A lifelong competitive training practice attenuates age-related lipid peroxidation

The effect of exercise-induced oxidative stress on health and aging is not clearly explained. This study examined the effects of habitual sport practice, age, and submaximal exercise on the blood markers of oxidative stress, muscle damage, and antioxidant response. Seventy-two healthy men were grouped by their habitual sport practice: inactive (<1.5 h/week), recreational (3-8 h/week), and trained athletes (>8 h/week), and further divided by age: young (18-25 years), adult (40-55 years), and senior (>55 years). Blood samples were collected at rest and after submaximal effort. Hydroperoxides and superoxide dismutase, glutathione peroxidase, and catalase activities were measured by spectrophotometry. Nuclear DNA damage was analyzed by comet assay. The alpha-actin release was analyzed by Western blot. Alpha-tocopherol, retinol, and coenzyme-Q10 were quantified by high-performance liquid chromatography analysis. Data was analyzed through a factorial ANOVA and the Bonferroni post hoc test. Lipid peroxidation increased significantly with age and submaximal effort (p < 0.05). However, the trained athlete group presented lower lipid peroxidation compared with the recreational group (MD = 2.079, SED = 0.58, p = 0.002) and inactive group (MD = 1.979, SED = 0.61, p = 0.005). Trained athletes showed significant higher alpha-actin levels (p < 0.001) than the other groups. Recreational group showed lower nuclear DNA damage than trained athletes (MD = 3.681, SED = 1.28, p = 0.015). Nevertheless, the inactive group presented significantly higher superoxide dismutase and catalase (p < 0.05) than the other groups. Data suggested that habitual competitive training practice could prevent age-related increases of plasma lipid peroxidation, which, according with our results, cannot be entirely attributed to blood antioxidant defense systems (AU)

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A lifelong competitive training practice attenuates age-related lipid peroxidation.

The effect of exercise-induced oxidative stress on health and aging is not clearly explained. This study examined the effects of habitual sport practice, age, and submaximal exercise on the blood markers of oxidative stress, muscle damage, and antioxidant response. Seventy-two healthy men were grouped by their habitual sport practice: inactive (<1.5 h/week), recreational (3-8 h/week), and trained athletes (>8 h/week), and further divided by age: young (18-25 years), adult (40-55 years), and senior (>55 years). Blood samples were collected at rest and after submaximal effort. Hydroperoxides and superoxide dismutase, glutathione peroxidase, and catalase activities were measured by spectrophotometry. Nuclear DNA damage was analyzed by comet assay. The alpha-actin release was analyzed by Western blot. Alpha-tocopherol, retinol, and coenzyme-Q10 were quantified by high-performance liquid chromatography analysis. Data was analyzed through a factorial ANOVA and the Bonferroni post hoc test. Lipid peroxidation increased significantly with age and submaximal effort (p < 0.05). However, the trained athlete group presented lower lipid peroxidation compared with the recreational group (MD = 2.079, SED = 0.58, p = 0.002) and inactive group (MD = 1.979, SED = 0.61, p = 0.005). Trained athletes showed significant higher alpha-actin levels (p < 0.001) than the other groups. Recreational group showed lower nuclear DNA damage than trained athletes (MD = 3.681, SED = 1.28, p = 0.015). Nevertheless, the inactive group presented significantly higher superoxide dismutase and catalase (p < 0.05) than the other groups. Data suggested that habitual competitive training practice could prevent age-related increases of plasma lipid peroxidation, which, according with our results, cannot be entirely attributed to blood antioxidant defense systems.

La exposición aguda a altitud previene el estrés oxidativo por una movilización del alfa-tocoferol plasmático / Acute exposure to moderate altitude prevents oxidative stress by a plasmatic alpha-tocopherol mobilization

Introducción: Existe gran controversia sobre el efecto de la hipoxia en el estatus oxidativo de deportistas; por otra parte, la mayoría de estudios analizan los mecanismos de adaptación tras un periodo de aclimatación y no contemplan el efecto de las exposiciones agudas. Así, nuestro estudio pretende comprobar el efecto del ejercicio y la exposición aguda a una altitud moderada sobre el estrés oxidativo en nadadores. Material y método: Diez nadadores entrenados (5 mujeres, 5 hombres) realizaron dos sesiones idénticas de entrenamiento de 90 minutos, una a 630 m (normoxia) y otra a 2320 m de altitud (hipoxia); ambas se ajustaron para generar valores de lactato ligeramente superiores al umbral anaeróbico. Se extrajeron 5 ml de sangre en reposo y tras el esfuerzo. Las muestras fueron centrifugadas para la obtención de plasma y congeladas a -80ºC. Como marcador de peroxidación lipídica se determinaron concentraciones de hidroperóxidos y sustancias reactivas al ácido tiobarbitúrico (TBARS). Como mecanismo antioxidante no enzimático se cuantificó el alfa-tocoferol. Las comparaciones de medias se realizaron con una ANOVA de un factor. Resultados: La exposición a hipoxia produjo un descenso significativo de TBARS (20,78±8,36 nmol/ml, p<0,03) y, tras el esfuerzo, de hidroperóxidos (20,78±8,36 nmol/ml, p<0,03) en hombres. En nadadores de ambos sexos, el alfa-tocoferol disminuyó significativamente debido a la hipoxia (hombres: 23,06±4,26 nmol/ml, mujeres: 19,51±4,26 nmol/ml, p<0,001). En normoxia, las mujeres presentaron menor concentración de TBARS (20,54±8,36 nmol/ml, p<0,03) e hidroperóxidos (2,16±0,87 nmol/ml, p<0,03) que los hombres. La sesión de entrenamiento no modificó dichas variables. Conclusiones: En estudios previos demostramos una movilización de antioxidantes no enzimáticos desde plasma a tejidos muscular y hepático en situaciones de estrés oxidativo. Concluimos que una exposición aguda a altitud moderada podría prevenir el estrés oxidativo en nadadores debido a una rápida movilización del alfa-tocoferol plasmático (AU)

Introduction: There is a controversy concerning to the modulation of hypoxia-induced oxidative stress; in addition, most studies covered mechanism of adaptation to altitude after an acclimation period, and they did not test the effects of acute exposures to hypoxia. Thus, the aim of the study was to establish oxidative status of trained swimmers analyzing the effects of exercise and acute exposure to moderate altitude. Materials and methods: Ten well-trained swimmers (5 females, 5 males) performed two similar mild-intensity training sessions of 90 minutes, one at an altitude of 630 m (normoxia) and the second of 2320 m (hypoxia). Training sessions were regulated to generate blood lactate values slightly higher than anaerobic threshold. 5 ml of blood samples were collected before and immediately after the exercise. Plasma were obtained by blood-centrifugation, samples were stored at -80ºC until analysis. Lipid peroxidation markers were hydroperoxides and thiobarbituric acid reactive substances (TBARS). Alpha-tocopherol was analyzed as non-enzymatic antioxidant mechanism. Comparisons between means were performed using one-way ANOVA. Results: Acute exposure to hypoxia produced a significant decrease of TBARS (20.78±8.36 nmol/ml, p<0.03) and, after effort, of hydroperoxides (20.78±8.36 nmol/ml, p<0.03) in men. In swimmers of both sexes, plasmatic alpha-tocopherol significantly decreased by hypoxia (men: 23.06±4.26 nmol/ml, women: 19.51±4.26 nmol/ml, p<0.001). In normoxia condition, women presented lower concentrations of TBARS (20.54±8.36 nmol/ml, p<0.03) and hydroperoxides (2.16±0.87 nmol/ml, p<0.03) than men. Mild-intensity training session did not modify oxidative stress in well-trained swimmers. Conclusions: In previous studies we demonstrated a non-enzymatic antioxidant mobilization from plasma to muscular and hepatic tissues as a response to an oxidative stress situation. Therefore, we conclude that acute exposure to moderate altitude could prevent oxidative stress in swimmers by a fast mobilization of plasmatic alpha-tocopherol (AU)

Effects of ultraviolet radiation and nutrients on the structure-function of phytoplankton in a high mountain lake.

The combined effect of high solar ultraviolet radiation (UVR) and nutrient supply in a phytoplankton community of a high mountain lake is analyzed in a in situ experiment for 6 days with 2 × 2 factorial design. Interactive UVR × nutrient effects on structural and functional variables (algal biomass, chlorophyll a (chl a), primary production (PP), maximal electron transport rate (ETR(max)), and alkaline phosphatase activity (APA)), as well as stoichiometric ones (sestonic N per cell and N:P ratio) were found. Under non-nutrient enriched conditions, no deleterious effects of UVR on structural variables, PP, photosynthetic efficiency and ETR(max) were observed, whereas only particulate and total APA were affected by UVR. However, percentage excreted organic carbon (%EOC), dissolved APA and sestonic C and P per cell increased under UVR, leading to a decrease in algal C:P and N:P ratios. After nutrient enrichment, chl a, total algal biomass and PP were negatively affected by UVR whereas %EOC, ETR(max) and internal C, P and N content increased. We suggest that the mechanism of algal acclimation to UVR in this high UVR flux ecosystem seems to be related to the increase of internal algal P-content mediated by physiological mechanisms to save P and by a stimulatory UVR effect on dissolved extracellular APA. The mechanism involved in the unmasking effect of UVR after nutrient-enrichment may be the result of a greater sensitivity to UVR-induced cell damage, making the negative UVR effects more evident.