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Lifelong amateur endurance practice attenuates oxidative stress and prevents muscle wasting in senior adults.

BACKGROUND
The aim of the study was to investigate oxidative stress, muscle damage, enzymatic antioxidant defense and body composition in senior adults who have performed different lifelong physical activity practices.


METHODS
Twenty-three healthy senior men (60±1.88 years old) were divided into three groups according to their lifelong physical activity practice as follows: A) sedentary (N.=7); B) recreational (N.=9); and C) amateur (N.=7). Blood sampling was performed at rest to analyze plasma malondialdehyde (MDA) by TBARs-assay, nuclear DNA-damage in peripheral lymphocytes using Comet-Assay, the plasma enzymatic activity of glutathione peroxidase by spectrophotometry and serum alpha-actin release as skeletal muscle damage marker through western blot. Body composition was evaluated using anthropometric assessments by the ISAK protocol through skinfold thickness.


RESULTS
The lowest value of MDA was shown in the amateur group. Nuclear DNA-damage was significantly lower in the recreational group than in sedentary and amateur groups (MD=5.53±1.70; P=0.013. MD=5.61±1.62; P=0.008), respectively. The amateur group showed trends toward higher glutathione peroxidase enzymatic activity than recreational and sedentary groups. Alpha-actin levels were significantly higher in the amateur compared with recreational (MD=4.34±0.46; P<0.001) and sedentary groups (MD=4.89±0.46; P<0.001). The sedentary group showed significantly lower muscle mass (MD=3.67±1.10; P=0.011) and higher fat mass (MD=4.19±0.98; P=0.001) than amateur group.


CONCLUSIONS
The results described above suggest that the lifelong amateur endurance practice seems to improve oxidative stress response and strengthens hypertrophy mechanisms that might preserve muscle mass in senior adults.