrit, hemoglobin, and the main erythrocyte indices (MCV, MCH, MCHC) in basal conditions.

RESULTS

In comparison with a group of healthy, but not training, volunteers, the values of the elongation index, and not the RDW, are increased, and this datum is accompanied by an increase in MCV and MCHC, likely related to an increased presence of circulating young erythrocytes in training subjects. We also divided the same group according to the median of the VO2max, observing that the subgroup above the median shows both an increase in the elongation index values and a decrease in MCH and MCHC.

CONCLUSIONS

In trained subjects, there is no correlation between the values of the elongation index and the RDW, while the interrelations among the elongation index, RDW, and main erythrocyte indices appear to be of particular interest and of a certain complexity.

ISSFAL Official Statement Number 6: The importance of measuring blood omega-3 long chain polyunsaturated fatty acid levels in research

A statement on measuring blood omega-3 long chain polyunsaturated fatty acid levels was developed and edited based on input from ISSFAL members and accepted by vote of the ISSFAL Board of Directors. Summary of Statement: Omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) levels at baseline and post-intervention should be assessed and reported in future research to evaluate the efficacy of n-3 LCPUFA supplementation: b ecause; 1. there are numerous factors that affect n-3 LCPUFA levels in humans as described in the systematic literature review [1]; 2. assessing intake of n-3 LCPUFA from the diet and/or supplements is not sufficient to accurately determine n-3 LCPUFA levels in humans; 3. some studies do not provide sufficient doses of n-3 LCPUFA to produce a significant impact on bloodstream/organ content and there is substantial variability in the uptake of n-3 LPCUFA into tissues between individuals. In secondary analyses, clinical trials should consider the influence of fatty acid status (baseline, endpoint and change from baseline to endpoint) on the outcome variables.

Non-dietary factors associated with n-3 long-chain PUFA levels in humans - a systematic literature review

Numerous health benefits are attributed to the n-3 long-chain PUFA (n-3 LCPUFA); EPA and DHA. A systematic literature review was conducted to investigate factors, other than diet, that are associated with the n-3 LCPUFA levels. The inclusion criteria were papers written in English, carried out in adult non-pregnant humans, n-3 LCPUFA measured in blood or tissue, data from cross-sectional studies, or baseline data from intervention studies. The search revealed 5076 unique articles of which seventy were included in the qualitative synthesis. Three main groups of factors potentially associated with n-3 LCPUFA levels were identified: (1) unmodifiable factors (sex, genetics, age), (2) modifiable factors (body size, physical activity, alcohol, smoking) and (3) bioavailability factors (chemically bound form of supplements, krill oil v. fish oil, and conversion of plant-derived α-linolenic acid (ALA) to n-3 LCPUFA). Results showed that factors positively associated with n-3 LCPUFA levels were age, female sex (women younger than 50 years), wine consumption and the TAG form. Factors negatively associated with n-3 LCPUFA levels were genetics, BMI (if erythrocyte EPA and DHA levels are <5·6 %) and smoking. The evidence for girth, physical activity and krill oil v. fish oil associated with n-3 LCPUFA levels is inconclusive. There is also evidence that higher ALA consumption leads to increased levels of EPA but not DHA. In conclusion, sex, age, BMI, alcohol consumption, smoking and the form of n-3 LCPUFA are all factors that need to be taken into account in n-3 LCPUFA research.

Deformability of different red blood cell populations and viscosity of differently trained young men in response to intensive and moderate running

BACKGROUND

Red blood cell (RBC) deformability and blood viscosity are essential to ensure optimal microcirculation and may contribute to athletic performance.

OBJECTIVE

To investigate the acute responses of density fractionated young, middle old and old RBC, RBC viscosity (RBCV), plasma viscosity (PV) and hematological changes to two running modes (intensive and moderate).

METHODS

27 young and healthy men of different training status participated in this study and were grouped into three groups in accordance to their VO2peak and conducted an intensive and moderate running test, respectively (crossover design). Pre and Post exercise, RBC were fractionated via percoll density gradient centrifugation. RBC deformability of the entire RBC population and the fractionated RBC was determined. Viscosity, hematocrit and mean cellular volume were determined.

RESULTS

Baseline results reveal that high trained subjects possess more young RBC and show increased deformability of un-fractioned RBC and middle aged RBC. Baseline PV, RBCV, hematocrit and mean cellular volume did not differ between groups. Applied running modes did not change RBC deformability of any sub-fractions. Viscosity only increased after intensive running. Hematological changes were observed after both exercises.

CONCLUSIONS

Acute effects of exercise on RBC are marginal, but chronic differences can be observed in RBC function.

Squeezing for Life - Properties of Red Blood Cell Deformability

Deformability is an essential feature of blood cells (RBCs) that enables them to travel through even the smallest capillaries of the human body. Deformability is a function of (i) structural elements of cytoskeletal proteins, (ii) processes controlling intracellular ion and water handling and (iii) membrane surface-to-volume ratio. All these factors may be altered in various forms of hereditary hemolytic anemia, such as sickle cell disease, thalassemia, hereditary spherocytosis and hereditary xerocytosis. Although mutations are known as the primary causes of these congenital anemias, little is known about the resulting secondary processes that affect RBC deformability (such as secondary changes in RBC hydration, membrane protein phosphorylation, and RBC vesiculation). These secondary processes could, however, play an important role in the premature removal of the aberrant RBCs by the spleen. Altered RBC deformability could contribute to disease pathophysiology in various disorders of the RBC. Here we review the current knowledge on RBC deformability in different forms of hereditary hemolytic anemia and describe secondary mechanisms involved in RBC deformability.

Impact of training volume and intensity on RBC-NOS/NO pathway and endurance capacity

BACKGROUND

Acute exercise increases red blood cell-nitric oxide synthase (RBC-NOS) activation and RBC deformability but the effect of regular training remains unclear.

OBJECTIVE

To detect the chronic effect of enduring moderate and high intensity training on the RBC-NOS/NO pathway and to detect a relation between RBC deformability and endurance capacity.

METHODS

38 healthy male subjects were randomly assigned to one of three training groups: High Volume Training (HVT; 120-140 beats per minute (bpm)), High Intensity Training (HIT; 160-180 bpm) and Moderate Intensity Training (MIT; 140-160 bpm). Blood parameters, maximum oxygen capacity (VO2 max), RBC deformability, RBC nitrite level and RBC-NOS activation were measured after venous blood sampling at rest pre (T0) and after six weeks of training (T1).

RESULTS

RBC-NOS activation, RBC nitrite concentration and RBC deformability were significantly increased at T1 in the HIT group. Parameters were unaltered in MIT and HVT. Maximum oxygen uptake was only significantly increased in the HIT group and regression analysis revealed positive regression between VO2 max and RBC deformability.

CONCLUSIONS

High intensity training was the only training programme that sustainably affected RBC-NOS dependent NO production and performance capacity. HIT therefore represents a time efficient training program resulting in improved RBC function potentially improving physical condition.

Erythrocytes and Skeletal Muscle Unsaturated and Omega-6 Fatty Acids Are Positively Correlated after Caloric Restriction and Exercise

BACKGROUND

Nutritional intervention studies with fatty acid (FA) supplements assess the efficacy of the intervention by measuring the changes in erythrocyte membrane lipid profiles reflected in tissue composition changes. The aim was to determine the effects of caloric restriction (CR) on erythrocytes lipid composition and to compare and correlate these changes with skeletal muscle acid profiles after CR.

METHODS

Erythrocytes were obtained from 11 healthy men before and after 4 weeks of 33% CR in post-exercise conditions; muscle biopsies were obtained from the same athletes after 4 weeks of 33% CR in post-exercise conditions. Samples were used for FA determination by chromatography.

RESULTS

CR significantly modified erythrocyte FAs composition. Skeletal muscle FA profile was significantly different from that for the erythrocytes. The erythrocyte FA profile was more saturated (52.1 ± 1.5% and 32.8 ± 0.9%, respectively) and less monounsaturated (21.0 ± 0.8% and 39.0 ± 2.0%, respectively) than the skeletal muscle FA profile and similarly polyunsaturated.

CONCLUSIONS

CR modifies erythrocyte lipid composition, mainly omega-6 FAs. Erythrocyte monounsaturated, polyunsaturated and omega-6 FAs, but not the saturated and omega-3 FAs, were significantly positively correlated with skeletal muscle FAs. There is a discordance between saturated and omega-3 FAs from erythrocyte and from muscle, but monounsaturated, polyunsaturated and omega-6 fatty acids are positively correlated.

Effects of acute and chronic exercise on the osmotic stability of erythrocyte membrane of competitive swimmers

This study aimed to evaluate the influence of acute and chronic exercise on erythrocyte membrane stability and various blood indices in a population consisting of five national-level male swimmers, over 18 weeks of training. The evaluations were made at the beginning and end of the 1st, 7th, 13th and 18th weeks, when volume and training intensity have changed. The effects manifested at the beginning of those weeks were considered due to chronic adaptations, while the effects observed at the end of the weeks were considered due to acute manifestations of the exercise load of that week. Acute changes resulting from the exercise comprised increases in creatine kinase activity (CK) and leukocyte count (Leu), and decrease in hematocrit (Ht) and mean corpuscular volume (MCV), at the end of the first week; increase in the activities of CK and lactate dehydrogenase (LDH), in the uric acid (UA) concentration and Leu count, at the end of the seventh week; increases in CK and LDH activities and in the mean corpuscular hemoglobin concentration (MCHC), at the end of the 13th week; and decrease in the value of the osmotic stability index 1/H₅₀ and increases in the CK activity and platelets (Plt) count, at the end of the 18th week. Chronic changes due to training comprised increase in the values of 1/H₅₀, CK, LDH, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum iron (Fe), MCV and Plt. Although acute training has resulted in decrease in the osmotic stability of erythrocytes, possibly associated with exacerbation of the oxidative processes during intense exercise, chronic training over 18 weeks resulted in increased osmotic stability of erythrocytes, possibly by modulation in the membrane cholesterol content by low and high density lipoproteins.

Docosahexaenoic acid supplementation promotes erythrocyte antioxidant defense and reduces protein nitrosative damage in male athletes

The aim of this study was to determine the influence of long-term docosahexaenoic acid (DHA) dietary supplementation on the erythrocyte fatty acid profile and oxidative balance in soccer players after training and acute exercise. Fifteen volunteer male athletes (age 20.0 ± 0.5 years) were randomly assigned to a placebo group that consumed an almond-based beverage (n = 6), or to an experimental group that consumed the same beverage enriched with DHA (n = 9) for 8 weeks. Blood samples were taken in resting conditions at the beginning and after 8 weeks of nutritional intervention and training in resting and in post-exercise conditions. Oxidative damage markers (malonyldialdehyde, carbonyl and nitrotyrosine indexes) and the activity and protein level of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase and peroxidase) were assessed. The results showed that training increased antioxidant enzyme activities in erythrocytes. The experimental beverage increased DHA from 34.0 ± 3.6 to 43.0 ± 3.6 nmol/10(9) erythrocytes. DHA supplementation increased the catalytic activity of superoxide dismutase from 1.48 ± 0.40 to 10.5 ± 0.35 pkat/10(9) erythrocytes, and brought about a reduction in peroxidative damage induced by training or exercise. In conclusion, dietary supplementation with DHA changed the erythrocyte membrane composition, provided antioxidant defense and reduced protein peroxidative damage in the red blood cells of professional athletes after an 8-week training season and acute exercise.

Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells

During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O₂ from the lungs to the tissues and the delivery of metabolically produced CO₂ to the lungs for expiration. Hemoglobin also contributes to the blood's buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called “sports anemia.” This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise.

Altered plasma and erythrocyte phospholipid fatty acid profile in elite female water polo and football players

The impact of chronic, intense exercise, such as in elite athletes, on phospholipids fatty acids (FA) composition has not been studied in women so far. This study aimed to investigate FA profiles in plasma and erythrocytes phospholipids in elite female water polo (N = 15) and football (N = 19) players in comparison with sedentary women. In spite of similar dietary patterns, as assessed by a food frequency questionnaire, plasma FA profile in the football players showed significantly higher proportions of stearic acid, oleic acid, and monounsaturated FA (MUFA), and significantly lower proportions of total and n-6 polyunsaturated FA (PUFA) than in the water polo and control group. The water polo players had higher percentages of palmitoleic acid and arachidonic acid than the control subjects. Erythrocyte FA profile differed among groups. We found significantly higher proportion of oleic acid and MUFA in the football group than in the controls, and decreased stearic acid and elevated palmitic and palmitoleic acid in the water polo players than in the other 2 groups. Both groups of athletes had significantly lower percentages of n-6 dihomo-γ-linolenic acid, n-6 PUFA, and total PUFA compared with the controls. The estimated activities of elongase and desaturases in erythrocytes were also altered in the athletes. Our results indicate that long-term, intense physical training significantly affects FA status of plasma and erythrocyte phospholipids in women. The observed differences between the water polo and the football players suggest that the type of regular training may contribute to the altered metabolism of FA, although possible genetic differences among the 3 study groups cannot be ruled out.

Unfavourable plasma and erythrocyte phospholipid fatty acid profile in elite amateur boxers

Research on possible physiological changes as a consequence of a specific lifestyle and long-term strenuous exercise in boxing has been sparse. We determined plasma and erythrocyte phospholipid (PL) fatty acids (FA) profile of 16 elite amateur male boxers (22.4±3.3 years of age), and compared them with a control group composed of 19 sedentary (24.4±3.4) year-old men. The percentages of total saturated fatty acids (SFA) and monosaturated FA in plasma phospholipids were significantly higher (P <0.001) in boxers compared to the control group. On the other hand, all studied polyunsaturated fatty acids (PUFA) in plasma PL with the exception of eicosapentaenoic acid (EPA, 20:5, n-3) and docosatetraenoic acid (DTA, 22:4, n-6) were significantly lower in boxers than in sedentary men. Total PUFA, n-6 PUFA and n-3 PUFA were also significantly lower in boxers (P <0.001), whereas the n-6/n-3 ratio was higher in boxers than in control group (P <0.01). Boxers had significantly higher proportion of all SFA in erythrocyte PL compared to the control group (P <0.05). In addition, the percentage of linoleic acid was lower in boxers' erythrocyte PL than in the control group (P <0.05). The results show two potentially unfavourable main features of the FA profile of boxers, that is, a higher n-6/n-3 ratio in plasma PL and a higher percentage of SFA in both plasma and erythrocyte phospholipids compared to controls. As SFA correlates directly with the incidence of cardiovascular disease and high n-6/n-3 ratio has been shown to stimulate carcinogenesis and modulate inflammation and autoimmunity, this profile could be detrimental to the health of boxers. The mechanism underlying these differences requires further investigation; however the results suggest benefits of nutritional intervention.

The effects of dietary N-3 and antioxidant supplementation on erythrocyte membrane fatty acid composition and fluidity in exercising horses

REASONS FOR PERFORMING STUDY

Fatty acid supplementation could modulate erythrocyte membrane fluidity in horses at rest and during exercise, but information is lacking on the effect of exercise.

OBJECTIVES

To assess the effect of exercise with, and without, an oral antioxidant supplementation enriched with n-3 fatty acids on erythrocyte membrane fluidity (EMF) and fatty acid composition in eventing horses.

METHODS

Twelve healthy and regularly trained horses were divided randomly into 2 groups: group S received an oral antioxidant cocktail enriched in n-3 fatty acid (alphatocopherol, eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) whereas group P was placebo-treated. At the end of 4 weeks, all horses performed a standardised exercise test (ET) under field conditions. Venous blood was sampled before starting treatment (TO), immediately before (T1) as well as 15 min (T2) and 24 h (T3) after ET. Spin labelled (16-DOXYL-stearic acid) red blood cell membranes were characterised using the relaxation correlation time (Tc in inverse proportion to EMF). Fatty acid composition (%) of the membrane was determined by gas-liquid chromatography.

RESULTS

Supplementation did not induce changes in EMF (T1 vs. TO) but significant changes in membrane composition were observed and there were increases in n-3 polyunsaturated fatty acid PUFA, n-3/n-6 ratio, and total n-3 fatty acids. Exercise (T2 vs. T1) induced a significant decrease of EMF in group P (Tc: +19%, P<0.05) and nonsignificant decrease in group S (Tc: +5%), whereas membrane fatty acid composition did not change in either group. During the recovery period (T3 vs. T2), EMF decreased significantly in group S (Tc: +29%, P<0.05) and nonsignificantly in group P (Tc: +18%) without any significant changes in fatty acid composition.

CONCLUSION AND POTENTIAL RELEVANCE

An enriched oral antioxidant supplementation induced changes in membrane composition, which modulated the decrease in EMF induced by exercise. Long chain n-3 fatty acid supplementation might therefore be beneficial.

Plasma and erythrocyte phospholipid fatty acid profile in professional basketball and football players

The effect of intensive long-term physical activity on phospholipid fatty acid (FA) composition has not been studied thoroughly. We determined plasma and erythrocyte phospholipid FA status of professional basketball and football players. Our results showed differences in plasma FA profile not only between sportsmen and sedentary subjects, but also between two groups of sportsmen. Plasma FA profile in basketball players showed significantly higher proportion of n-6 FA (20:3, 20:4, and 22:4) and total polyunsaturated FA (PUFA) than controls, while football players had higher palmitoleic acid (16:1) than basketball players and controls. Total PUFA and 22:4 were also higher in basketball than in football players. Erythrocyte FA profile showed no differences between football players and controls. However, basketball players had higher proportion of 18:0 than controls, higher saturated FA and lower 18:2 than two other groups, and higher 22:4 than football players. These findings suggest that long-term intensive exercise and type of sport influence FA profile.

Erythrocyte deformability and nitric oxide metabolites in athletes before and after a cardiopulmonary test

OBJECTIVE

To evaluate erythrocyte deformability, nitric oxide metabolites, and their modifications induced by exercise in athletes who practised different sports.

DESIGN

This evaluation was effected before and after cardiopulmonary test, using a cycloergometer.

SETTING

The study was performed in the Department of Internal Medicine, Cardiovascular and Renal Diseases of the University of Palermo.

PARTICIPANTS

We enrolled 62 male athletes who practised endurance (n = 23), mixed (n = 20), and power (n = 19) sports and 20 sedentary male subjects as controls.

ASSESSMENT OF RISK FACTORS

No subject had diabetes or hypertension or dyslipidemia. Five control subjects and 14 athletes were smokers.

MAIN OUTCOME MEASURES

Erythrocyte deformability was examined as elongation index (EI) using a diffractometer. The nitric oxide metabolites (nitrite + nitrate = NOx) were evaluated employing the Griess reagent.

RESULTS

In the whole group, an increase in EI and NOx was present. Subdividing the whole group into 3 subgroups, we noted an increase in EI and NOx only in endurance and mixed athletes. The EI before and after the cardiopulmonary test significantly decreased in the whole group and in power athletes but not in endurance and mixed athletes. Before and after the test, NOx did not significantly change in the whole group and in the 3 subgroups.

CONCLUSIONS

In athletes who practised endurance and mixed sports, we observed an increase of NOx level and an increase of erythrocyte deformability. The latter did not change after an exercise test in the same subgroups, whereas it decreased in power athletes.

Docosahexaenoic acid in red blood cells of women of reproductive age is positively associated with oral contraceptive use and physical activity

Optimal intake of the long-chain n-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) and proper balance between intake of n-6 PUFA and n-3 PUFA are important for human health. Considerable evidence exists to show that DHA has a marked benefit during pregnancy. Lifestyle factors can affect the biosynthesis of DHA from dietary precursors, incorporation into membranes and degradation. The purpose of this study was to investigate the PUFA composition of red blood cells (RBCs) from women (n=40) in reproductive age, and how it is affected by diet and other lifestyle factors. Of all the lifestyle factors tested oral contraceptive use and physical activity were the ones correlated with DHA in RBCs, after adjustment for DHA intake. The findings indicate that oral contraceptive use and physical activity have a positive impact on the DHA status, as assessed by RBC level, of women in reproductive age.

Effects of exercise on the fatty-acid composition of blood and tissue lipids

This article reviews the effects of acute and chronic exercise on the fatty-acid composition of animal and human tissues (plasma, skeletal muscle, heart, adipose tissue, liver, artery and erythrocytes), as reported in 68 studies spanning four decades. The most consistently observed effect has been an increase in the relative amount of unsaturated, especially monounsaturated, non-esterified fatty acids in plasma of both animals and humans after acute exercise. Chronic exercise seems to increase the proportion of polyunsaturated fatty acids and omega6 fatty acids, while decreasing the proportion of monounsaturated fatty acids in animal and human adipose tissue. Additionally, chronic exercise seems to decrease the relative amount of unsaturated fatty acids in liver lipids of animals and humans. There is no consensus regarding the effect of exercise on the fatty-acid composition of lipids in any other tissue. In general, the effects of exercise are independent of nutrition and, regarding skeletal muscle, muscle fibre type. The available literature shows that, in addition to modifying the concentrations of animal and human tissue lipids, exercise also changes their fatty-acid profile. Unfortunately, the available studies are so much divided among exercise models, species and biological samples that a cohesive picture of the plasticity of the fatty-acid pattern of most tissues toward exercise has not emerged. Future studies should focus on determining the fatty-acid profile of separate lipid classes (rather than total lipids) in separate subcellular fractions (rather than whole tissues), examining tissues and organs on which no data are available and exploring the mechanisms of the exercise-induced changes in fatty-acid composition.

Greater erythrocyte deformability in world-class endurance athletes

Because athletes during endurance events require rapid uptake of oxygen, the ability of red blood cells (RBC) to move through capillaries may limit performance. Using ektacytometry, we determined whether RBC deformability (RCD) differed between elite road cyclists (n = 9) and sedentary controls (n = 5). Density profiles and standard hematological measurements were also performed. The deformability index (DI) was higher in the cyclists (0.723 +/- 0.027) compared with that in controls (0.619 +/- 0.040, P < 0.001). Cyclists also had a larger percentage of low-density RBCs (P < 0. 001), and mean cell volume (MCV) was also higher (P = 0.013). These findings are indicative of a larger proportion of "young" RBCs in the blood of elite cyclists and provide further evidence that the turnover of RBCs in endurance athletes is higher than in the general population. With a younger more deformable RBC population and providing the destruction does not exceed replacement, performance potential should be enhanced. Furthermore, examination of factors that contribute to increased RBC turnover in athletes may help us understand the mechanisms that cause RBC aging.

Vitamins Q and E, extracorporal circulation and hemolysis

Whole blood vitamin Q (ubiquinone), plasma vitamins Q and E (alpha-(alpha-)tocopherol) and free cholesterol (FC) were studied before (control or base-line value, sample I) and during open chest surgery and extracorporal circulation (samples II-IV) in 10 male IHD patients. Identity existed between control whole blood and plasma ubiquinone. During surgery an increased discrepancy with lower plasma vitamin Q levels were seen. Control plasma vitamins Q, E and FC averaged 0.88 +/- 0.16 (SE), 12.1 +/- 2.2 mg x l(-1) and 0.75 +/- 0.15 g x l(-1). Corresponding molar values were 1.02 +/- 0.17, 28.1 +/- 5.1 micromol x l(-1) and 1.94 +/- 0.74 mmol x l(-1). Vitamin Q and E decreased continuously and averaged 0.64 mg x l(-1) in sample IV (0.74 micromol x l(-1), p < 0.001) and 9.4 mg x l(-1) in sample III (21.8 micromol x l(-1), p < 0.001). Hemolysis in all sample IV vials, ruined all vitamin E determinations. When normalized for FC (NQ and NE), decreases were found to be 17 (IV) and 12% (III), respectively. Large interindividual variations existed. High control NQ and NE values allowed a larger antioxidant vitamin depletion. High NQ seemed also to be a prerequisite for NE depletion. In addition, signs indicated an active liver vitamin Q release for patients rich in control antioxidant values. It was suggested that the antioxidant vitamin depletion did not prevent from radical trauma to membrane structural lipids (especially omega-3 fatty acids or vitamin F1), less membrane fluidity, erythrocyte fragility and hemolysis.

Exercise, training and red blood cell turnover

Endurance training can lead to what has been termed 'sports anaemia'. Although under normal conditions, red blood cells (RBCs) have a lifespan of about 120 days, the rate of aging may increase during intensive training. However, RBC deficiency is rare in athletes, and sports anaemia is probably due to an expanded plasma volume. Cycling, running and swimming have been shown to cause RBC damage. While most investigators measure indices of haemolysis (for example, plasma haemoglobin or haptoglobin), RBC removal is normally an extravascular process that does not involve haemolysis. Attention is now turning to cellular indices (such as antioxidant depletion, or protein or lipid damage) that may be more indicative of exercise-induced damage. RBCs are vulnerable to oxidative damage because of their continuous exposure to oxygen and their high concentrations of polyunsaturated fatty acids and haem iron. As oxidative stress may be proportional to oxygen uptake, it is not surprising that antioxidants in muscle, liver and RBCs can be depleted during exercise. Oxidative damage to RBCs can also perturb ionic homeostasis and facilitate cellular dehydration. These changes impair RBC deformability which can, in turn, impede the passage of RBCs through the microcirculation. This may lead to hypoxia in working muscle during single episodes of exercise and possibly an increased rate of RBC destruction with long term exercise. Providing RBC destruction does not exceed the rate of RBC production, no detrimental effect to athletic performance should occur. An increased rate of RBC turnover may be advantageous because young cells are more efficient in transporting oxygen. Because most techniques examine the RBC population as a whole, more sophisticated methods which analyse cells individually are required to determine the mechanisms involved in exercise-induced damage of RBCs.

Exercise-induced hypoxaemia in master athletes: effects of a polyunsaturated fatty acid diet

Exercise-induced hypoxaemia (EIH) has been associated with an oxygen diffusion limitation. Because polyunsaturated fatty acids (PUFA) administration can modify cell membrane fluidity, we hypothesized that the importance of EIH could be reduced after a 6-week PUFA diet. Resting pulmonary functions and a maximal cycling test were performed before and after the diet, in eight master athletes -48 (SD 6 years)-. The partial pressure of O2 in arterial blood (PaO2), alveolar ventilation (VA) and ideal alveolar-arterial oxygen partial pressure difference (P(Ai-a) O2) were obtained at each exercise intensity. The extent of EIH at maximal exercise was significantly lower after PUFA [PaO2-17.2 (SEM 1.9) vs -12.9 (SEM 2.2)]. Before PUFA, VA accounted for 50% of the variance in the fall in P (Ai-a) for intensities below 80% maximal oxygen uptake (VO2max) and P(Ai-a)O2 for 60% between 70% and 100% VO2max. After PUFA, the reduction in EIH was highly correlated (r2 = 0.85; P < 0.001) to resulting changes in P(Ai-a)O2 and resting pulmonary diffusing capacity (DLCO)/VA but not with changes in ideal alveolar partial pressure of oxygen. The improvement in EIH following PUFA could be related to an increase in alveolar-arterial oxygen conductance following improved pulmonary diffusion.