Physical exercise in the prevention and treatment of Alzheimer’s disease

Dementia is one of the greatest global challenges for health and social care in the 21st century.Alzheimer’s disease(AD),the most common type of dementia,is by no means an inevitable consequence of growing old.Several lifestyle factors may increase,or reduce,an individual’s risk of developing AD.Much has been written over the ages about the benefits of exercise and physical activity.Among the risk factors associated with AD is a low level of physical activity.The relationship between physical and mental health was established several years ago.In this review,we discuss the role of exercise(aerobic and resistance)training as a therapeutic strategy for the treatment and prevention of AD.Older adults who exercise are more likely to maintain cognition.We address the main protective mechanism on brain function modulated by physical exercise by examining both human and animal studies.We will pay especial attention to the potential role of exercise in the modulation of amyloid b turnover,inflammation,synthesis and release of neurotrophins,and improvements in cerebral blood flow.Promoting changes in lifestyle in presymptomatic and predementia disease stages may have the potential for delaying one-third of dementias worldwide.Multimodal interventions that include the adoption of an active lifestyle should be recommended for older populations.

Exercise and antioxidant supplements in the elderly

Both exercise and aging increase reactive oxygen species （ROS）, which can result in damage to cells. Aging is the result of damage caused by ROS to the mitochondrial genome in post mitotic cells and numerous studies have demonstrated an increase in ROS or their byproducts with exercise. ROS can cause oxidative stress as they overwhelm the antioxidant cellular defenses. Therefore interventions aimed at limiting or inhibiting ROS production, such as supplementation with antioxidant vitamins, should be able to reduce fatigue during muscle contraction and the rate of formation of aging changes with a consequent reduction of the aging rate and disease pathogenesis. However, it has been shown that ROS are essential signaling molecules which are required to promote the health benefits of exercise and longevity. In young individuals, ROS are required for normal force production in skeletal muscle, for the development of training-induced adaptations in endurance performance, as well as for the induction of the endogenous defense systems. Thus, taking antioxidants during training, in young athletes, seems to be detrimental. However, antioxidant supplementation may be expected to be beneficial and is receiving growing attention in the active old population. In this manuscript we review the literature associated with the main areas of interest in this topic.