Published July 25, 2008 11:56AM
Welcome to the dog days of late summer, when temperatures soar, clouds vanish and the sun rules like an angry god. If your plans include biking, running, hiking – and especially backpacking where you’ll be outside 24/7 – you need to be aware of the physical implications of high temperature exercise. Most outdoor folks know about heat illnesses like heat exhaustion and heat stroke, but here’s a refresher anyway:
Heat exhaustion can be a vague condition to diagnose. Basically, if you’re flushed, tired, sweating and feeling dizzy, nauseated, or weak, and can’t continue to exercise in hot weather, you’ve got heat exhaustion. Chances are you’ll feel wiped out for several hours even if you stop, cool off and hydrate – which is the preferred solution.
Pushing past heat exhaustion (all too common in race, team sport and ‘wilderness therapy’ situations) can lead to much more serious heat stroke, where your body temperature rises to levels that short-circuit the normal responses. You’ll stop sweating, and often begin hallucinating. People with heat stroke need to be actively cooled, hydrated, evacuated and hospitalized. Without immediate treatment it can be fatal. Google this stuff for more detailed info.
The good news is that military and sports physiologists have proven you can radically increase your tolerance for exercising in hot weather, just like you can acclimatize for altitude. The time required is similar.
The short version: You need to gradually increase your exercise in heat hard enough to create profuse sweating, although even sedentary exposure to hot environments will also increase your tolerance some. A mere one to five days of increased hot weather training can reduce your heart rate during hot weather exercise by 15-25%.You can seriously reduce your potential for heat exhaustion with eight days of heat training, such as intermittent run-walk sessions that gradually push your limits. For maximum effect, gradually increase the length and intensity of your hot weather exercise for at least 14 to 18 days – and do maximal intensity exercise in cool weather environments while you’re at it, because high-end aerobic capacity always helps.
Thebest set of simple guidelinesfor most users comes courtesy of the U.S. Army
The bad news is that heat acclimatization is lost quickly. It can disappear completely within 18 to 28 days. Older dogmas that women or the elderly were less adaptable have gradually disappeared as more research has been done. However, lean people are less affected by heat than obese folks, who survive better in cold, but have a tough time shedding body heat when the mercury soars.
The concept of heat acclimatization has huge implications for folks who work or live in an air conditioned environment and usually train in cooler places like health clubs, especially if they’re heading for that once-a-year big trip and aren’t in top shape to begin with. Without heat acclimatization, you’re at risk for heat stroke and heart attacks. Failure to understand heat acclimatization has led directly to numerous deaths by hikers in the Grand Canyon, and kids taking ‘hoods in the woods’ wilderness therapy programs, where acclimatized counselors too often think the new kid is just acting out.
Even if you’re not the type who’ll push hard through pain and discomfort, acclimatizing properly to heat will make your summer adventures faster, longer, safer, and a lot more comfortable. Cool huh? –Steve Howe
Rescue and Survival News:
Follow-up: Good news.Patrick Higgins, the hiker from a men’s leadership workshop lost in Hell’s Canyon near Estes Park, was spotted by Civil Air Patrol aircraft, tired and dehydrated, but otherwise unharmed. He was escorted to a nearby road by ground crews.
Another bear attack: On Wednesday, July 23rd, about 10:30p.m., a Kenai Princess Lodge worker at Cooper Landing, in the Kenai Penninsula of Alaska, was mauled by a brown bear while returning from a hike and very near the lodge parking lot. Abi Sisk (21) of Logan, Utah underwent surgery for scalp lacerations and is in critical condition, but was conscious, talking, and expected to survive. State troopers are looking for the bear, but claim that roughly 25 bruins use the immediate lodge area, which sits along the salmon-rich KenaiRiver. Alaska salmon are currently spawning, so brown bears (coastal grizzlies) are congregating near salmon streams. The Anchorage Daily News story linked above also has other links to bear news, and a great interactive sat-tracking map of bears in the Anchorage/Chugach area.