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Footcare: Moisture, Cold and Trenchfoot

Jon Vonhof

At one time or another, every one of us has been on a hike where our feet were wet and cold for a long period of time. In a short hike it may be for a couple of hours. On a weekend hike, it may be four to eight hours, and on a week long and thru-hike it may be four to eight hours a day for continuous days. However long the period, this wet condition can have a negative effect on our feet. Blisters may go from being minor inconveniencies to major problems. Maceration can happen. In severe cases, trench foot can become a medical issue. You will be at the mercy of your hurting feet.

Exposure

Hiking in inclement weather can test and challenge your foot care skills. Foot problems can be caused by wet and cold feet as you move through streams, and rivers, cross snow and ice fields, or hike in a downpour. Hiking in boots or shoes that do not drain or not enough dry socks to change into, where your feet are constantly wet, even from sweat, can lead to foot problems. So what happens when your feet are wet and cold and how can that affect your hiking?

Effects

As your skin becomes wet it softens and is more susceptible to blisters. If a blister forms, it is more likely to rupture. The skin then separates further. Maceration happens when skin becomes soft and wet for long periods of time. This is what has happened when you take off your socks and find your feet look like prunes. The skin is tender, and can fold over on itself, separating, and creating problems. As layers of skin separate, blisters spread and the skin can split open and bleed, and the skin becomes whitish in color It is very hard to patch feet when this happened. Feet become so tender that every step is painful.

Tips to Control Moisture and Cold

Consider the following pointers when planning any hike where moisture and cold can be an issue:

• Wear socks that have moisture-wicking capabilities. Socks made of 100% cotton should be avoided. Choose synthetic fabrics like Coolmax or Olefin or a blend of materials. Smartwool socks, made from wool, are good in wet conditions. Whatever socks you wear, change them frequently and dry the old socks.
• Foot powders that absorb moisture can help keep your feet dry. Put small containers of powder into your drop bags and in your pack. Reapply powder when you change your socks. Zeasorb or Odor-Eaters both make a good moisture-absorbing powder that does not cake up into clumps. Wipe off the old powder and grit before applying new.
• Wearing shoes that do not have adequate draining capabilities will subject your feet to extended periods of moisture. Use a heated nail to make a few small holes where your upper attaches to the lower part of your shoe or boot. Make one on each side of the heel and one on each side of the forefoot.
• Consider wearing waterproof socks. SealSkinz Waterproof MVT socks from Dupont are made without irritating seams and have a vapor-permeable membrane sandwiched between an outer layer of nylon and an inner layer of Coolmax. Their weak point is their Lycra cuff that can let in water. Another option is the Seirus Neo-Sock or Stormsock made from four-way stretch neoprene with breathable macro-porous technology to prevent moisture buildup while sealing in body heat.
• When resting or sleeping, take off your wet shoes and socks to allow your feet to breathe.

Trenchfoot

Trenchfoot is a serious nonfreezing cold injury that develops when the skin of the feet is exposed to the combination of moisture and cold for extended periods. The combination, in boots or shoes that constrict the feet, for periods of 12 hours or longer, can cause skin tissue to die. It can occur in temperatures as high as 60-degrees F if the feet are constantly wet-in other words, it does not have to be in winter conditions. Another name for trenchfoot is 'immersion foot.' Many of the multi-day adventure races can subject an athlete to trenchfoot. Under the right conditions, even a one-day exposure could jeopardize your feet.

Due to the cold, wet, and constricting environment inside the shoe, vasoconstriction (blood vessels constricting) reduces circulation to preserve heat loss. With the resulting lack of oxygen and nutrients in the blood, toxins build up and skin tissue begins to die. The skin reddens and becomes numb. Swelling follows with associated itching and tingling pain. When the skin rewarms, blisters form and when they fall off, ulcers develop, then open and weep or bleed. Left untreated, amputation may be required. If your feet appear swollen and blisters develop, seek medical attention.

Tips to Control Trenchfoot

Trenchfoot is caused by factors common to hikers: dehydration, wet shoes and socks, poor nutrition, inadequate and too tight footwear, and cold. There are specific ways to reduce your chance of getting trenchfoot:

• Carefully wash and dry your feet
• Do not sleep in wet socks
• Avoid socks and shoes that are too tight
• If your feet are cold do not add socks, they cause more constriction inside your shoes-move up to a larger shoe.
• Rewarm gently, do not use a strong heat source
• Do not rub the skin, use passive skin-to-skin contact
• Elevate the feet above the level of the heart
• Start an anti-inflammatory drug program
• Consider the use of an antiperspirant with aluminum hydroxide to reduce sweating-use this on your feet for a week before anticipated exposure

Always the Exception

In all cases there are exceptions. You or your fellow hiker might be one of those individuals for whom moisture is not a problem. Your feet actually thrive in wet conditions. Some athletes go out of their way to run through streams. If this is you, then moisture may be your friend. But be forewarned, change happens. One day your feet may go from moisture loving to moisture hating. Understanding the above tips can help you be prepared.

Understanding how moisture and cold affects your feet and knowing how to deal with them can keep you from ending your hike before you had planned and help avoid problems that can cripple.

Ed note: Jon's book "Fixing Your Feet: Prevention and Treatments for Athletes" Second Edition is available.
www.footworkpub.com