Introduction

Impaired cognition and mobility are common in older adults and they often coexist due to shared pathophysiology.1 Worldwide, one new case of dementia is detected every 3 s.2 Exercise improves cognitive function and reduces the risk of mobility disability and falls.3–5

Leaders in physical activity and exercise research are aiming to delineate what (e.g., type, duration, frequency and intensity) exercise should be recommended and when (e.g., midlife versus late life) it is best done for promoting cognitive and mobility outcomes in healthy individuals and in those at risk for cognitive impairment. Two other key questions are how (e.g., neurotrophic factors, cardiovascular fitness) and for whom (e.g., biological sex, gender) does exercise benefit cognition and mobility. Understanding mediators (i.e., how) could help maximise gains by enhancing intervention elements that impact key mechanisms at lower cost and/or risk. Identifying moderators (e.g., who, when)—factors that either attenuate or amplify the effects of exercise—will enable precise recommendations for individuals with similar characteristics (i.e., subgroups).

In this two-part editorial series, we focus on for whom factors that may moderate the effect of exercise on cognitive function and mobility outcomes. In Part 1, we focus on biological sex and gender. Biological sex is defined as the genetics, gonadal hormones and phenotype resulting from XX versus XY chromosomes. Gender refers to the social, environmental, cultural and behavioural factors that influence individual actions and experiences. In Part 2, …