What Is Chafing (and How to Prevent It)?

Chafing is painful skin irritation caused by repetitive rubbing — skin against skin, clothing, or gear — made worse by moisture (sweat), heat, salt, and friction over long efforts. Common spots for runners are the inner thighs, underarms, nipples, and where packs and waistbands sit. It's prevented with lubricants, anti-chafe balms, snug moisture-wicking clothing, and good gear fit.

Trail RunningConceptsBeginner
Chafing is painful skin irritation caused by repetitive rubbing — skin against skin, clothing, or gear — made worse by moisture (sweat), heat, salt, and friction over long efforts. Common spots for runners are the inner thighs, underarms, nipples, and where packs and waistbands sit. It's prevented with lubricants, anti-chafe balms, snug moisture-wicking clothing, and good gear fit.
What it isSkin irritation from repetitive rubbing
Worsened bySweat, heat, salt, friction
Common spotsInner thighs, underarms, nipples, pack lines
Prevent withLube/balm, snug wicking clothing, good fit

Chafing is painful skin irritation caused by repetitive rubbing — skin against skin, clothing, or gear — made worse by moisture (sweat), heat, salt, and friction over long efforts. Common spots for runners are the inner thighs, underarms, nipples, and where packs and waistbands sit. It’s prevented with lubricants, anti-chafe balms, snug moisture-wicking clothing, and good gear fit.

Prevention

Like the running cousin of the blister; reduce it with wicking clothing and a well-fitted hydration vest.

Frequently asked questions

What causes chafing?

Chafing is caused by repeated friction — skin rubbing against skin, clothing seams, or gear — over time, especially when sweat, salt, heat, and moisture are present to increase irritation. On long runs the cumulative rubbing in areas like the inner thighs, underarms, and under pack straps wears away the skin and causes raw, stinging chafe.

How do you prevent chafing while running?

Apply an anti-chafe balm or lubricant to friction-prone areas before running, wear snug, seamless, moisture-wicking clothing (avoid cotton and loose seams), ensure packs and waistbands fit well without rubbing, and keep skin as dry as possible. For long efforts, reapply lubricant and address hot spots before they become raw.

How do you treat chafing?

Clean the affected area gently, let it dry, and apply a soothing healing ointment or barrier cream; keep it clean and protected while it heals and avoid re-irritating it. For severe or open chafe, watch for signs of infection. Preventing recurrence with lubricant and better-fitting clothing is the long-term fix.

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