The 400-meter timed walk can provide insights into an older person’s cardiorespiratory fitness; the resulting data from these walks are useful in predicting total mortality, cardiovascular disease, mobility limitation, and disability. But do leisure time activities and weight/body composition changes affect walk time? Dr Kelley K. Pettee Gabriel from the division of epidemiology, human genetics, and environmental sciences at the University of Texas Health Science Center, Austin, and colleagues believe a better understanding of this relationship will help clarify the best use of the 400-meter walk in middle-aged women.