This study investigated changes in information-processing efficiency that occur when physical fitness improves. Information-processing variables were Sternberg's memory-scan rate, Posner's name-access time, the Cattell Culture Fair Intelligence Test, and numbers of words remembered from word lists. At present and posttest 10 to 12 wk. later, 66 adults between the ages of 18 and 48 yr. took all cognitive tests and rode a bicycle ergometer to estimate physical fitness. A 2 X 2 (improved/stable fitness groups by pretest/posttest trials) analysis of variance with repeated measures indicated that the group who improved 15% or more in physical fitness improved significantly more on the name-access time than the group whose fitness remained stable. There was a trend toward improvement in memory-scan rate and number of words remembered on the first word trial by people who became more fit. The results may have implications for assessment and training of personnel in occupations where speeded perception and responses are required.