Blood Pressure and High Altitude: An Observational Cohort Study of Hypertensive and Nonhypertensive Himalayan Trekkers in Nepal
Bibliographic record
Abstract
Hypertension is the most common cardiovascular disease among those recreating at high altitude. Previous studies with smaller, more homogenous participant pools have demonstrated increases, decreases, and no change in blood pressure (BP). We sought to characterize how BP changes with altitude on both a population-wide and individual level in normotensive (NTN) and hypertensive (HTN) trekkers in Nepal. Trekkers in the Solukhumbu Valley of Nepal, aged 18 years and older, were recruited at 2860 m. They reported demographic information, medical history, and medications. Resting BP was recorded at 2860 m, 3400 m, and 4300 m on ascent and descent. Responses were compared between NTN and HTN subjects and across altitudes. We enrolled 604 NTN and 60 self-reported HTN trekkers. At 2860 m, mean systolic BPs (SBP) in NTN and HTN trekkers were elevated relative to self-reported home measurements (n = 303, mean difference = 9 mm Hg [95% CI 5-13], P < .05). Mean SBP did not differ between altitudes on ascent or descent (P > .05) but was higher in HTN vs NTN subjects at each altitude (P < .05). However, we observed large interindividual variability. Between 2860 m and 3400 m, the majority (60%, n = 284) of NTN SBPs did not change, while 21% (n = 102) increased >10 mm Hg and 19% (n = 91) decreased >10 mm Hg. The pattern was similar in NTNs between 3400 m and 4300 m: (65% [n = 202] no change, 21% [n = 65] increased, 15% [n = 46] decreased). A greater proportion of HTN trekkers had SBP decreases between 2860 m and 3400 m (45% [n = 19] no change, 19% [n = 8] increased, 36% [n = 15] decreased) and between 3400 m and 4300 m (44% [n = 10], 26% [n = 6], 30% [n = 7]), respectively. In most individuals, with and without HTN, BP is likely to change less than 10 mm Hg at altitudes up to 4300 m. In general, travelers, including those with well-controlled HTN, may be reassured that their blood pressure will remain relatively stable at high altitude.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".