As one of the Seven Wonders of the World, Machu Picchu is a popular international destination. Being at high altitude and the physical demands of hiking in the region make acclimation to the change in altitude a challenge for individuals coming from low altitude. Understanding how individuals might respond to acclimation at various areas within the Sacred Valley region of Peru may be beneficial for electing specific logistics of a similar trip, particularly if physical exertion is planned.
PURPOSE: To identify the changes in heart rate (HR) and blood pressure during acute exposure to altitude and acute acclimation.
METHODS: Eight individuals (males = 3, 24.8 ± 5.4 years) living at low altitude recorded resting heart rate and blood pressure throughout the course of a 10-day trip in the Sacred Valley, Cusco, Peru. In addition, the subjects completed four Rockport Walk Tests (RWT): prior to travel (180 m), two moderate to high altitude locations (2792 and 3400 m), and return to low altitude (154 m). Repeated measures ANOVAs with post-hoc testing identified differences between RWT completion HR, time, and maximal oxygen estimation (VO2max) and also between resting HR and blood pressure during 9 different altitude changes.
RESULTS: The RWT had significant differences in estimated VO2max estimations between 3400 m (45.7 ± 1.1 ml·kg-1·min-1) and return to low altitude (154 m, 49.1 ± 1.6 ml·kg-1·min-1, p = .03) and HR from the RWT had differences between both low altitude tests and high altitude tests (differences ranged from 29.6 - 34.7 bpm, p < .05). There were no differences in RWT completion time. Resting HR was the only resting measure to show changes and only after the highest ascent (4830 m) was HR increased (p < .05) from prior travel measures (180 m) (+28.4 ± 4.5 bpm), 2792 m (+30.4 ± 4.5 bpm), 4300 m (+18.1 ± 2.4 bpm), and return to low altitude (+27.0 ± 4.2 bpm).
CONCLUSION: Both resting and exercising heart rates are affected by acute altitude exposure, despite several days of moderate to high altitude exposure. When planning trips to high altitude regions for short periods (≤ 10 days), elevated heart rates should be expected.