Heat Illness - 2019 Guidelines with Dr. Mel Otten

On today’s podcast, we are taking a new direction in talking with authors about their work and no better place to start than discussing the Wilderness Medical Society (WMS) 2019 Guidelines on Heat Illness with Dr. Mel Otten, Past President of the Wilderness Medical Society.

Guideline Timeline:

  • 2013 WMS releases first guidelines based on evidence rather than expert opinion

  • 2019 revisions with an emphasis on exertion relation heat illness in addition to updated research

Defining the Disease

  • 70,000 people killed in 2003 from a European heat wave

  • This will only be increasing as climate change becomes more tangible

  • Spectrum of disease, from self limited heat cramps, heat edema and heat syncope to heat exhaustion (typically exertional) and heat stroke

  • Heat Stroke = CNS involvement + 104 F core temperature

    • 10% mortality once it progresses to CNS involvement

    • Duration of exposure and temperature of exposure are both critical to mortality


  • Anything is better than nothing - your goal is 102 F core temp

  • Treat agressively based on what you have

    • Cold Water Immersion (in ice bath) is the most effective way to reduce core temperature

    • Ice packs apply to the palms and soles (highest vascular surface area)

    • Exposure and evaporative cooling (fans and misting)

Other Fast Heat Illness Facts

  • Shivering does a minimal amount of core warming and will not inhibit your cooling

  • Rectal temperature is the best initial measurement, if immersed, consider esophageal monitoring

  • Your body can acclimatize to hot environments - try 1 hour of exertion for 10-14 days before your activity, as can adapt your body to:

    • Sweat at a lower temperature

    • Increase the amount of sweat glands

    • Decrease the concentration of sodium in sweat

Guest Author Mel Otten, MD

Host Ryan LaFollette, MD