Can the Brain Benefits of Exercise Be Enhanced Without Additional Exercise?

Abstract

Exercise is increasingly becoming accepted as "medicine" for diseases of both brain and body 1. For the brain, exercise offers chemical, cellular and structural benefits, including enhanced generation of new neurons, glia and blood vessels 2-5 , increased expression of neurotrophins (such as brain-derived neurotrophic factor (BDNF) 6,7), dendritic remodeling 8,9 and stabilization of stress responses 10 and inflammatory signaling 11. These mechanisms of action directly counteract those present in disease states. For example, the depressed brain is characterized by decreased synaptic plasticity, hippocampal neurogenesis and BDNF 12 , all of which can be reversed by exercise. While a great deal is known about how exercise benefits the brain, there are several reasons why research is needed on how to reap those benefits with minimal exercise time. First, most people do not exercise much. Research-based guidelines for weekly physical activity for various age groups have been proffered by many public health agencies, including the World Health Organization 13. While these help to raise global awareness of the importance of exercise for the maintenance of health, most people do not meet minimum guidelines. For example, among Americans, only about 20% of adults, and 27% of adolescents meet the minimum exercise recommendation for their respective age groups 14. One of the most commonly stated barriers to physical activity is a lack of time 15 , prompting studies of high-intensity, short duration exercise regimens, which may offer benefits similar to those of much longer duration 16. High intensity exercise may work for healthy people, but another barrier to exercise is physical disability. For example, deconditioning and paresis often occur