Only on the "CBS This Morning" podcast, psychologist Kelly McGonigal joins co-host Gayle King to discuss her new book, "The Joy of Movement: How Exercise Helps Us Find Happiness, Hope, Connection, and Courage." McGonigal explains how walking just one minute a day can have a positive impact on your mental health. Plus, she shares how 1980s aerobics tapes inspired her love for movement, how exercise helped her overcome shyness and the Carly Rae Jepsen song that always gets her moving.