How to Prevent Blisters on Long Trail Runs

Quick answer: Blisters come from friction on skin that is warm and damp. To prevent them on long trail runs, wear shoes that fit, choose moisture-wicking socks instead of cotton, keep your feet as dry as you can, and protect hot spots early with moleskin, a soft bandage, powder or petroleum jelly. Stop and fix a hot spot as soon as you feel it rather than running through it.

Why trail runners get blisters

Blisters form where skin rubs, and moisture makes it worse. That is why the American Academy of Dermatology (AAD) focuses its advice on shoe fit, moisture-wicking socks and reducing friction.

1. Get the fit right

The AAD advises wearing shoes that fit properly and are neither too tight nor too loose. Test new shoes on short runs before a long one.

2. Choose the right socks

The AAD recommends nylon or moisture-wicking socks and suggests two pairs of socks for extra protection. Avoid cotton, which soaks up sweat and moisture. Carry a spare pair on long runs or routes with water crossings.

3. Protect known hot spots before you start

• Cover areas that blister often with adhesive moleskin or another soft bandage.
• Apply powder or petroleum jelly to reduce friction, as the AAD suggests.

4. Treat hot spots on the run

The AAD advises stopping if you feel pain or discomfort or your skin turns red. Take the shoe off, dry the area, and cover it. Pack a small foot kit in your vest: moleskin or tape, a few bandages and a spare pair of socks.

5. If a blister forms

The AAD advises loosely covering the blister with a bandage and avoiding popping it, because that can lead to infection. Keep it clean and covered. See a dermatologist if you notice redness, pus, or increasing pain or swelling.

Carry a small foot kit

A spare pair of socks and a few bandages weigh very little and fit in a vest pocket. They fit in a front pocket of a 5L vest like the ROOT5. For a full list of what to carry by distance, see the trail running gear checklist.

FAQ

Should I pop a blister during a race?

The AAD advises against popping or draining a blister because it could lead to infection, and says only a large, very painful blister may be drained with a sterilized needle.

Source: American Academy of Dermatology, how to prevent and treat blisters. This guide is general information, not medical advice.