hosts the International HAPE Database, a database of previous HAPE sufferers worldwide who might consider participating in future research studies.

Lake Louise Consensus on Acute Mountain Sickness 2018

The original Lake Louise Score (LLS) was devised by a consensus process and originally published in 1993. Since then it has been an invaluable tool for research into acute mountain sickness (AMS). In recent years, however, research has suggested that sleep disturbance, a diagnostic criterion in the original LLS, is, in fact, a separate entity from AMS. As such in 2018 a newly revised Lake Louise Acute Mountain Sickness Score was agreed by consensus and published1. This revised score removed sleep disturbance and also recommended the use of an optional AMS clinical functional score, where the study design allowed.

This new score represents a significant change in the field of high altitude research and should be the standard assessment of AMS in studies involving the condition.

2018 Lake Louise Acute Mountain Sickness Score
Symptom Description Score
None at all 0
A mild headache 1
Moderate headache 2
Severe headache, incapacitating 3
Gastrointestinal symptoms
Good appetite 0
Poor appetite or nausea 1
Moderate nausea or vomiting 2
Severe nausea and vomiting, incapacitating 3
Fatigue and/or weakness
Not tired or weak 0
Mild fatigue/weakness 1
Moderate fatigue/weakness 2
Severe fatigue/weakness, incapacitating 3
No dizziness/light-headedness 0
Mild dizziness/light-headedness 1
Moderate dizziness/light-headedness 2
Severe dizziness/light-headedness, incapacitating 3
AMS Clinical Functional Score
Overall, if you had AMS symptoms, how did they affect your activities?
Not at all 0
Symptoms present, but did not force any change in activity or itinerary 1
My symptoms forced me to stop the ascent or to go down on my own power 2
Had to be evacuated to a lower altitude 3


  1. Hall, D. P. et al. Network Analysis Reveals Distinct Clinical Syndromes Underlying Acute Mountain Sickness. PLoS ONE 9, e81229 (2014).
    [pre-print version published online at arXiv is available here]
  2. Macinnis, M. J., Lanting, S. C., Rupert, J. L., Koehle, M. S. Is poor sleep quality at high altitude separate from acute mountain sickness? Factor structure and internal consistency of the Lake Louise Score Questionnaire. High Alt. Med. Biol. 14, 334–337 (2013).
  3. Roach RC, Hackett PH, Oelz O, Bärtsch P, Luks AM, MacInnis MJ, Baillie JK, and the Lake Louise AMS Score Consensus Committee, The 2018 Lake Louise Acute Mountain Sickness Score. High Alt Med Biol. 2018;19: 4–6. doi:10.1089/ham.2017.0164