Preventing Blisters and Chafing on a Marathon Day

Blister Bandaged Feet
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Walkers and runners who never get blisters on a 10K may discover that they aren't immune to them at longer distances. This is why it is essential to get your longer distance training walks in — to see what areas of your feet get blisters and when they start forming. Those long training walks also toughen your feet gradually so you should get fewer blisters.

As you increase speed and sweat, you may also discover that you chafe — armpits, bra line, crotch, and nipples are especially prone to this painful problem.

Anti-Blister Strategies for the Marathon and Half Marathon

Your feet are unique. What works for your training buddy may not work for you. Try these different tactics for preventing blisters.

  • The right shoes: Get shoes that are big enough so your toes have enough room as your feet swell during the walk. You may also lose toenails if your shoes are too tight or not long enough. But you need a good fit so your foot isn't moving around too much in the shoe once it has swollen to its maximum. A sloppy fit can also produce blisters. 
  • Proper socks: Cotton socks hold perspiration next to the skin, softening it and making it more prone to blister. Get CoolMax or other synthetic socks, or double-layer socks. Experiment with your socks on your longer distance practice walks. 
  • Lubricate your feet: Apply lubricants designed to prevent blisters and chafing such as BodyGlide, Run Goo, or Sportslick. Petroleum jelly is another common lubricant, although it really gums up your socks. Apply the lubricant liberally before putting on your socks. Don't miss the areas between your toes. You may also want to stop at 10 miles and apply more lubricant. 
  • Dry out your feet: The military first developed the tactic of applying a strong antiperspirant to the feet daily, to dry them out. Be sure to test this idea well in advance of your marathon to see if you tolerate it well. Add cornstarch to your socks to further draw away moisture.
  • Tape up your feet: If you know from experience that you always blister in a certain area, tape it up with sports tape, moleskin, or gel blister bandages. Some walkers use plain old duct tape, although that can irritate.

Preventing Chafing 

Chafing happens where sweat produces salt crystals and skin rubs on skin. You'll experience it most often at your armpits, crotch, thighs, nipples all around your bra and bra straps or heart rate monitor chest strap. If you wear a hydration pack, you may also find chafing where it rubs on your back and shoulders.

You can wear spandex shorts or tights to help prevent upper thigh chafing, but chafing in most areas is best prevented by lubrication. Use BodyGlide, Mission 5-Hour Anti-Chafe Cream, SportShield silicone roll-on, Squeaky Cheeks Performance Powder or similar preparations that won't stain your clothing and will wash out (unlike petroleum jelly). Apply liberally to all areas prone to chafing before the race, and carry some along to apply during the event.

First Aid During the Marathon or Half Marathon

Carry along blister block bandages, moleskin, sports tape or other first aid products to treat any area that begins to feel hot. Stop immediately and apply them to prevent a fully developed blister, or to keep it small. Once you have a blister, your gait will be different due to the pain. You'll find more aches and pains the next day due to your gait being disrupted.