Exercise performance and symptoms in lowlanders with COPD ascending to moderate altitude: randomized trial.

Furian M; Flueck D; Latshang TD; Scheiwiller PM; Segitz SD; Mueller-Mottet
S; Murer C; Steiner A; Ulrich S; Rothe T; Kohler M; Bloch KE.

International Journal of Copd. 13:3529-3538, 2018.

Objective: To evaluate the effects of altitude travel on exercise
performance and symptoms in lowlanders with COPD.
Design: Randomized crossover trial.
Setting: University Hospital Zurich (490 m), research facility in
mountain villages, Davos Clavadel (1,650 m) and Davos Jakobshorn (2,590m).
Participants: Forty COPD patients, Global Initiative for Obstructive Lung
Disease (GOLD) grade 2-3, living below 800 m, median (quartiles) age 67 y
(60; 69), forced expiratory volume in 1 second 57% predicted (49; 70)
Intervention: Two-day sojourns at 490 m, 1,650 m, and 2,590 m in
randomized order.
Outcome measures: Six-minute walk distance (6MWD), cardiopulmonary
exercise tests, symptoms, and other health effects.
Results: At 490 m, days 1 and 2, median (quartiles) 6MWD were 558 m (477;
587) and 577 m (531; 629). At 2,590 m, days 1 and 2, mean changes in 6MWD
from corresponding day at 490 m were -41 m (95% CI -51 to -31) and -40 m
(-53 to -27), n=40, P<0.05, both changes. At 1,650 m, day 1, 6MWD had
changed by -22 m (-32 to -13), maximal oxygen uptake during bicycle
exercise by -7% (-13 to 0) vs 490 m, P<0.05, both changes. At 490 m, 1,650
m, and 2,590 m, day 1, resting PaO2 were 9.0 (8.4; 9.4), 8.1 (7.5; 8.6),
and 6.8 (6.3; 7.4) kPa, respectively, P<0.05 higher altitudes vs 490 m.
While staying at higher altitudes, nine patients (24%) experienced
symptoms or adverse health effects requiring oxygen therapy or relocation
to lower altitude.

Conclusion: During sojourns at 1,650 m and 2,590 m, lowlanders with
moderate to severe COPD experienced a mild reduction in exercise
performance and nearly one quarter required oxygen therapy or descent to
lower altitude because of adverse health effects. The findings may help to
counsel COPD patients planning altitude travel.