The Invisible Trail Enemy: Why Trench Foot Still Ends Races in 2026

The Invisible Trail Enemy: Why Trench Foot Still Ends Races in 2026

It starts with a squelch.

At mile 30, it’s just a nuisance, a soggy sock and a bit of pruning.
By mile 70, it feels like you’re running on raw meat and razor blades.

Trench foot is a century-old condition that still quietly ends ultramarathons, thru-hikes, and multi-day efforts.

The muddy trenches of the Somme are history but the biological reality of prolonged moisture is not.

Whether you’re wading through the peat bogs of the Spine Race, crossing endless Cornish streams at the Arc of Attrition, or grinding through a rain-soaked hundred in Snowdonia, your feet are under siege. If they stay wet long enough, they will break down.

At Trailskin, we see it at almost every wet ultra.

Here’s the medical truth, the historical grit, and the modern strategy runners use to keep their skin intact when conditions turn against them.

More Than a “Wet Foot”: The Medical Reality

To medical professionals, true Trench foot is a Non-Freezing Cold Injury (NFCI).
It’s a serious neurovascular condition that goes far deeper than the surface of your skin.

It develops when feet are exposed to cold, damp conditions for prolonged periods, leading to tissue breakdown, impaired circulation, and nerve damage.

The Stages of Failure

1) Maceration - The “White-Out”
The stratum corneum (your skin’s outer shield) absorbs water and becomes saturated. Skin turns pale, wrinkled, and structurally weak, fragile enough to tear like wet tissue paper.

This is the stage most ultra-runners reach. This stage is often and commonly referred to as “Trench foot” by the general population.

2) Neurovascular Damage
Prolonged cold and moisture cause capillaries to constrict, impairing circulation and nerve function (ischemia).
This leads to the pins and needles, or total numbness..

3) The Hyperemic Phase (The Hidden Danger)
The real pain often begins after the race.
As feet rewarm (reperfusion), damaged blood vessels dilate aggressively. The resulting burning or throbbing can be severe enough to prevent walking for days.

Ultra-Runner’s Note:
If you wait until it hurts, you’re already behind.
Maceration becomes hot spots.
Hot spots become blisters.
Blisters become race-ending.

A Century of Suffering: From 1914 to the Modern Trail

The term “Trench foot” was born in the winter of 1914.

Over 20,000 British troops were treated in a single season after standing for days in water-filled trenches. Without a chance to dry their feet, many developed infections, gangrene, and in severe cases, required amputation.

Today, the setting has changed, but the conditions haven’t.

Replace the trenches of the Somme with:

  • Peat bogs in the Pennines during the Spine Race
  • Endless stream crossings at the Arc of Attrition
  • A rain-soaked 100-miler in Snowdonia

The environment is different.
The skin’s breaking point is not.

In modern endurance sports, foot issues remain one of the most common reasons for race withdrawals.

The Modern Reality: Trench Foot vs. Maceration

In strict medical terms:

Trench foot is a non-freezing cold injury (NFCI) caused by prolonged cold, wet exposure and impaired circulation.

Foot maceration is the softening and breakdown of skin caused by prolonged moisture. This can occur even in warm conditions.

Most ultra-runners experience severe maceration, not true Trench foot. 
But in cold, wet environments, maceration can progress toward trench-foot-like damage.

Different names.

Same starting point: Feet that stay wet for too long.

The Modern Myth: “Just Keep Your Feet Dry”

Every runner hears it: “Keep your feet dry.”

In real-world ultras, that’s a fantasy.
Between sweat, rain, mud, and stream crossings, your feet will get wet.

Even with waterproof socks, your feet still sweat, and that trapped moisture can create the same maceration problems over time.

The real goal isn’t perfect dryness.
It’s moisture management and skin protection.

How to Build a Defense Layer

If you can’t keep moisture out of your shoes, you must keep it out of your cells.

1) Air Them Out

At aid stations, remove shoes and socks immediately.
Even five minutes of airflow allows the skin to shed excess moisture.

It’s also the perfect time to change into dry socks and remove dirt or grit.

At 2 a.m. pulling on dry socks can feel like a miracle, and that two-minute change can save your race.

2) Active Inspection

If you feel a fold in your sock or unusual softness, stop.

Macerated skin loses friction resistance. Once it tears, bacteria have a direct route into deeper tissue.

3) Use a Hydrophobic Barrier

Historically, soldiers used whale oil.
Modern endurance athletes use purpose-built barrier creams designed for wet, high-friction conditions.

Products like Trailskin Trench Foot Cream, and other products in the Trench Foot Cream sub-category within the barrier cream category, are designed for the “non-dry” reality of ultra-endurance events and long efforts where dry feet simply aren’t possible.

Instead of forming a fully occlusive seal, hydrophobic barrier creams aim to:

  • Repel external moisture before it saturates the skin
  • Reduce friction on fragile, wet tissue
  • Support healthier skin in damp, high-friction environments

Used before and during long efforts, they become a simple but critical part of a runner’s foot-care routine.

Simple Race-Day Foot Protocol

A basic routine used by many experienced ultra-runners:

  • Apply barrier cream before the start
  • Change socks when heavily saturated and reapply barrier cream, every 4–8 hours or at major aid station
  • Air feet for 2–5 minutes when possible (during sock changes)
  • Inspect hot spots early- don’t wait for pain

Small interventions early can prevent race-ending damage later.

The Takeaway: Respect the Conditions

Trench foot isn’t a historical footnote.
It’s a real risk any time you spend hours in cold, wet conditions.

It ended military campaigns in 1914.
It still ends race dreams today.

Your finish line depends on your foundation.
Use smart hygiene, regular checks, and a barrier that works.

Your feet can stay strong, even when the trail is soaked.

Don’t wait for the squelch.

Most runners only think about their feet after the damage starts. Don’t.

Protect them before mile one  with Trailskin.

As used by runners in the Spine Race, the ARC, UTS, Tor330, UTMB, MDS, BTU, Dragons Back and multi-day expeditions.

FAQ: Quick Hits for the Trail

Can you get Trench foot in the heat?
Yes. Known as Warm Water Immersion Foot (WWIF) or “Paddy Foot,” this occurs in temperatures between 15°C and 32°C. The maceration and pain can be very similar to the cold-weather version.

Should I pop maceration blisters?
No. Macerated skin is highly prone to infection. Keep the skin intact and apply a protective barrier.

How long does it take to heal?
Mild maceration may recover within hours once dry. True neurovascular damage can take weeks. Prevention is the only reliable solution.

What about Vaseline?
Petroleum jelly is fully occlusive. In prolonged wet conditions, this may trap sweat against the skin and potentially increase maceration risk.
It can also attract grit or sand, increasing friction inside the shoe.

 

 

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