Temperature Swings on the Trail

At high altitude, where the air is thinner and doesn’t hold as much moisture and molecules to moderate the temperature, the thermal swings can be extreme. On the trail to Everest base camp, the higher we climbed, the greater the were the daily temperature changes. It’s wasn’t uncommon to wake up to a freezing temperature, greet the sunrise, and have its warmth take us into the mid-60s Fahrenheit by early afternoon. In the afternoon, as the sun began to go down, and whenever the clouds or mist rolled in, the reverse occured. Since we never burned camp fires for ecological reasons, once the sun went down, our activities were a few conversations, a cup of hot tea, and off to bed.

The practical aspect of this is to learn how to layer clothing. When you are encountering as much as a 50-degree temperature variation, you are wise to carry sufficient items of clothing to dress and undress on the trail. Most of us used synthetic undergarments, because cotton soaks through and doesn’t evaporate moisture well. This was followed by a long-sleeved garment, then perhaps a down vest. The outer layers was be a windproof shell, rain jacket, or down-filled jacket. We all carried gloves, a rain hood, backpack cover, waterproof pants, and a wool or synthetic hat. With all that, we had room to spare. If you are a creative packer, you can carry what you need in a daypack.

Tags: high altitude, hiking, trekking, Nepal, wilderness medicine, outdoor medicine, healthline

photo by Brian Auerbach

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ThinkFirst Foundation

Head and neck injuries are all too common, particularly in outdoor activities. As part of my activities with the Wilderness Medical Society, I have become familiar with the ThinkFirst Foundation of Canada. So far, I have been very impressed. Its mission is to prevent brain and spinal cord injuries through education aimed at healthy behaviors in children, recognizing that prevention is absolutely critical. Once a brain or spinal cord injury has occurred, it is too late, and the results can be devastating. It is wise to take the position that prevention is the only cure!

The methods used by the ThinkFirst Foundation are to promote safe behavior through educational materials, public service announcements, and reinforcement materials; encourage progressive public policy regarding injury prevention; conduct research on the causes of injury and on the effectiveness of its injury prevention programs; and develop new initiatives and programs to reach the community with the Think First prevention message.

The latest edition of Brain Waves, the organization’s newsletter, is a good example. There is an article on backpack safety, a Q&A about bike helmets, an announcement about “Smart Soccer,” a booklet that will be launched this summer to educate soccer players about the risks of soccer injuries and how to play soccer safely, and a moving story about an individual who suffered a brain injury after falling off a bicycle.

I will write more in the future about injury prevention. Until we eliminate avoidable mishaps that result in brain and spinal cord injuries, we can never cease to explore new approaches about to how to stay out of harm’s way.

Tags: ThinkFirst Foundation, head injury, spinal cord injury, injury prevention, wilderness medicine, healthline

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Hiking on Rocky Trails

Our trail to Everest base camp was challenging, with lots of uphills and downhills, big steps onto boulders and into narrow dirt cracks, and uneven terrain as the rule. Given that falls, ankle sprains, and blisters comprised our biggest risks, an ounce of prevention was worth a ton of cure. We encouraged everyone to carry at least one walking stick or pole for improved balance. Adding a third (or fourth) point of contact makes a huge difference in terms of decreasing falls, and also cushions much of the impact that would otherwise be transmitted to ankles, knees, hips, and the lower back. Whether or not your pole has a spring action built into it is not nearly as important as having the pole. If you are concerned about maintaining the environment, put a rubber cushion tip on the pole so that you don’t tear up the ground. You may not appreciate the benefit of the impact reduction from your hiking pole when you are climbing, but you will certainly notice the improvement on the way down. Be good to your knees!

Except for your pole(s), try to keep your hands free, so you can use your arms for balance like a tightrope walker, should you begin to fall. If you’re carrying your expensive digital camera in your hand and you fall to that side, guess what’s going to get smashed?

Tags: hiking, hiking pole, pole, Mt. Everest, Nepal, wilderness medicine, healthline

photo by Brian Auerbach

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Beat the Heat

The summer has begun, and with it comes the seasonal onset of heat waves. We've been suffering through high environmental temperatures recently, and with global warming, it's likely that very hot summers will be the rule rather than the exception. Humidity makes the situation worse, as it impedes evaporation of sweat, which is a major body cooling mechanism for humans. The National Weather Service has a heat index that roughly correlates air temperature and relative humidity to derive an "apparent temperature." At all temperatures, humidity makes the situation worse. For instance, at an air temperature of 85 degrees Fahrenheit, if the relative humidity is 80%, the apparent temperature is 97 degrees F. So, you must be extremely careful not to overdo it when the thermometer is rising. The most effective ways to avoid heat-related illnesses are to: (1) Stay well hydrated. Adequate water ingested during exercise is not harmful, does not cause cramps, and is your best protection. If you are sweating a great deal, you should consider replacing electrolytes by drinking an electrolyte-and sugar-enriched beverage such as Gatorade. (2) Be very watchful of the very young and very old, as they do not regulate body temperature well. (3) Stay in shape. (4) Don't drink alcohol or use recreational drugs. (5) Condition yourself for the environment. (6) Wear clothing that is appropriate for the environment, so that you can shed layers as necessary. (7) If you are sweating, towel yourself off frequently. (8) Stay out of the sun on a hot day. (9) Avoid taking medications that inhibit the sweating process. (10) Finally, use common sense - if you are in the heat and feeling poorly, seek shade or another cooler location as soon as possible.

Tags: heat, heat illness, hydration, dehydration, heat wave, wilderness medicine, healthline

photo by Paul Auerbach

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Climb High, Sleep Low

Our trek to Everest base camp began at Lukla, situated in the Khumbu Valley of Nepal at slightly more than 9,000 feet altitude above sea level. This is the usual jumping off point for a hike from the Nepal side into the Everest region, unless you come from the Tibet side or originate your journey in Kathmandu. Understanding that it's not uncommon to see manifestations of acute mountain sickness (headaches, fatigue, nausea, poor sleeping) or high altitude pulmonary edema, which is a form of fluid in the lungs (shortness of breath, decreased exercise tolerance, cough, low grade fever) at altitudes as low as 8000 feet above sea level, we were very aware of how fast we ascended, and our sleeping altitude. Many people show their susceptibility to high altitude illness in their sleeping patterns, with disturbed sleep being a manifestation of a poor breathing response to low concentration of oxygen in the thinner air at high altitude. So, we were careful to sleep at the lowest altitude that was practical for our journey, and to never ascend more than 1000 feet a day. If anyone felt poorly in a way that might represent high altitude illness, we slowed the pace of hiking and ascent, and considered the need to stay at that altitude for an extra day, or even descend if the symptoms were severe or appeared to be worsening. Fortunately, everyone was in good shape, and our group only suffered a few headaches and one episode of moderate mountain sickness.

Tags: high altitude, Nepal, acute mountain sickness, mountain sickness, Mt. Everest, wilderness medicine, healthline

photo courtesy of Brian Auerbach

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Volcanic Eruption

I was going to write more today about high altitude, but with the current eruption of Mount Merapi in Indonesia and resultant tragic deaths, I have been asked a lot of questions about the dangers associated with volcanic eruptions, and in particular, "what is a pyroclastic flow?" Since recorded time, pyroclastic flows (which I will describe below) have killed the most people, while flying solid objects (called "tephra" by vulcanologists) thrown out by the volcano are the most common killers. Usually, when an explosive volcano erupts, a cloud of gas, ash, and lava fragments rises up into the atmosphere. If the eruption cloud becomes more dense than the surrounding air, it may fall back towards the ground, propelled by the forces of gravity. This can lead to formation of an incredibly hot (more than 1500 degrees F), high-speed (faster than 180 miles per hour) avalanche of ash, volcanic gases, lava fragments and heated air, which is called a pyroclastic flow. The extreme temperatures may also generate gale-force winds. Because of the forces and temperatures involved, no living being caught in this infernal river can survive. Most human victims die from suffocation, exposure to the heat, or burial under the volcanic debris. Anyone who travels in the vicinity of an active volcano should be aware of the risks and have a well thought out, realistic evacuation plan.

Tags: volcano, volcanic eruption, pyroclastic flow, lava, wilderness medicine, outdoor medicine, healthline

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Back from Mt. Everest Base Camp

Welcome to the first post of the Outdoor Health (Wilderness Medicine) Blog on Healthline. I’m very much looking forward to sharing information and thoughts with readers, and even more so to learning from everyone as comments and useful ideas and concepts are posted. Outdoor activities are the fastest growing segment of recreational activities, so when you add that to science, exploration, industry, rural living, and adventure travel, there is a tremendous amount to discuss and a lot of useful learning.

I recently returned from a trek to base camp at Mount Everest, where I visited Dr. Luanne Freer, a wonderful friend and superb emergency physician from Bozeman, Montana who is the current President of the Wilderness Medical Society. She runs the medical clinic at the base camp, where she provides support to climbers and others who venture that far into the Himalaya wilderness. Another good friend, Eric Johnson, M.D., who is President-elect of the WMS, was there with her for this climbing season. My son, Brian, accompanied our group, which made the trip all the more special.


In future posts, I will be talking about some of the medical situations we encountered. The purpose of our trip was to teach a continuing medical education (CME) course on wilderness medicine to a group of health care providers, and use the proceeds to fund a future medical student research project. We encountered spectacular scenery, wonderful people, and plenty of medical situations along the way. Thank goodness the political situation in Nepal took a dramatic turn for the better, which allowed us to make this journey.

Let's have this blog be informative, useful, and fun. Let me hear your thoughts and opinions. Join with me as we embark on a trek through medical information that will help you be safe and healthy in the great outdoors!

Tags: high altitude, Nepal, Mt. Everest, wilderness medicine, healthline

photo by Paul Auerbach

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