Doug Feldewert was two hours into a marathon mountain bike race on Lost Valley Trail in Weldon Spring when he noticed that his vision was getting blurry and he couldn’t see down the trail. The temperature was over 100 degrees, with the August humidity making it feel even hotter.

“I moved over to get out of the way of some Cat 1 racers, and my whole body cramped up. It stopped me in my tracks. I just fell over on the side of the trail,” he said. “It took me 20 minutes to get moving again. My race was over.”

Feldewert limped back to the staging area, where he tried to catch his breath but couldn’t. “A guy asked if he could dump water on me, and that about sent me into shock,” Feldewert said. “I sat there for 45 minutes with that 1,000-yard stare before I could get up and move again.”

Thinking the worst had passed, he shuffled to his car and drove home, even though he was still experiencing vision problems and had a bad headache.

“At home, I cramped up again and basically had to crawl into the house,” Feldewert said. “My wife ran and got electrolytes and ice packs for me. Three or four hours later, I ended up OK, but ever since then, it happens easier. It’s something I always have to watch for now.”

It was a bad case of heat exhaustion that might have been worse if Feldewert, who grew up on a farm and works in the construction business, wasn’t accustomed to being active outside in hot, humid weather. Still, no one is completely safe.

“I pay closer attention to what I drink, how much I drink now,” he said. “And I always carry gels with high sodium content. But it’s still not a surefire bet.”

Feldewert learned the hard way, but you don’t have to. Here’s a primer on the most common maladies that face outdoor athletes and recreationalists in summer — and how to deal with them.

All of us know that wearing sunscreen is important. “Remember the areas where you don’t think of getting sunburnt, like your lips,” said Dr. Matt Lytle, owner and clinical director of Precision Health Group, who treats a lot of athletes at his practice. “Any time you towel off, put the sunscreen back on, and make sure you’re not taking any medication that makes you more sensitive to sunlight.”

  • Prevention: Slosh on the sunscreen, SPF 15 or higher, and limit your time in direct sunlight. Wear protective clothing and a hat.
  • Symptoms: Red, inflamed skin that’s sensitive to heat and touch.
  • Treatment: Take a cool bath, then apply sunburn cream or Aloe Vera gel.
  • Get Help: If you notice any weird coloration, the burn blisters, or if the victim suffers delirium or unconsciousness.

Anyone can tell you the best way to avoid dehydration: Drink lots of water. Just don’t wait too long to do it. “The secret is to hydrate the day before. Typical rule of thumb is half your body weight in ounces,” said Lytle. “You can’t go into an activity and replace what you don’t have.” Limit beverages with diuretics, like caffeine and alcohol, or drink extra water to compensate.

  • Prevention: Keep the water flowing continually when you’re active outdoors.
  • Symptoms: Like a hangover — bad headache, dry mouth and lips, low urine output.
  • Treatment: Move out of the heat, lie down and sip cool water.
  • Get Help: If the sufferer is disoriented, vomits repeatedly or shows signs of shock (clammy skin, weak pulse, shallow breathing).

Like dehydration, it sounds simple to avoid: Feel overheated? Find someplace cool to rest. But heat exhaustion can happen fast, when your body accumulates so much heat so rapidly that you can’t get rid of it. Wearing a hat and light clothing can help. However, the sun doesn’t have to be hitting you for heat exhaustion to occur; very hot and humid conditions are also risky.

  • Prevention: Slow down outdoor activities; dress in cool clothes; take frequent breaks (indoors if possible).
  • Symptoms: Elevated body temperature, headache, dizziness, sweating stops.
  • Treatment: Wet down and fan yourself, or hop in the shower. Sip cool water.
  • Get Help: “When you start going down this road, the best course of action is to seek medical attention and get an IV,” said Lytle.

It’s the next, worse progression of heat exhaustion, with the symptoms just getting worse. Don’t mess around here; heat stroke can be fatal. Call 911.

Bugs are naturally attracted to sweaty people in bright, primary colors. So, wear light-colored clothes and use repellant. In general, and despite the media coverage, the risk of insect-spread diseases — West Nile virus, Lyme disease — is low in Missouri, but be sure to do bug checks after each outing and keep an eye on any suspicious bites or stings.

  • Prevention: Slather on insect-repellant lotion (better than spray or liquid); wear light colors; eschew flowery scents.
  • Symptoms: Itching, redness and swelling near the site of the bite or sting.
  • Treatment: Remove stinger (if possible), wash with soap and warm water. Antihistamine tablets can help reduce symptoms.
  • Get Help: If the person experiences abnormal swelling or rash, difficulty breathing or fainting, weird pains or nerve signs.

In Missouri, we’re mostly talking about poison ivy — poison oak or poison sumac to a lesser degree. Most of our trails are kept pretty clear, so it’s best to stay on track and not wander. Poisonous plants are usually worse in the spring and summer, but can turn bright colors in the fall, making them harder to identify and more attractive.

  • Prevention: “Look the plants up online and see what they look like, then stay away from them,” said Lytle.
  • Symptoms: Red, swollen, itchy rash accompanied by small blisters.
  • Treatment: Wash the area you suspect to be infected with cool water as soon as possible. Apply calamine lotion or hydrocortisone cream.
  • Get Help: If the rash covers a large area or doesn’t get better in a few days, or if the blisters begin to ooze.

Most of us think of it as a “kid thing,” but this infection caused by bacteria growing in the ear canal can keep you landlocked for a week or longer.

  • Prevention: If you’re prone to this condition, use over-the-counter swimmer’s eardrops when you get out of the water, and then dry your ears. Buy a swim mask with ear protection.
  • Symptoms: Itching, ear pain, loss of hearing.
  • Treatment: If you think you’re developing an infection, use the drops again. If it doesn’t improve by the next morning, see a doctor. Take antihistamine and use antibiotic eardrops.
  • Get Help: As fast as you can, so you can get back in the water sooner.

Author: Brad Kovach is the editor of Terrain magazine.