WATCH: Doctors providing opioids without proper documentation: Study

  • Now Playing: People benefit from just 13 minutes of exercise, study finds


  • Now Playing: Genetically modified mosquitoes could eradicate malaria


  • Now Playing: Amazing advancements against cancer, but not everyone benefits


  • Now Playing: FDA calls e-cigarettes ‘an epidemic’ among minors


  • Now Playing: Behind the byline: Barbara Feder Ostrov on her Prudence Hall story


  • Now Playing: How one mom changed an organ transplant policy to save her dying daughter


  • Now Playing: 14 fall sick in salmonella outbreak possibly linked to large, cage-free eggs


  • Now Playing: Sugar-Free September: Can you give up added sugar for a whole month?


  • Now Playing: Doctors providing opioids without proper documentation: Study


  • Now Playing: Olivia Newton-John reveals that her breast cancer has returned


  • Now Playing: Why Jennifer Garner’s nutritionist starts every day with a smoothie


  • Now Playing: Do probiotics really make a difference in keeping our guts healthy?


  • Now Playing: What are probiotics?


  • Now Playing: Gina Rodriguez wants to talk about your period


  • Now Playing: A step-by-step guide on how to ‘break up’ with your phone


  • Now Playing: Globally 25 percent of adults aren’t getting the recommended amount of exercise: WHO


  • Now Playing: More cases of Salmonella linked to Honey Smacks cereal: CDC


  • Now Playing: Salmonella outbreak linked to popular cereal


  • Now Playing: New advice on kids’ concussions calls for better tracking


  • Now Playing: 61-year-old CEO shares his tips for staying fit at any age