Some researchers have reported that moderate physical exercise improves cognitive function, and that exercise at high intensity beyond the optimal point attenuates performance, in an inverted U-relationship. The optimal intensity of physical exercise for cognitive function might be related closely to the anaerobic threshold. It has been regarded as an extremely useful index for effective training intensity in cardiorespiratory fitness. This review specifically addresses acute physical exercise around the anaerobic threshold in healthy subjects and its effects on task performance during or after exercise. We discuss physiological factors for the facilitating effect of moderate exercise on cognitive function, which indicates the initial basis in complicated mechanisms of the benefits of physical exercise on cognitive performance.

The duration of the enhancement of choice reaction task efficiency by physical exercise at lactate threshold was studied. After healthy male students completed the exercise or nonexercise (control) period for 10 min., they performed a three-choice reaction task for 20 min. The mean heart rate during the choice reaction task after the exercise was higher than that after the control period (p < .05). For average percentage of correct answers, there were no significant differences between the exercise and control conditions. The reaction time during the first 8 min. of the 20-min. choice reaction task after the exercise period was less than that after the control period and increased gradually thereafter. In conclusion, whereas the choice reaction time was improved by physical exercise at around lactate threshold, the positive effects were seen mainly in the early stages of the task.

We examined the effects of prolonged voluntary wheel-running on skeletal muscle functional and/or structural characteristics in rats. Male Sprague-Dawley rats (5 weeks old) were divided into five groups: (1) 15W-SC, sedentary controls housed in normal plastic cages until age 15 weeks; (2) 15W-VE, housed in a voluntary-exercise (running-wheel) device equipped with housing space until age 15 weeks; (3) 35W-SC, housed in normal plastic cages until age 35 weeks; (4) 35W-VE, housed in the voluntary-exercise device until age 35 weeks, and (5) 35W-MVE, housed in normal plastic cages until age 15 weeks, then in the voluntary-exercise device from age 16 weeks to 35 weeks ("middle age"). At the end of each rat's experimental period, the plantaris muscle was dissected from each hindlimb for analysis of the muscle's functional and/or structural characteristics. Total running distance was similar in 15W-VE and 35W-VE, both being significantly greater than in 35-MVE. The percentage of type IIb myosin heavy chain isoform was significantly lower in each VE group than in the corresponding SC group. This shift from type IIb was significantly greater for 35W-VE than for the other VE groups, which were similar to each other. The cross-sectional area of type IIx fibers was significantly greater in 35W-VE than in 35W-SC, but this was not true for 15W-VE versus 15W-SC or for 35W-MVE versus 35W-SC. No significant difference in citrate synthase activity was detected between any VE group and the corresponding SC group. These results suggest that a prolongation of voluntary wheel-running leads to some advantageous enhancements of functional and/or structural characteristics in rat plantaris.

Quantitative ultrasound (QUS) parameters of the calcaneus and bone resorption markers predict osteoporotic fractures. High levels of physical activity have positive effects on bone health. The purpose of this cross-sectional study was to investigate the effects of daily walking activity (number of steps taken), as an outcome of physical activity, on QUS parameters of the calcaneus and urinary deoxypyridinoline (DPD) in elderly Japanese women. The subjects were 113 postmenopausal women aged 60-85 years. The speed of sound (SOS), broadband ultrasound attenuation (BUA), and the stiffness index (Stiffness) of the calcaneus were measured with A-1000 (GE-Lunar, USA). Spot urine samples were collected between 09:00 and 10:00, and the levels of urinary DPD were measured. The subjects were instructed to wear a pedometer during waking hours for 7 consecutive days. In univariate analyses, steps/day significantly decreased with aging (rϭϪ0.306, pϽ0.001). Steps/day showed significant positive correlations with SOS (rϭ0.252, pϽ0.01) and Stiffness (rϭ0.258, pϽ0.01). There was a significant decrease in DPD with steps/day (rϭϪ0.262, pϽ0.01). These effects of walking on QUS parameters and DPD remained significant after adjustment for confounding factors by multiple regression analyses. We conclude that high levels of walking activity may be effective in both maintaining the levels of QUS parameters and reducing bone resorption, and hence preserve bone health in elderly women. J Physiol Anthropol 27 (6) Huopio et al., 2004;Lee et al., 2002;Miller et al., 2002). In addition, high levels of bone turnover markers are related to an increased risk of osteoporotic fracture (Garnero et al., 1996(Garnero et al., , 2000. Krieg et al. (2006) reported that combining a bone resorption marker with a QUS parameter improves the prediction accuracy for patients at a high risk of fracture. Therefore, maintaining high QUS parameters and low levels in bone resorption markers could help in the prevention of osteoporotic fractures in elderly women.A (Iwamoto et al., 2002;Welsh and Rutherford, 1996;Woitge et al., 1998;Yamazaki et al., 2004) indicated that increased physical activity is effective in reducing the levels of bone resorption markers. Hoshino et al. (1996) reported that postmenopausal golf caddies had both higher QUS parameters and lower levels in bone resorption markers compared to sedentary controls. However, golf caddies are specific subjects with very high levels of occupational physical activity (they walk 5 miles a day and work 3 days a week for 2-20 years (Hoshino et al., 1996)), and no study has been carried out to investigate the associations of physical activity with both QUS parameters and bone resorption markers among the general elderly population.In most of the studies mentioned above, questionnaire-based assessments of physical activity were performed. As an alternative to this assessment, pedometers are a reliable way to monitor physical activity in healthy older adults without gait disorders (Cyarto et al.,...

In this cross-sectional study, we investigated the effect of daily walking steps on ultrasound parameters of the calcaneus in elderly Japanese women. The subjects were 143 community-dwelling elderly women aged 61-87 years (mean age 71.4+/-5.5 years). The speed of sound (SOS), broadband ultrasound attenuation (BUA) and the stiffness index (Stiffness) of the calcaneus were measured. Walking steps were recorded using a pedometer for 7 consecutive days as an outcome measure of physical activity. In univariate analyses, steps/day significantly decreased with aging. SOS, BUA and Stiffness showed negative correlations with age and positive correlations with weight. Linear relationships were not seen between any of the ultrasound parameters and daily walking steps. Then, the ultrasound parameters were adjusted for age and/or weight using multiple regression models, and the relationships between the adjusted ultrasound measurements and walking steps were examined using quadratic regression models. Walking activity up to approximately 12,000 steps/day was positively associated with the adjusted ultrasound measurements, above which additional walking steps had no positive effect. We conclude that daily walking steps may be suitable for evaluating the relationship between ultrasound parameters and physical activity in elderly women, but further research is needed to confirm the effect of daily walking steps on the rate of bone loss.