Anxiety as a factor in underwater performance

Thirty-two divers were divided into four groups. Each group made one dive to 6 m or 30 m in day or night conditions. Measures of manual dexterity, time estimation and cognitive performance were obtained on the surface and under water. Heart and respiration rate were monitored prior to water entry and during the dive. A self-report anxiety questionnaire was presented before and after the dive. Heart rate dropped under water in the 6 m groups and rose in the 30 m groups while respiration rate remained elevated throughout. Self-report anxiety fell in the 6 m groups and increased in the 30 m groups. A 14-30% decrement occurred in manual dexterity at 6 m and a 45-47% decrement at 30m. Cognitive performance improved at 6 m but there was a 26-36% decrement at 30 m. While time estimation varied widely on the surface all groups tended to overestimate a time standard under water in comparison with the surface. The results support the notion that anxiety is a contributory factor in the decrement of performance under water.