Observational study · Summer 2026
SAAS-10@CRM
Somatic Alertness and Acute Mountain Sickness: investigating sex-based differences in symptom reporting at the Capanna Regina Margherita (4,554 m)
Monte Rosa · Italian Alps
Somatic Alertness and Acute Mountain Sickness: investigating sex-based differences in symptom reporting at the Capanna Regina Margherita (4,554 m)
Acute mountain sickness (AMS) is measured via questionnaires — what you feel and report. But if men and women perceive and report symptoms differently, are you measuring biology or perception?
Some studies suggest a higher AMS prevalence in women, but the literature is conflicting. Hormonal and vascular sex differences may play a role — but that is just one explanation.
Previous IRT analyses on the Annapurna Circuit showed comparable scale functioning but a trend toward different gastrointestinal symptom reporting. Perceptual differences could partly explain the "sex gap".
We measure somatic alertness: the tendency to notice, interpret, and report bodily signals. If this differs between men and women, it could co-determine symptom scores.
AMS scores are a composite signal. This model shows how physiology, perception, and reporting style collectively determine the measurement outcome.
4,554 m hypobaric hypoxia, exertion, acclimatization status
SpO₂ drop, heart rate change, hyperventilation
Monitoring, catastrophic interpretation, behavioral response (SAAS-10)
LLS-total, AMS-C
Cross-sectional observational study. All measurements take place ≥ 4 hours after arrival at the hut, during the initial phase of symptom development.
A combination of demographic data, validated questionnaires, and non-invasive physiological measurements (7–10 min per participant).
Essential basic data: biological sex, age, and previous mountain experience (acclimatization history).
Somatic Alertness at Altitude Scale. Measures the tendency to notice, interpret, and report bodily signals.
International standard for AMS. Scores headache, gastrointestinal symptoms, fatigue, and dizziness.
Environmental Symptoms Questionnaire. Weighted calculation for cerebral mountain sickness symptoms.
Rating of Perceived Exertion. Separates exertion-related fatigue from hypoxia symptoms.
Peripheral oxygen saturation and heart rate via Nonin clinical pulse oximeter on the finger.
All adult mountaineers present at the Capanna Regina Margherita during the 2026 research season.
Participation is simple, voluntary, and takes only 9–12 minutes. Everything takes place in the hut.
The researcher explains the study and asks for participation
Scan the QR code on the poster in the hut or you will be approached by the researcher
Read the information and provide digital consent via Castor EDC
Complete the demographics, LLS, ESQ-III, BORG, and SAAS-10 digitally (~9 min)
Short non-invasive measurement with finger sensor (~2 min)
The primary analysis tests whether somatic alertness (SAAS-10) is associated with AMS severity, and whether this association differs between men and women.
The primary inference is based on two parallel regression models for the continuous outcome measures of mountain sickness severity: the Lake Louise Score (LLS) and the AMS-C score.
These models test the association between somatic alertness (SAAS-10) and AMS severity, adjusting for prespecified covariates: age, previous altitude experience, use of analgesics or acetazolamide, and physical exertion (Borg score).
Because the exact distribution of the outcomes is fully mapped only after data collection, the definitive statistical method (generalized linear modeling) is chosen based on the observed data properties. The Sex × SAAS-10 interaction term formally tests whether the relationship between somatic alertness and reported symptoms differs between men and women.
Logistic regression for exceeding diagnostic thresholds: LLS ≥ 3 + headache and AMS-C ≥ 0.7. Supportive, non-primary inference.
Initial validation: exploratory factor analysis (polychoric correlations), internal consistency, and SAAS-8 sensitivity analysis (excluding reversed items 9 and 10).