Warm Toes in Winter: Boots, Socks and More

Author: 
Howard E. Friedman, DPM
Date: 
01/01/2012
Source: 
Trail Walker

Overboot will keep boots or shoes dry.

Hiking on a truly frigid day should make a sane person nervous. We are mammals after all, fur-less, warm-blooded, engineered to function optimally at a core body temperature of 98.6 degrees Fahrenheit (F), more than 60 degrees above the freezing point. Simply put, we are not designed for the cold. And nothing says “cold” like the gnawing pain of icy toes.

The Body’s Design Challenge

The human body is designed to preserve the temperature of the important organs in the chest and abdomen even at the expense of the extremities. In cold conditions, warm blood will be shunted to the body’s critical core organs to maintain the right temperature.

In all conditions, the amount of blood that can flow into the toes is limited by the size of their very small arteries; further, the toes have a large surface area relative to their size, resulting in significant heat loss. Indeed the surface temperature of the toes is often 10-20 F less than in other areas of the body even while indoors. Moreover tight laces and thick socks can further constrict the blood flow to the toes.

Another challenge to keeping toes warm while winter hiking is snow condition. Early morning’s hard-packed, firm, and relatively dry snow may, by afternoon, be a slushy mix that makes the feet cold and wet.

Meanwhile, a boot and sock warm enough for active winter hiking may be under-insulated to keep the feet warm during a lunch break. If the core body temperature drops, the feet will become even colder. And if perspiration is not wicked away from the feet, the dampness will accelerate the loss of heat; feet may become encrusted in an icy coating.

Before Thinking About Boots

Before deciding on footwear, the hiker must dress appropriately from head to toe to maximize insulation and preserve heat loss throughout the entire body. A cold core will lead to even colder toes. The hiker must likewise be adequately hydrated before and during the winter hike as dehydration will also lead to cold extremities. Keep in mind that caffeine, nicotine, and alcohol all are reputed to lead to constriction of blood vessels, and thus to reduced warming action by blood flow.

Before setting out, the hiker should assess the status of the terrain on the trail. Walking on hard-packed snow below the freezing point requires insulation but not specifically waterproofing. Hiking in deep snow above freezing requires less insulation but waterproofing. Hiking at a moderate to strenuous pace without stopping, even in below freezing temperature, may require less insulation since the activity of hiking will promote warmth to the toes. But, planning a full day out with rest stops will require extra layers for the lulls in activity. During the rest stops the hiker should change into dry socks if necessary. Up to a half-pint of fluid can be lost from the feet through perspiration becoming trapped, and frozen, in the socks and boots.

The Standard Solution

For a moderate to strenuous hike in fairly dry snow and temperatures close to the freezing point, most hikers will be comfortable in an insulated, waterproof, over–the-ankle boot with layers of socks. A thin wicking sock made of polypropylene or wool under a thick insulating sock made primarily of wool can be a quite effective insulating combination. Do not lace the boots too tightly, to avoid constricting circulation, and change socks when wet. If wetness is anticipated, hikers may add a waterproof sock over their insulating sock. One popular brand is Rocky Gore-Tex socks. To accommodate extra layers, winter boots may need to be one size larger than usual.

Waterproof, breathable, insulated boots abound. They are insulated with materials like Thinsulate or Primaloft, synthetic microfibers much thinner than standard polyester fibers. They are added to boots in increments of 200 grams/square meter. Manufacturers equate increased insulation with a lower temperature range of comfort. L.L. Bean, for example, advertises insulated winter boots that they have tested to be warm during active outdoor activity like quick-paced hiking or snowshoeing with 200 gm of Primaloft to be warm to minus 5 F, 400 gm of insulation tested to minus 40 F, and a 600 gm Primaloft boot that they have tested to minus 50 F.

But determining a comfort range depends on many factors, and the same boots L.L. Bean says will keep feet warm during jogging or snowshoeing to minus 5 F, they estimate will keep feet warm only to 30 F during regular walking. One specialty winter boot company, Baffin, says its boots with a thick inner boot are tested to minus 100 F!

When hiking in several inches of snow or in situations where snow or ice could be kicked up and land inside the boot or wet the lower pants leg and slowly drip into the boots, hikers should add a gaiter, a water-resistant fabric sleeve that covers the lower portion of the leg and the top portion of the boot, including the opening around the ankle. The gaiter effectively prevents snow, slush, or water from entering the shoe around the ankle area. Gaiters come in different heights and materials and methods of attaching to the top of the boot. They are secured to the bottom of the boot with a strap.

When Standard is Not Warm Enough

Ed Viesturs, America’s best known mountaineer, recently posted that he finally found comfort for his cold toes while climbing Mt. Vincent in the Antarctic in 2011 by donning a neoprene overboot, that completely encloses his plastic mountaineering boots but also includes an integrated gaiter. Though hiking in the Northeast does not pose the challenges of the Antarctic, Mr. Viesturs’ solution for warm toes is now being used from Norway to the Himalayas, from the Antarctic to the east coast of the United States. Indeed, one company, aptly named Forty Below, the temperature at which not only human skin, but mercury in thermometers freezes, specializes in creating insulating neoprene overboots that can form-fit to any type of shoe from a flexible running shoe to a stiff mountaineering boot. A few companies offer overboots. Products vary in their weight, height, ability to accommodate traction devices, and other features.

Non-Standard Approach

Avid hikers have long strived to develop a light-weight system for winter hiking and snow-shoeing. Many believe that lighter-weight footwear is more comfortable, enables one to hike further, and that unrestricted motion in a flexible shoe helps keep the feet warmer.

One such system for hiking in snowy cold temperatures incorporates a liner sock, an insulating sock, a non-waterproof non-insulated trail runner shoe, an insole, a gaiter, and a waterproof Gore-tex sock, explains Will Reitveld, senior editor for gear and apparel, in the on-line publication BackpackingLight.com. This layering system could be further modified by replacing the light trail runner with an insulated light hiking boot and a neoprene overboot for snowshoeing in colder temperatures, he writes.

Toes still cold?

A few more warming aids are available to the hiker suffering with chronically cold toes. Chemical warmers that become activated when exposed to the air can be placed under a sock and may add about five degrees of warmth for a few hours to the immediate area it contacts. During a rest break, they can be placed into a boot in advance to “pre-heat” the inside of the boot, suggests Joel Attaway, president of Forty Below.

In addition, some pre-fabricated foot beds are reportedly quite helpful in providing further insulation. Toasty Feet Insoles are a favorite of Will Reitveld, while Mr. Attaway recommends Spenco Polysorb, which he says is a good insulator due to its closed-cell flexible neoprene and shock absorbing qualities.

Overall, hikers should be actively engaged in thinking about and planning their winter cold weather footwear. Simply lacing up the insulated boots and hoping for the best is not sufficient, as it may very well lead to a curtailed hike or even extremely painful feet and toes. With a better understanding of how to apply the concept of layering to footwear, hikers should be able to customize their footwear to their planned hike and modify it as needed even during the hike.

Howard E. Friedman DPM is an avid hiker, a podiatrist in Suffern, NY, and a frequent contributor to Trail Walker of articles relating to hiking and health. Find his articles on our website at nynjtc.org/news/health-news