Two new studies show that walking and other physical activity can delay memory loss in people at genetic risk of Alzheimer's.

One study looked at the impact of walking on 2,985 older adults, both black and white, tested for APOE status and followed for 10 years. Participants with the APOE4 genetic mutation showed a steeper decline in cognitive function. The study showed that walking had a protective effect, and this effect was strongest in those with APOE4.