Effects of Exercise on Brain and Cognition Across Age Groups and Health States

Abstract

Exercise has been shown to benefit brain structure and function, particularly in aging populations. However, the mechanisms by which exercise exerts its effects, especially in humans, are not fully understood. This review argues that one reason for this knowledge gap is that exercise likely operates through multiple levels of mechanisms. Furthermore, the mechanisms of exercise may vary depending on factors such as age and health state. We discuss the state of evidence at each of three levels of analysis (molecular/cellular, brain structure/function, and mental states and higher-order behaviors) and highlight consistencies across these levels, inconsistencies within them, and knowledge gaps. Lastly, based on these, we speculate about which mechanisms of exercise may be universal across age groups and populations versus those that might be distinct to specific age ranges or populations.

Keywords: brain; cognition; exercise; lifespan; mechanisms; physical activity.

Figure 1.

Evidence-based mechanisms (only those confirmed by RCTs) of exercise that contribute to its salutary effects on cognition. Evidence is presented across three different levels of analysis and separated by age group to highlight emerging patterns and existing gaps in evidence. While there are complexities in defining specific age ranges for developmental periods such as adolescence, age group is used to simplify the presentation of the studies discussed here. Level 1 refers to cellular and molecular signaling pathways. Level 2 refers to brain structural or functional pathways, and Level 3 refers to psychosocial pathways which are defined as higher-order behaviors or mental states.