Psychological mood states have been shown to affect performance of ultramarathoners. To investigate differences between finishers and nonfinishers and mood changes associated with competing in an ultramarathon, mood states of 14 men were examined before and after the competition. The Profile of Mood States was administered pre-, post-, 1 wk., 1 mo., and 3 mo. postrace. Three mood states showed significant differences across time. Tension was higher prerace than at any time postrace. Vigor was lower immediately postrace and showed a gradual return to prerace levels. Fatigue was higher immediately postrace but returned to prerace levels by 1 wk. Changes in mood states may persist for up to one month following sustained physical performance in the ultramarathon. These changes in mood states may adversely influence ability to perform unless adequate recovery time is permitted prior to resuming training and competing.

Soldier performance on simple visual, auditory, and psychomotor tasks has been shown to be impaired by the bulkiness of combat clothing. Since rifle marksmanship is a complex task requiring the coordination of simple sensory and psychomotor skills, it was hypothesized that bulky combat clothing would also impair this task which is so critical to successful soldier performance and survival. Each of 30 male soldier volunteers, matched on rifle marksmanship ability, was assigned to one of three clothing conditions of increasing bulk: battle dress uniform, fighting load, or MOPP-IV chemical protective clothing. After four days of practice on the Weaponeer M16 rifle simulator, soldiers were assessed on marksmanship for pop-up targets (in both rifle supported and unsupported conditions) while dressed in the respective combat clothing. Results of a 3 × 2 (clothing × rifle support) analysis of variance showed that (a) regardless of clothing condition, marksmanship was significantly better when the rifle was supported than when it was not supported; and (b) rifle marksmanship was significantly poorer under the MOPP-IV chemical protective clothing condition than under either the fighting load condition or the battle dress uniform condition. The impairment while wearing MOPP-IV is likely due to the awkwardness in obtaining a rapid and proper sight alignment with the MOPP-IV gas mask.

Diphenhydramine causes drowsiness and performance decrements in some tasks whereas terfenadine generally does not. This study examined central nervous system (CNS) differences in response to the administration of diphenhydramine (50 mg) and terfenadine (60 mg) up to 3 h after drug administration. Two evoked potential measures, the Brainstem Auditory Evoked Potential and the Pattern Reversal Evoked Potential (PREP), assessed CNS function. Other measures of CNS function, cognitive performance and subjective states administered included Critical Flicker Fusion, the Baddeley Grammatical Reasoning Test, Digit Symbol Substitution, the Profile of Mood States, and the Environmental Symptoms Questionnaire. Significant increases in PREP latencies (N75, P100 and N145) occurred after orally ingesting diphenhydramine. No other significant drug effects were observed. The significant increase in the PREP latencies indicate diphenhydramine’s presence in the cerebral cortex results in a slowing of visual information processing. The lack of significant findings for terfenadine is probably a result of its difficulty in penetrating the blood-brain barrier.

This study assessed the effects of nerve agent antidote (atropine/2-PAM chloride versus saline placebo) and heat-humidity (95 degrees F/60% RH versus 70 degrees F/30% RH) on repeated performance of militarily relevant psychological tasks while wearing the battle dress uniform (BDU) and while wearing chemical protective clothing (MOPP-IV). All BDU heat sessions (6 hours) were completed, but with some task impairments and a few subjective reactions. MOPP-IV heat sessions could not be continued beyond 2 hours; all tasks were impaired and subjective reactions were numerous and severe. Atropine/2-PAM significantly shortened endurance time for heat sessions in MOPP-IV.

The purpose of this study was to evaluate the effects of sentry duty time on the soldier's speed of detection of visually presented targets, his ability to hit targets (rifle marksmanship), and his mood. Prior to the test day, each of eight subjects was given five days of training on the Weaponeer Rifle Marksmanship Simulator and was familiarized with the targets to be presented during testing. The test session lasted three hours, during which time the subject assumed a standing foxhole position and monitored the target scene of the Weaponeer. The Weaponeer M16A1 modified rifle lay next to the subject at chest height. When a pop-up target appeared, the subject pressed a telegraph key, lifted the rifle, aimed, and fired at the target. Speed of target detection was measured in terms of the time required by the subject to press the telegraph key in response to the presentation of the target. Marksmanship was measured in terms of number of targets hit. Target detection time and rifle marksmanship were averaged every 30 minutes. At the end of the test session, the subject completed the Profile of Mood States rating scale. The results showed that target detection time deteriorated with time on sentry duty; impairments were not evident within the first hour but were clearly evident by 1.5 hours. Marksmanship remained constant over time; soldiers were just as accurate in hitting the targets at the end of the 3 hours of sentry duty as they were at the beginning. Whereas the soldier's predominant mood during baseline practice sessions was one of vigor, during sentry duty the predominant mood was one of fatigue. The results of this study suggest that sentry duty performance may be optimized if it is limited to one hour or less.