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Acutely stressful situations can disrupt behavior and deplete brain norepinephrine and dopamine, catecholaminergic neurotransmitters. In animals, administration of tyrosine, a food constituent and precursor of the catecholamines, reduces these behavioral and neurochemical deficits. Using a double-blind, placebo-controlled crossover design we investigated(More)
Altitude exposures above 3,000 m produce changes in symptoms, moods, and cognitive/motor performance of unacclimatized individuals and should produce graded effects on these parameters as elevation and duration are increased. This study examined effects on these parameters as a function of altitude level and duration of exposure by administering(More)
Cognitive function at simulated altitude was investigated in a repeated-measures, within-subject study of performance by seven volunteers in a hypobaric chamber, in which atmospheric pressure was systematically lowered over a period of 40 d to finally reach a pressure equivalent to 8,845 m, the approximate height of Mount Everest. The portable cognitive(More)
Ascents above 4,000 m adversely affect symptoms, moods, and performance and cause acute mountain sickness (AMS). It is assumed that individuals afflicted with AMS will be more susceptible to changes in these other parameters; however, previous studies have suggested that their time courses are different. This investigation analyzed the relationships between(More)
This study examined the effects of dexamethasone and exposure to high terrestrial altitude on cognitive performance, affect, and personality. Cognitive performance was evaluated by five cognitive tasks, affect was evaluated by the Clyde Mood Scale and the Multiple Affect Adjective Check List, and personality was examined using the Minnesota Multiphasic(More)
Personal anecdotes suggest that ascent to high altitude can cause mood changes such as depression, apathy, and drowsiness. Observed behaviors at high altitude indicate that people can become more euphoric, irritable, or argumentative. Since there are few systematic and quantitative studies assessing the effects of altitude on mood, this study compared moods(More)
This 9 month prospective study, conducted at the US Army Sergeants Major Academy (USASGMA), examined the association of selected psychological variables (e.g., measures of tension/anxiety, sleep disturbance, Type A behavior pattern) with injury occurrence and physical performance in 126 soldiers. ANOVA and logistic regression analyses revealed significant(More)
This study describes associations between age, physical training and measures of muscle and cardiorespiratory endurance. The subjects were 5079 healthy male soldiers aged 18-53 years from 14 Army installations in the United States. The subjects completed as many push-ups as possible in 2 min, as many sit-ups as possible in 2 min, and performed a timed(More)
Self-rated moods were determined twice daily with the Clyde Mood Scale on 35 human subjects at 200 m (baseline) during a study concerned with evaluating the efficacy of staging plus acetazolamide (treatment) for the prevention of acute mountain sickness (AMS). Mood states also were determined on all subjects at 4300 m (Pikes Peak, Co) and on 18 of these(More)
Normal acid-base status of arterial blood (pHa =7.40, PaCO2=38.1 Torr) was demonstrated for conscious, restrained squirrel monkeys when environmental stimuli were minimized and monkeys are habituated to experimental procedures. These results indicate the potential for using squirrel monkeys in experiments in which normal acid-base status is a significant(More)
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