I'm a runner and lately several of my toenails have turned black and won't fall off. is this okay? should i visit a doctor?

Nail trauma.: Sounds like your nails are being traumatized by your shoes and bleeding in the tissue under the nail. Shoes may be too tight, too loose or have a ridge on the inside that is catching your nail.

Nails : The dark color to nails in a runner is usually due to the trauma the nails take and you get a subungual hematoma or blood under the nail. It will either grow out or fall off on its own. If painful see dr.

Blood: Dark color is bruise. Complete regrowth of a toenail takes about a year. It will be shed off as the nail grows. A nail is not a living tissue: it cannot repair itself, only be replaced by new nail.