This list of common outdoor health problems includes preventative measures and remedies recommended by the NOLS Wilderness Medicine Institute. Our goal: help you stay healthy when you’re out enjoying nature.

Sunburn

Sunscreen

Sunburn, caused when your skin gets exposed to too much of the sun's ultraviolet light, is a common, but easily avoided, problem in the outdoors.

Prevention: All outdoor adventurers, but especially those who are fair-skinned, should wear sunscreen with an SPF (sun protection factor) of 30 or higher. The American Academy of Dermatology and the Skin Cancer Foundation recommend an application of sunscreen every 2 hours, even on cloudy days. They also offer these tips:

  • Minimize your exposure to the sun between 10am and 4pm. Potential for skin damage is greatest around noon (or 1pm during daylight saving time). At these peak-intensity hours, a fair-skinned person could suffer skin damage in less than 15 minutes.
  • Always shade your head, neck, ears and eyes, particularly at high elevations, where a thinner atmosphere allows more UV rays to reach your skin. Sand and snow can intensify the sun's impact. Some outdoor clothing comes with SPF ratings. Fabrics with tighter weaves help keep the sun off your skin.
  • Sunscreen should block both UVA and UVB rays (this is sometimes called “broad-spectrum sunscreen”). Examine product spec sheets or packaging to verify this level of protection.
  • Your sunglasses, too, should offer both UVA and UVB protection.
  • Check with your doctor to determine if any medications you are taking increase your susceptibility to sunburn.

Remedy: If you do get burned, soothe damaged areas with an aloe-based skin cream. Keep these areas covered for the remainder of your trip (either with clothing or a strong sunscreen) to avoid further damage. If the sunburn is serious and you experience persistent nausea, chills or fever, seek professional medical attention.

For more information, see the REI Expert Advice article, Sunscreen: How to Choose.

Shop REI’s selection of sunscreen.

Blisters

Blister

One blister, the product of friction that rubs skin back and forth in a concentrated area, can mar an otherwise wonderful hiking trip.

Prevention: Blisters are easier to avoid than they are to fix. Make sure you start every trip with footwear that is broken in and fits you well. Wear clean, properly sized socks. Also, consider wearing 2 pairs of socks—a lightweight wicking liner and a thicker cushioning sock—to lessen the chance of abrasion.

Tip: On the trail, address foot discomfort as soon as it develops. A quick response can often stop a blister before it becomes serious. At the first sign of irritation, put a small patch of protective material—moleskin, 2nd Skin or even duct tape—over the affected area to minimize abrasion.

Remedy: If you know you are prone to blisters, consider applying moleskin to your typical "blister zone" before you hit the trail.

  • If a blister develops and walking becomes too painful, you could drain the blister by lancing it along its base with a clean razor blade or knife. Once this is done, soothe the area with some antibacterial ointment, then cover it with a patch of 2nd Skin (or similar product) plus a small adhesive bandage to keep the blistered area clean.
  • If the area is still sensitive, cut a doughnut-shaped cushioning patch out of Molefoam or duct tape and encircle the injured area. You may need to bulk up your circular pad with a number of layers to hold your sock and boot out away from the damaged area. This cushion will protect the area from further damage.

Shop REI’s selection of blister treatments.

General Aches and Pains

Sore muscles, headaches and joint pain are a common occurrence on more strenuous outings.

Prevention: The primary purpose of stretching before an aerobic activity is to increase body temperature. This increases blood flow so muscles can endure more force.

  • Dynamic stretching, such as a modest walk or jog, is generally preferred over static stretching for most people, though either can be useful if done carefully. For a hiker, the best warm-up is spending your first 10 or 15 minutes on the trail walking at a moderate pace.
  • If you feel the need to do some sort of pre-hike activity, you could try, for example, the straight-leg march. Begin by kicking one leg straight in front of you, with toes flexed skyward. Reach toward your airborne toes with your opposing arm. Drop that leg and perform the same motion with your opposite limbs. Aim for a half dozen or more repetitions.
  • There are many possible dynamic and static stretches. See the REI Expert Advice article, Running Basics, for other options.

Tip: Avoid the temptation to exceed your physical limits, especially early in your activity’s season.

Remedy: Most muscle aches can be fixed with a little rest and gentle massage. For headaches, take a couple of pain reliever tablets—aspirin, ibuprofen or acetaminophen—and a short rest. Joint pain is typically caused by overuse, though it can be the result of twists or unusual compressions. Again, rest is usually the best remedy. Elevating the sore joint might help alleviate pain. Taking glucosamine, a cartilage-repairing nutritional supplement, can also help joint pain and expand your range of motion.

Shop REI’s selection of pain relief.

Poison Ivy, Poison Oak and Sumac

Poison Ivy, Poison Oak and Sumac Plant

In most areas of the country, it is possible to run into one or more of these troublesome plants.

Prevention: Learn how to recognize any dangerous plants that are common in the area you'll be exploring. Poison oak and ivy leaves grow in clusters of 3, so remember the old adage: If you see "leaves of 3, let it be." Be wary of touching anything foreign to you. Keep in mind that the oily, rash-causing resin found in poison oak and ivy—urushiol—remains present in the plants even during dormant winter months. Contact with a leafless stem in January can still spawn an itchy rash. Pre-exposure lotion can be helpful. If traveling in unfamiliar territory, consider carrying a lightweight, compact field guide to help you recognize plants.

Remedy: Carry a small supply of hydrocortisone cream or another soothing, anti-inflammatory lotion to lessen the discomfort caused by skin irritations. Fluid from a rash-induced blister will not spread the rash. However, if the resin is not cleaned from clothing, boots, skin or tools, you can re-expose yourself or another person. It's the resin, not the rash, that spreads infection. A good first-aid manual will provide other useful tips on limiting the spread of rashes.

Shop REI’s selection of skin treatment.

Biting Insects

Bug repellent

Mosquitoes, flies and other biting insects are an unavoidable part of nature. Fortunately, these bug bites are usually more of a nuisance than a health hazard.

Prevention: Know your enemy and be prepared. This means identifying and avoiding the worst locations and times of year for bugs. It also means packing the right kinds of clothing (light-colored long-sleeve shirts, long pants, bug shirts, bug-net hats and so on) and using some form of topical repellent if necessary.

DEET-based insect repellents are the most effective against mosquitoes, though natural alternatives are available for those who prefer to avoid synthetic chemicals. DEET is not recommended for pregnant women or small children, especially those less than 1 year old. DEET will not hurt cotton, wool or nylon, but it can damage plastics and synthetic fabrics.

Clothing treated with permethrin, an EPA-registered chemical insecticide in use for decades, offers another effective line of defense. You can self-apply permethrin to your clothes or wear pre-infused garments from ExOfficio and others.

Remedy: First-aid products such as After Bite help relieve the swelling and itching caused by bug bites.

Tip: Some people are allergic to certain insect stings. If you are, protect yourself by avoiding risky situations as much as possible and by carrying whatever medicines you need to counteract the reactions. Make sure everyone in your group knows about your allergy and what to do if you get stung or bit.

Shop REI’s selection of insect repellent.

Stinging Insects

Bees, wasps, hornets and yellowjackets are additional winged threats you may encounter.

Prevention: If you come upon a beehive or wasps' nest, leave the area quickly and quietly. In campgrounds, avoid brightly colored clothing, shiny jewelry or belt buckles, and scented cosmetics. If you or someone in your group is allergic to bee or wasp stings, make sure to visit a health care professional for preventative injections.

Remedy: For a normal reaction to a sting (itching, redness and slight swelling) the following first-aid items may be useful: ice, baking soda, oral antihistamines (such as Benadryl, Chlortrimeton and Dimetane), epinephrine inhaler (such as Primatene), topical steroids (such as Cortaid or Lanacort) and local anesthetics (such as Benzocaine, Lanacane or Solarcaine).

Shop REI’s selection of sting/bite treatments.

Ticks

Closeup of a Tick

Ticks are nasty little arachnid bugs that can make you sick. While not all tick bites transmit Lyme disease or tick fever, it pays to be aware of these threats. Check with rangers about potential danger before you explore an area unfamiliar to you.

Prevention: Avoid areas where ticks are prevalent such as vegetated areas (woods and grasslands) where small mammals live. Tuck in your clothing—shirts into pants, pants into socks. Do twice-daily checks of your skin and hair for ticks. DEET-based insect repellents on your skin and permethrin-based insect repellents applied to clothing can repel or kill some ticks.

Remedy: If a tick is discovered, try to remove it as soon as possible. Using tweezers, gently grasp the tick by the head and lift it straight up and out. Wash the bite site thoroughly with soap and water, rubbing alcohol or iodine. Avoid Vaseline smothering, gasoline dousing, matchhead burning and other discredited folk remedies.

Note: Ticks can only pass on their diseases if they are burrowed in your skin. Touching a tick or having one merely crawl on your skin is not dangerous.

Shop REI’s selection of sting/bite treatments.

Snakebites

Partially Hidden Snake

While many snakes are harmless, a few (rattlesnake, coral snake, water moccasin and copperhead) have potentially lethal bites. Per the University of Maryland Medical Center, up to 8,000 people receive venomous snake bites each year in the U.S. (about a dozen or less typically prove fatal).

Prevention: Avoid areas prone to snakes by checking your guidebook or asking a local ranger or guide for advice. Stay on trails or in well-groomed, open areas. Watch where you're going and listen. Be cautious and alert when climbing rocks. If you see a snake, don't antagonize it.

Remedy: Never attempt to identify, capture or kill a snake, as this can easily result in a second bite victim. Follow these steps:

  • Calm yourself and the victim. Envenomation is not a given in a snakebite.
  • Immobilize the limb. Avoid compression or constriction of the extremity.
  • Transport victim to a physician or hospital for antivenom and supportive care.
  • Document the site and size of the envenomation to describe its progression to the physician.

Avoid unproven or discredited treatments that may harm the patient, such as tourniquets, ice, electricity, meat tenderizer, incision and suction.

For more information, see this REI Blog post entry, Humans vs. Rattlesnakes.

Hantavirus

Hantavirus is spread by the droppings, urine and saliva of contaminated rodents, particularly the deer mouse, cotton rat, rice rat and white-footed mouse. Inhaling fumes or dust that carries traces of rodent excreta is the most likely way humans are exposed to the virus. This usually happens during activities such as cleaning a barn or cabin, but campers are potentially at some risk, too.

As pointed out by Dr. Paul Auerbach, author of the respected book Medicine for the Outdoors, a person infected by the virus has an incubation period of 1 to 5 weeks following exposure. Symptoms include fever, muscle aches, headache, cough, dizziness, abdominal pain, nausea and vomiting, and diarrhea for a few days. This is followed by difficulty breathing, mottled skin on the limbs, shock and, sometimes, bleeding. Up to 75% of victims, he reports, may die.

Prevention: Avoid any areas with excessive rodent activity: barns, old cabins or dusty, enclosed trail shelters. Dr. Auerbach recommends the following precautions:

  • Keep food and water covered and stored in rodent-proof containers.
  • Dispose of food clutter; spray any dead rodents, nests and droppings with disinfectant prior to handling (and wear gloves when you do).
  • Clean and disinfect cabins and other shelters thoroughly before using.
  • Don't make camp near rodent sites.
  • Don't sleep directly on bare ground.
  • Dispose, burn or bury garbage promptly.
  • Use only bottled or disinfected water for campsite purposes.

Remedy: If you suspect that you or someone in your party has been infected with hantavirus, seek professional health care immediately. Dr. Auerbach points out that there is not yet any specific therapy beyond supportive care, although the antiviral agent ribavirin may prove useful.

Altitude Sickness

Altitude sickness (or “acute mountain sickness”) can affect wilderness explorers when traveling at high elevations (often above 8,000 feet or 2,400 meters). It is caused by the combination of reduced air pressure and lower oxygen levels. How fast you climb to a high altitude and how hard you push yourself can increase the odds of an occurrence.

Symptoms include a sluggish sensation often accompanied by a headache, dizziness, nausea, loss of appetite, elevated heart rate and shortness of breath with exertion. In most cases, symptoms are mild, but acute cases can be debilitating, even fatal.

Prevention: Avoid abruptly changing elevations from day to day. If you're spending your pre-hike day in a low-lying valley, you could be asking for trouble if you take aim at a 10,000-foot pass the next day. It is better to acclimatize, meaning you gain elevation gradually, or camp at a high elevation for a day or more before undertaking your hike. A general rule: Stop for a day or 2 of rest for every 2,000 feet gained above 8,000 feet high. If you do plan to climb fast, ask your doctor about acetazolamide (Diamox), a drug that can help your body acclimatize more quickly.

Remedy: Descend. If you sense the symptoms are overtaking you, seek out lower elevation quickly before your condition deteriorates and you are unable to walk unassisted. Aspirin can be beneficial for any head pain you experience. Call for emergency help if the victim has severe breathing problems, an altered state of alertness or is coughing up blood.

For more information, see this REI Blog post entry, A Good Head for Heights.