RELATIONSHIP BETWEEN MOOD STATE AND OXYGEN SATURATION DURING RESIDENCE AT HIGH ALTITUDE

Abstract

Following rapid ascent to high altitude (HA), arterial oxygen saturation (SpO2) is decreased due to the low partial pressure of oxygen, but increases over the next 6–10 days as ventilation increases. Likewise, mood state is negatively influenced during the acute phase of HA exposure but improves after 5–7 d of HA exposure paralleling the improvements in SpO2. PURPOSE: The purpose of this research was to determine if interindividual differences in mood state during residence at HA were related to the degree of hypoxemia (SpO2) in subjects exposed to 4,300 m for 21 d. METHODS: Sixteen male subjects, who were part of a study evaluating the effect of energy deficit on performance at high altitude, were rapidly transported to 4,300 m where they remained for 21 d. Among other tests, SpO2 and mood were measured at sea level (SL) and at HA on days 2, 4, 10 & 21 of exposure. Oxygen saturation was determined using a Nonin 8600 Pulse Oximeter. Mood states were measured by use of the Profile of Mood Status Bi-Polar Form (POMS-BI). The POMS-BI measures 6 subjective bi-polar mood states. The mean of all 6 bi-polar constructs represents “Global” mood. Pearson's correlation coefficient was determined between SpO2 and each mood construct at SL and d 2, 4, 10 & 21 at HA. RESULTS: As expected, at SL, moods showed no significant correlation with SpO2 in any construct. SL interindividual differences in SpO2 were small. Upon HA exposure, mood decreased significantly (P ≤ 0.05) in all constructs during days 2 and 4, returning to baseline values within 5–7 d of residence at HA. Similarly, SpO2 decreased upon acute exposure (80%) and gradually increased to 90% of SL values over the 21 d HA exposure. Significant correlation (P ≤ 0.05) was found between SpO2 and the mood constructs Agreeable-Hostile, Composed-Anxious, Confident-Unsure, Energetic-Tired, and Global only on day 4 of HA exposure. CONCLUSION: These data suggest that individual differences in mood state may be influenced by SpO2 during exposure to high altitude, but hypoxemia alone is not the only factor that modifies mood state. Supported by: The Borgenicht Program; Jeffress Memorial Trust; and U. S. Department of Defense.