by Sara Alam, Linda Partridge, Nazif Alic Globally, the growing proportion of older individuals is imposing personal and societal costs. However, interventions that slow aging are possible; for example, dampened nutrient signaling pathway activity in animal models promotes better health later in life. Recent findings indicate that such interventions have long-term effects even when applied transiently in early adulthood, forming a “physiological memory.” Similar memory has been extensively documented in human epidemiology, where the health of older people is shaped by their earlier environmental exposures, such as diet composition. This Essay argues that the study of the biology of aging should encompass determinants of healthspan across the entire life course.