This research examined varying levels of physical activity and psychomotor and physiological function in variously active older men. Very active, moderately active, and low active participants were tested on simple (SRT) and choice reaction time (CRT), coincidence-anticipation timing (CAT), and [VO.sub.2]max. No significant differences for age or height were found, although percentage of fat, and weight were statistically different. Active groups were leaner and lighter. [VO.sub.2]max was significantly different between groups, as physically active groups yielded greater values. SRT and CAT also yielded significantly different results with more active participants showing better performance. No between-groups significant differences resulted for CRT. Generally, increased levels of physical activity were related to superior physiological outcomes and improved psychomotor performance.
Key words: age, coincidence-anticipation timing, reaction time, [VO.sub.2]max
Research over the past 100 years has determined that behavioral slowing is a characteristic of increasing age through adulthood (Birren & Fisher, 1995). These declines are so prevalent they have been described as "profound" (Spirduso, 1995, p. 185.) or "...the most robust phenomenon seen in research on aging" (Birren & Fisher, 1991, p.1). The topic has created considerable interest among the research community, as the behavioral slowing appears to limit related components such as fluid intelligence and the precognitive capacity for attention (Birren & Fisher, 1991) in addition to the direct impact on successfully completing daily living activities.
Considerable research has indicated that this slowing may be a function of both general (e.g., deterioration to the central nervous system, Walker, Philbin, & Fisk, 1997) and specific factors (e.g., movement planning or execution, Yan, Thomas, & Stelmach, 1998). Historically, some the most frequently cited specific decrements leading to the slowing include changes in neurotransmitter levels (Bortz et al., 1981; Fraioli et al., 1980; Wood, Stotland, Richard, & Rackham, 1980), declines in neural conduction velocity (Downie & Newell, 1961; Gilliatt, Goodman, & Willison, 1961; LaFratta & Canestrari, 1966; LaFratta & Smith, 1964; Mayer, 1963), or information processing speed (Salthouse, 2000). However, the relative contributions of general and specific factors are often overlooked in lieu of the more common all-or-none approach. In fact, recent methods partitioning age-related variance have indicated that large portions of the declines in behavioral slowing are shared with age-related effects of other variables (S althouse, 2000).
This raises interesting clinical questions about the causes of behavioral slowing and how it might be ameliorated. Cause has been attributed to such factors as life style, disease, occupation, educational level, ethnicity, and physiological capacity (Birren & Fisher, 1995). Understanding the relationship of factors such as health, exercise, or physical activity to the typical age-related declines in psychomotor speed is important. Considerable evidence shows that health and physical activity may be associated with age-related slowing (Birren & Fisher, 1995). For example, Earles and Salthouse (1995) studied participants between the ages of 18 and 87 years of age in relationship to self-rated health, sensory-motor speed, perceptual speed, and reaction time. Age was found to relate directly to all forms of speed examined, with self-reported health only partially mediating the slowing with age. Similarly, Era, Berg, and Schroll (1995) studied 75-year-old Nordic men and women by examining simple reaction time, mul tichoice reaction time, and movement time. More fit participants exhibited greater psychomotor speed. Baylor and Spirduso (1988) specifically studied older women who differed in their …