Close-up macro photograph of a detailed snowflake resting on frost, symbolising cold exposure and hypothermia risk during extreme endurance events.
20 Feb 2026

Hypothermia After Extreme Sports (Adult)

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Understanding Hypothermia

Hypothermia happens when your body temperature drops below normal (below 35°C). The accepted classification system tells us that mild hypothermia occurs between 33-35°C, moderate at between 28-33°C, and severe is <28°C.

During endurance or extreme events this can occur due to:

  • Cold air or water exposure
  • Wind and rain
  • Wet clothing
  • Long event duration
  • Fatigue and low energy stores

As your body cools, it struggles to generate enough heat. This affects muscle strength, coordination, thinking, and in severe cases, the heart.

Today your temperature and symptoms improved with warming. You are now stable.

You developed signs of cold stress during the event.

You were assessed and rewarmed using passive warming measures.

You responded appropriately and were deemed safe to leave the medical area.

It is common to experience:

  • Shivering (may persist for a few hours)
  • Fatigue or weakness
  • Headache
  • Mild nausea
  • Stiff muscles
  • Feeling “washed out”

Most people feel significantly better within 12–24 hours, though fatigue can last 1–2 days.

It is normal to feel tired tomorrow.

It is not normal to:

  • Become confused
  • Have worsening drowsiness
  • Develop chest pain
  • Stop shivering despite still feeling cold
  • Rest.
  • Stay in a warm environment.
  • Wear dry, layered clothing.
  • Eat warm meals.
  • Drink warm fluids (avoid alcohol).
  • Avoid strenuous exercise for at least 24 hours.
  • Do not return to cold water or prolonged exposure today.

For future events:

  • Use appropriate thermal layers.
  • Keep spare dry clothing available.
  • Increase calorie intake before and during long events.
  • Avoid stopping for long periods while wet.
  • Monitor weather conditions closely.
  • Know your personal limits.

If participating in open-water or alpine events, consider:

  • Neoprene thermal protection (where allowed)
  • Windproof outer layer
  • Buddy monitoring

⚠️ Call 000 or go to the nearest Emergency Department if:

  • You become confused or unusually drowsy
  • You collapse or faint
  • You develop chest pain or palpitations
  • You stop shivering but still feel cold
  • You have uncontrolled shaking
  • Your speech becomes slurred
  • You cannot stay awake

See your GP within 48 hours if:

  • You still feel unwell
  • Fatigue is severe
  • You have ongoing nausea or weakness
  • You have any concerns about your recovery

You do not need routine follow-up if you recover fully within 24–48 hours.

Healthdirect Australia: 1800 022 222

You can also contact your GP or local Emergency Department.

  • Brown DJ, Brugger H, Boyd J, Paal P. Accidental hypothermia. N Engl J Med. 2012 Nov 15;367(20):1930-8. doi: 10.1056/NEJMra1114208. Erratum in: N Engl J Med. 2013 Jan 24;368(4):394. PMID: 23150960.
  • Paal P, Pasquier M, Darocha T, Lechner R, Kosinski S, Wallner B, Zafren K, Brugger H. Accidental Hypothermia: 2021 Update. Int J Environ Res Public Health. 2022 Jan 3;19(1):501. doi: 10.3390/ijerph19010501. PMID: 35010760; PMCID: PMC8744717.
  • Musi ME, Sheets A, Zafren K, Brugger H, Paal P, Hölzl N, Pasquier M. Clinical staging of accidental hypothermia: The Revised Swiss System: Recommendation of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Resuscitation. 2021 May;162:182-187. doi: 10.1016/j.resuscitation.2021.02.038. Epub 2021 Mar 3. PMID: 33675869.
  • Dow J, Giesbrecht GG, Danzl DF, Brugger H, Sagalyn EB, Walpoth B, Auerbach PS, McIntosh SE, Némethy M, McDevitt M, Schoene RB, Rodway GW, Hackett PH, Zafren K, Bennett BL, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update. Wilderness Environ Med. 2019 Dec;30(4S):S47-S69. doi: 10.1016/j.wem.2019.10.002. Epub 2019 Nov 15. PMID: 31740369.
  • Castellani JW, Young AJ. Human physiological responses to cold exposure: Acute responses and acclimatization to prolonged exposure. Auton Neurosci. 2016 Apr;196:63-74. doi: 10.1016/j.autneu.2016.02.009. Epub 2016 Feb 21. PMID: 26924539.

Based on current Australian sports and environmental medicine guidance.
Version 1.0
Review due: February 2027
Annual review cycle.

NB: This information has been prepared with reference to the most up to date Australian standards and guidance in relevant sports medicine fields. It is prepared in good faith, however is only intended for use as explicitly directed by a DeployED health practitioner. It does not replace medical advice, nor does it purport to be perfect. If you have any doubts about the advice here, please consult your own doctor. If you have not been sent here by us, then this is not for you and DeployED accepts no responsibility for any outcomes which come to pass from your use of this information.

Follow Dr Stuart McLay:

Emergency Physician

Dr Stuart McLay is passionate about the delivery of exceptional care, everywhere. He is the founder of DeployED, a Fellow of the Australasian College of Emergency Medicine (FACEM - an Emergency Physician), a Core trainee of the College for Intensive Care Medicine, and a Mass Gathering Medicine / Expedition Medicine enthusiast. He's also a husband to 1, and father to 3, and a great annoyance to many.