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Too Much Heat or Not Enough

Craig Isenberg is an instructor for the Wilderness Medicine Institute of the National Outdoor Leadership School (NOLS) and the Trek Program Manager at Gray Wolf Ranch. He’s a Wilderness EMT and has extensive paddling experience in the San Juan Islands, British Columbia and Alaska.

At the 2007 West Coast Sea Kayak Symposium, Craig gave a very informative class, Extreme Climates: Identifying, Treating and Preventing Hypothermia and Heat Related Illnesses, that covered both extremes of the human temperature range. As boaters, we usually focus on hypothermia, or low body temperature. In addition to hypothermia, Craig also emphasized that without attention to maintaining our fluid levels, we can also suffer from heat exhaustion or dehydration.

But, how do we get dehydrated when we’re floating around in water? It often comes when we dress up for cold water immersion in drywear and wetsuits. It’s a hassle to strip down to urinate, or in the case of sea kayakers, it’s difficult to get to shore or pee while in the boat. We’re exercising, generating heat, perhaps overdressed and not drinking adequate fluids. Symptoms of dehydration include headaches, nausea and/or vomiting, fatigue, muscle cramps, dizziness, being thirsty and having pale/cool/clammy skin. Treatment of this condition requires cooling of the body (sponging with water to induce evaporative cooling works well), re-hydration with cool, nonalcoholic beverages, a small amount of salty food, shade and rest.

Water we drink in excess of what our body can absorb gets passed out as urine. We can absorb approximately a quart an hour, so it’s better to drink small amounts frequently, rather than gulping large quantities all at once. Also, eat food periodically to help keep the electrolytes in balance.

Hypothermia, the excessive loss of body heat, can result from a swim in cold water, but also from getting wet on a rainy, overcast day. Read Cold Water Protection and Hypothermia, an excerpt from Whitewater Rescue Manual by Charlie Walbridge and Wayne Sundmacher. The article explains the body mechanisms of hypothermia, its symptoms and prevention. Craig demonstrated a very efficient way to warm someone suffering from hypothermia via a “hypothermia wrap.” In mild to moderate hypothermia, you can assist the person in removing wet clothing. If you have someone in the severe stages, with suppressed heart and respiratory rate, cold/blue skin and muscular rigidity, it is best to cut off wet clothing. Also, be very careful in moving them, as excess movement can induce dangerous heart rhythms, which can lead to cardiac arrest.

Items used for hypothermia wrap are laid out.

A “hypothermia wrap” can be made from items usually found on any on-the-water or backcountry trip. You need a waterproof outer layer (tarp, tent fly, rain canopy), sleeping pads (River Beds, Paco Pad/Therma-A-Rest, foam type) for insulation from the ground, sleeping bags (or blankets, dry clothing, etc), head covering and water bottles.

Step 1: A paco pad, NRS River Wing and sleeping bag are laid out.

Here Virginia lays out a Paco Pad on an NRS River Wing and places a sleeping bag on top of it.

The hypothermia victim is preped for wrapping.

Our “victim,” Tyler, is placed in the second sleeping bag. We lose much of our heat from our heads, so he is wearing a wool beanie. To help warm the person, you can put warm water in water bottles and place them in areas like the neck, armpits and sides of the chest, where major blood vessels are near the surface. Be sure to wrap the water bottles in clothing articles, stuff sacks, etc so the warm bottles aren’t in direct contact with the skin.

A third sleeping bag is wrapped around the hypothermia victim.

Virginia is laying a third sleeping bag on top for additional insulation.

The hypothermia victim is finally wrapped in the river wing to complete the Hypothermia Wrap.

Virginia has folded the River Wing material tightly over Tyler in a “burrito-wrap” fashion.

In the field, using a hypothermia wrap similar to this is an excellent way to warm a person in the mild to moderate stages of hypothermia and to stabilize someone with severe hypothermia. Anytime you have someone in severe hypothermia, you must do everything safely possible to get them quickly to professional medical care, where advanced techniques can be used.

The sleeping pad insulates them from the cold ground, the sleeping bags and head covering work to hold in their body heat and the waterproof outer covering serves as a vapor, wind and moisture barrier to protect the insulating layers and help hold in the body’s heat. The outer cover can be pulled loosely over the victim’s head to keep rain or snow off.

If you’re wrapping a person in rainy/snowy/wet conditions, do your best to keep the inner side of the outer cover and the insulating layers dry. You may need to set up a shelter canopy, have others hold a tarp overhead or do the work in a tent.

Hopefully you’ll never be faced with the need to use this technique, but having the knowledge is an important safety tool.