Blood pressure before high altitude exposure: are all individuals healthy with controlled arterial blood pressure?

Background: The increasing accessibility of high altitudes due to modern lifts has led to rise in individuals reaching high elevations without acclimatization or medical screening. Acute exposure to hypobaric hypoxia induces hemodynamic and metabolic stress, increasing blood pressure (BP) and heart rate while reducing oxygen saturation. These effects are particularly concerning for individuals with preexisting cardiovascular diseases.

Methods: We conducted an observational cross-sectional study at the base station (1300 m) of the Skyway Monte Bianco cable car, evaluating the demographic and clinical characteristics of unselected participants before ascent. Data were collected via a biometric multiparametric recording system (Keito K9), measuring SpO2, heart rate, BP, body composition, and medical history.

Results: A total of 1930 individuals (56% men) participated but anamnestic data were available in 1174 volunteers. Among them, 18% had history of cardiovascular disease, predominantly hypertension (16%). SBP at least 135 mmHg was found in 11.1% of participants, with 4.3% presenting values at least 150 mmHg. The prevalence of individuals with hypertension above the reference limits was higher in cardiac patients. Cardiovascular patients were older, heavier, and had higher BP compared to healthy individuals. Interestingly, no differences in altitude exposure frequency were observed between groups.

Conclusion: Our findings indicate that a significant proportion of individuals, including those with cardiovascular disease, reach low altitudes with BP above the reference limits. Given the potential risks associated with hypoxia-induced sympathetic activation, improved screening and preventive strategies should be considered for high-altitude tourism. Further research is needed to assess acute BP variations at different altitudes and their implications for cardiovascular risk.