What Causes Foot And Leg Tingling?

I have this vibrating feeling in my right foot and lower leg, much like a cell phone vibrates when it is ringing. Any idea what this is? It is intermittent. I am 62, 5'7", 220. Have a history of heart disease, but nothing recently since my triple by-pass two years ago. Last visit to my heart doctor was less than i month and all was well.