RESUMO
Physical activity results in oxidative stress, as evidenced by the increased production of reactive oxygen, nitrogen species, and inflammatory mediators. The management of these components is instrumental for antioxidant adaptation to exercise and post-exercise recovery. Therefore, the present report aims to study the antioxidant response to two types of exercise (a 2000 m run and a burpee test) in healthy volunteers after a long period of inactivity (1-2 months). Antioxidant enzyme activities and oxidative stress markers (protein carbonyls and malondialdehyde content) were measured in neutrophils, peripheral blood mononuclear cells, and plasma. These parameters were determined under basal conditions and immediately post-exercise. Compared to those in basal state, neutrophil superoxide dismutase (28.3 vs. 22.9 pkat/109 cells), glutathione peroxidase (147.5 vs. 120.1 nkat/109 cells), and catalase (106.3 vs. 57.9 k/109 cells) were activated significantly (p < 0.05) after the burpee test. Peripheral blood mononuclear cells exhibited only significant (p < 0.05) catalase activation (113.6 vs. 89.4 k/109 cells) after the burpee test. Other enzymes, such as glutathione reductase and myeloperoxidase, tended to increase post-exercise, although the differences from baseline were not significant. Finally, compared to basal conditions, the protein carbonyl (24.5 vs. 14.5 mmol/L) and malondialdehyde (39.6 vs. 18.3 mmol/L) contents increased significantly (p < 0.05) in neutrophils and in plasma (115.1 vs. 97.8 and 130.2 vs. 123.4 µmol/L, respectively) after the burpee test. In conclusion, high-intensity exercise seems to induce immediate oxidative stress in inactive individuals, and the acute antioxidant response was slightly greater after the burpee test than after the 2000 m run. Glutathione-dependent antioxidant systems are activated immediately as protective mechanisms.
RESUMO
BACKGROUND: Aging is a multifactorial physiological phenomenon, in which a series of changes in the body composition occur, such as a decrease in muscle mass and bone mineral density and an increase in fat mass. This study aimed to determine the relationship of muscle mass, osteoporosis, and obesity with the strength and functional capacity of non-dependent people over 70 years of age. METHODS: A cross-sectional study was designed, whose study population was all people aged over 70 years, living independently and attending academic and recreational programs. Muscle strength and functional capacity of the participants were assessed by isometric exercises of lower and upper limbs and by four tests taken from the Senior Fitness Test, respectively. Bone mineral density, total mass, fat mass, total lean mass, arms lean mass, legs lean mass, and appendicular lean mass (ALM) was calculated by dual energy X-ray absorptiometry. Differences in muscle strength and functional capacity, according to the sex, muscle mass, mineral bone density and fat mass, were measured by χ2 test, independent samples Student's t-test, analysis of covariance and a 2-factor analysis of covariance; Results: 143 subjects were included in the study group. Men and women with an adequate amount of ALM adjusted for body mass index (BMI) had a maximal dynamic biceps strength in a single repetition, a maximal isometric leg extension strength, a maximal dynamic leg extension strength in a single repetition, a maximum right hand grip strength and maximum hand grip strength (the highest). Significantly higher values were observed in the maximal isometric biceps' strength in men with osteoporosis. Obese men had less isometric strength in the biceps and took longer to perform the chair stand test; Conclusions: Men and women with an adequate amount of ALM adjusted for BMI obtained better results in tests of muscle strength and functional capacity. However, osteoporosis and obesity are not related to these parameters.