 A Better Life with Dr. Sanjay Gupta. What if I told you there was a tool that you could use to relieve soreness, increase flexibility, decrease inflammation, and it only costs about $5? You'd probably say, too good to be true. Well, I'm talking about a foam roller. CNN fitness contributor Lisa Santus recently wrote that a comprehensive analysis of 49 studies found that engaging in foam rolling sessions of just 90 seconds to 2 minutes did the trick.