Effect of vitamin E supplementation with exercise on cognitive functions and total antioxidant capacity in older people.

OBJECTIVE: We investigated the effects of six months vitamin E administration on cognition evaluated by event-related potentials in exercising older subjects. DESIGN: Randomised controlled trial. SETTING: Retirement home in Antalya, Turkey. PARTICIPANTS: Fifty-seven adults aged 60-85 years were randomly assigned to one of four groups: sedentary control (C), vitamin E (V), exercise training (E) and vitamin E under training (EV). INTERVENTION: V and EV groups were received vitamin E at a dose of 900 IU/day P.O. for 6 months. Trained groups were subjected to walking exercise involved 3 sessions per week for 6 months. Walking duration was gradually increased during 8 weeks, and stayed constant until the end of training period. Participants were begun walking at % 70 heart rate reserve for 20 min/day at the first two weeks, and walking duration was increased by 5 minutes/day of each week until subjects were reached a level of 50 min/day by week 8. MEASUREMENTS: Plasma vitamin E concentration, total antioxidant capacity and two parameters of event-related potentials namely P3 latency and amplitude were performed on all study groups both before and after training. RESULTS: Significant improvement in P3 latency was found in exercising groups. However, no significant differences were found between vitamin and other groups for P3 latency. Amplitude measurements were found unaltered among all groups. CONCLUSION: We concluded that although six months training results improvement in P3 latency, vitamin E supplementation does not affect cognitive function evaluated by event-related potentials in older subjects.

Training induced alterations of visual evoked potentials are not related to body temperature.

The purpose of this study was to investigate the effect of mild chronic exercise on visual evoked potentials (VEPs). Twenty male Wistar rats were randomly divided into two groups: Control (C) and Exercise (E) groups. Exercise was performed on a motor-driven treadmill for 8 weeks. After 5 min of exercise, plasma lactic acid levels were determined. At the end of the experimental period, VEPs were recorded from E group twice: Five min (E-5 min) and 24 h (E-24 h) after the last bout of exercise. During visual evoked potential (VEP) recordings body temperature of the animals was kept constant to eliminate the effect of temperature changes. No difference was found between the lactic acid levels of two groups. The mean latencies of VEPs from E-5 min were shortened compared with the control group. The mean latencies of VEP components in E-24 h were observed to have returned to the control levels. Peak to peak amplitudes of VEPs were found to be unaltered among all measurements. We concluded that immediately after exercise, VEPs latencies were shortened independently from body temperature via unknown mechanisms. The latencies of VEPs were returned to control values after 24 h.

The effect of exercise on brain antioxidant status of diabetic rats.

BACKGROUND: To investigate the effect of exercise on brain antioxidant status of diabetic rats. METHODS: Wistar rats were divided into four groups: Control (C), exercise (CE), diabetic (D), and diabetic+exercise (DE). Diabetes was induced by single administration of streptozotocin (60 mg/kg). We used an aerobic exercise program for 8 weeks of CE and DE rats. After the end of the experimental period, Cu, Zn-superoxide dismutase (Cu, Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), xanthine dehydrogenase (XDH) and xanthine oxidase (XO) activities and thiobarbituric acid reactive substances (TBARS) levels of brain were measured. RESULTS: Diabetes caused significant reduction of brain Cu, Zn-SOD and GSH-Px activities in the D and DE groups. CAT activity was decreased only in the D group. Exercise did not alter CAT activity of brain, whereas markedly increased Cu, Zn-SOD activity in the DE group. In contrast to diabetes-related decrease in the activity of Cu, Zn-SOD, increase in the XO and GSH-Px activities were observed in the DE group compared with the D group. XDH activity was significantly reduced in two exercise groups according to the control rats, but the decrease was not accompanied with the activity of XO elevation in all groups. Increase in the XO activity and decrease in the XDH activity in the DE rats have revealed that diabetes and exercise have potentially effect in free radical production. On the other hand, TBARS levels were found to be elevated in all diabetic animals. CONCLUSIONS: Our results show that aerobic exercise did not affect lipid peroxidation of brain, but in diabetic condition improved antioxidant defence.