I have plantar fasciitis on my left heel. It started 6 weeks ago after running a series of sprints with "barefoot" shoes. I typically do sprint workout 3 times a week with better padding. Since it has not healed How long to discontinue sprinting?

Ask your doctor. especially if your not healing well. Get a second opinion from a podiatrist to see what the cause is. If calcification's present from a heel spur, then you may need to have it lasered. Probably won't go away on its own. Always get 2nd opinion. You may have more going on than you think! So see a doctor soon. Good luck!
Plantar fasciitis. Hi Tim0245 ~ I am a veteran of many marathons. I get it ! Plantar fasciitis can be very persistent and debilitating. The longer you rest the better the outcome. No "cast in stone" recipe. I would guage a/c symptoms. MILD: 2 wks, MOD: 1 month SEVERE:sometimes you need to stop for 6 mo - 1year NOTHING helps except rest. VITAL: when you re-start STRETCH, STRETCH STRETCH ! before you run.
Running shoes. Get rid of the barefoot shoes. Unless you have perfect feet, you need biomechanical control, not padding or cushioning. Get a good controlling lightweight running shoe. If that doesn't , see your local podiatrist for a good pair of orthotics. If you do this, you could run tomorrow.
Cold muscles? Do you stretch before you sprint?. If not you r running on a cold muscle. I do not care for barefoot shoes in that they do not allow to adapt to the surface real well. When you go to the beach you ever notice that your feet grasp the sand? and you do not trip. well when you leave the beach the shoe functions to adapt your foot to the surface whether it be made of pebbles,stone or sand. then you.
The reaction. to normal barefoot running indicates that an inflammatory response is initiated too easily. Oddly enough this is a reflection of brain (yes, brain) unfitness. Try 1. get rid of sugar and sweeteners and 2. try taking a vitamin B supplement.
Until . You feel better? Try wearing arch supports and forget about those "barefoot shoes"...