This true account of the Canadian athlete Olga Kotelko is taken from Pang’s book “Rest.” Olga won hundreds of senior track and field events before her death at 94. Her regimen had a dramatic effect on her brain’s structure. Compared to other people her age, Kotelko’s brain had greater white matter integrity (this correlates with increased capacity for reasoning, self-control, and planning). Along with her levels of fractional anisotropy (a measure of brain connectivity), and her healthier brain helped he perform better on cognition and memory tests. She grew up on a farm and spent a career as a teacher. What makes her so remarkable is that she didn’t start competing until late in life: she started training at 77.