It’s unpleasant, but it’s true — as we get older, our brains get a little... hazy. As aging and degenerative diseases like Alzheimer’s kill off brain cells, the noggin actually shrinks, losing many important brain functions in the process. While exercise and a healthy diet can’t “cure” Alzheimer’s, they can help shore up the brain against cognitive decline that begins after age 45 [5]. Working out, especially between age 25 and 45, boosts the chemicals in the brain that support and prevent degeneration of the hippocampus, an important part of the brain for memory and learning.