Introduction
Hypertension has been suggested as a possible risk factor for acute mountain sickness (AMS).
Objective
To determine the relationship between blood pressure (BP), hypertension (HTN), and AMS in trekkers in Nepal’s Solukhumbu Valley.
Methods
An observational cohort study of subjects with and without hypertension. BP, heart rate (HR), oxygen saturation (SpO2), and Lake Louise Score for AMS (LLS) were measured at 2800 m, 3400 m, and 4300 to 4400 m in trekkers in Nepal. Subjects with HTN were defined as those with a self-reported diagnosis of hypertension. AMS was defined as LLS ≤3 with headache. Mean arterial pressure (MAP) was estimated by the formula: MAP = ([(2 × diastolic] + systolic) / 3.
Results
We enrolled a total of 670 subjects; those with no HTN (NTN, n = 604), HTN (n = 60), or reported borderline HTN (BTN, n = 6). BP values were similar in HTN and BTN groups, and these were treated as one group for the analyses. A total of 528 subjects (HTN = 48) were re-evaluated at 3400 m and 365 subjects (HTN = 30) at 4400 m. The prevalence of AMS was less in those with HTN vs those without (2% vs 11% at 3400 m, 3% vs 14% at 4400 m, P > .05). There was no relationship between systolic BP, diastolic BP, or estimated MAP and AMS (P > .05) at any altitude. Taking any BP medication appeared protective at 3400 m (P < .05), but not at 4400 m (P > .05). SpO2 was associated with AMS at 4400 m (P < .05) but not at 3400 m (P > .05).
Conclusions
History of HTN was associated with a decreased risk of AMS in this large cohort study of trekkers; however, blood pressure values were not related to AMS. No participant taking blood pressure medication developed AMS at 3400 m.
Funding
WMS Hultgren Grant (2014).