Active Ascent Does Not Alter Mood State Compared To Passive Ascent Following Ascent To 3600 m

PURPOSE: Mood state is known to change following acute exposure to high altitude (HA) but it is unknown whether active ascent exacerbates the negative mood state typically associated with ascent to HA. The purpose of this study was to examine changes in mood state following active and passive ascent to 3600 m. METHODS: Forty-one healthy unacclimatized Soldiers (n = 41, mean ± SD; age = 26 ± 5 yr; body weight = 83.5 ± 11.6 kg; VO2max = 47.9 ± 5.5 ml · kg−1 · min−1) were tested at sea level (SL) in Ft. Leonard Wood, MO, flown to Taos Ski Valley, NM (2845 m) where they arrived around ~1400 and then either hiked (n = 21; 5.0 km, 15.5% mean grade) or were driven (n = 20; 30-min drive) to a HA ski patrol facility located at 3600 m where they resided for the next 4 days. Energy expenditure during ascent was assessed using an ankle accelerometer (Actical, Respironics, Inc.). Seven mood states (anger, anxiety, depression, fatigue, happiness, vigor, and restlessness) were assessed using the Automated Neuropsychological Assessment Metrics Mood Scale in the morning (~0900) at SL, and following ~19 h at HA (HA2), and ~ 43 h at HA (HA3). RESULTS: The active group expended a greater (P < 0.05) amount of energy (745 ± 435 kcal) than the passive group (55 ± 10 kcal) during ascent. There were no differences in mood state between groups so data were combined. Anger and anxiety increased (P < 0.05), respectively, from SL (0.04 ± 0.11; 0.07 ± 0.17) to HA2 (0.35 ± 0.74; 0.30 ± 0.56) and decreased (P < 0.05) from HA2 to HA3 (0.20 ± 0.47; 0.09 ± 0.32). Depression and fatigue increased (P < 0.05), respectively, from SL (0.02 ± 0.09; 0.29 ± 0.31) to HA2 (0.30 ± 0.64; 1.30 ± 1.17) and decreased (P < 0.05) from HA2 to HA3 (0.06 ± 0.22; 0.70 ± 0.89). Happiness and vigor decreased (P < 0.05), respectively, from SL (3.64 ± 1.30; 2.23 ± 1.32) to HA2 (2.91 ± 1.64; 1.86 ± 1.30) and remained unchanged from HA2 to HA3 (2.85 ± 1.64; 1.84 ± 1.46). Restlessness increased (P < 0.05) from SL (0.10 ± 0.22) to HA2 (0.52 ± 0.97) and decreased (P < 0.05) from HA2 to HA3 (0.22 ± 0.51). CONCLUSION: Active compared to passive ascent did not impact mood but negative mood state and fatigue were increased while positive mood state was decreased following rapid ascent to HA when both groups were combined. Authors’ views not official U.S. Army or DoD policy. Funding: USAMRDC