For seasoned runners, being prepared from head to toe is key to success, so when they lose their toenails due to a common ailment known as runner's toe, it can be an impediment to their routine. According to a podiatrist at Baylor College of Medicine, there are some prevention methods that runners can take to help avoid toenail loss.

"You don't need to be a marathon runner to have this problem," said Dr. Ronald Lepow, assistant professor of orthopedic surgery at Baylor. "Regular runners very frequently experience toenail issues, and it really comes down to ill-fitting shoes."

Lepow said that it occurs in stages. Sometimes the nail or nails turn a dark color, which is caused by bleeding that's taking place under the nail that can't escape. This is usually painless, but sometimes the entire nail will fall off or the dark part of the nail will advance toward the end of the toe and grow out.

The later stage can be what is referred to as a subungual hematoma, or a blood blister. This can be uncomfortable and may require treatment, which could include removing the nail or part of the nail under a local anesthetic.

Because this issue is caused by the toe or toes slamming up against either the end or top of the shoe, Lepow said that running shoes should be about a half-size larger than regular street shoes. This prevents friction as the toes move up and down while running.

Additional measures:

  • Lace the shoes tighter – it prevents the foot from sliding around in the shoe
  • Trim toenails appropriately
  • Apply tape to the nail or nails for the run
  • Wear thicker or moisture-wicking socks to keep the feet dry
  • Purchase toe caps for the toes that are most likely to be affected
  • Don't wear nail polish on the toenail – it prolongs the injury and doesn't allow the nail to breathe

When pain develops due to the pressure of the nail pressing down, it's time to see a podiatrist, who can take the nail off under a local anesthetic. This procedure requires little to no recovery time.

Be aware that these symptoms also could be caused by other issues, Lepow said. One such possibility is a fungal infection of the nail, or onychomycosis, in which the nails are thick, brittle or discolored (yellow or dark colored). It also can be a sign of melanoma, which can be life threatening. If a dark spot on the doesn't grow out, it's important to see a podiatrist.