Memory problems can begin in people as young as age 20 and mental decline can occur by the time we reach age 40. 2 Weeks to a Younger Brain book explores the latest research in brain science that shows that improving memory also strengthens physical health by reducing the risk of diabetes, heart disease and stroke. There are many easy changes that can be made in one's daily lifestyle that can improve brain health. It takes only two weeks to form new habits that bolster cognitive abilities and help stave off, or even reverse, brain aging.