BackgroundRecent research highlights the importance of environment as a determinant of physical activity; however, evidence among Japanese is sparse. The aim of this study was to examine the association between perceived neighborhood environment and neighborhood walking for multiple purposes among Japanese.MethodsWe conducted a population-based, cross-sectional study of 1461 Japanese adults (age: 48.2 ± 14.1 years, men: 44.8%). Neighborhood environment and walking were assessed by a validated questionnaire. The odds ratio of active walkers was calculated in relation to environmental characteristics after adjustment for age, sex, and other potential confounders.ResultsParticipants were more likely to walk when they perceived that there was high residential density (odds ratio, 1.47; 95% confidence interval, 1.11–1.96), fair land use mix–diversity (1.37, 1.04–1.81), good walking/cycling facilities (1.56, 1.19–2.04), and attractive aesthetics (1.49, 1.14–1.95). Environmental factors associated with walking differed with respect to the purpose for walking. The environmental characteristics associated with walking for daily errands and with walking for commuting were similar, and included residential density and land use mix. Walking for leisure was associated with walking/cycling facilities, aesthetics, and traffic safety. Stratified analyses showed some sex-specific associations. Among women, there was an unexpected inverse association of leisure walking with both residential density and land use mix–diversity.ConclusionsThe association between neighborhood environment and walking differed by walking purpose. The results were generally consistent with those of studies conducted in Western countries, except for the association of high residential density and good land use mix–diversity with less leisure walking in women. These results suggest possible targets for environmental interventions to promote walking.

Physical exercise has been shown to increase adult neurogenesis in the hippocampus and to enhance synaptic plasticity. It has been demonstrated that these neuroprotective effects can be observed following aerobic exercise. However, it remains unknown whether plasticity molecules, such as brain-derived neurotrophic factor (BDNF) and cyclic AMP response element-binding protein (CREB), are expressed in the hippocampus following resistance exercise. We applied voluntary progressive-resistance wheel exercise (RE) for 14 days, and measured BDNF and CREB in the hippocampus. The Morris water maze was also performed to estimate learning and memory. Furthermore, we measured RE effects on mammalian target of rapamycin (mTOR) and 70-kDa ribosomal protein S6 kinase (p70S6K) mediating muscle protein synthesis in the soleus. As a result, we found that RE enhanced cognition and elevated BDNF and CREB expressions in the hippocampus. Also, RE activated the mTOR-p70S6K signaling pathway in the soleus. We found that phosphorylated mTOR and p70S6K were significantly positively correlated with BDNF expression. Our results indicated that resistance exercise drove the protein synthesis signaling pathway in the soleus and enhanced hippocampal synaptic plasticity-related molecules. These results suggest the beneficial effects of resistance exercise on cognitive function.

BackgroundThe perception of barriers to exercise is an important correlate of exercise participation. However, only a limited number of studies—mostly from Western countries—have attempted to describe the perceptions of barriers to exercise in specific population groups. This study examined the associations between sociodemographic attributes and perceived barriers to exercise in Japanese adults.MethodsA population-based cross sectional study of 865 participants (age: 20–69 years old, men: 46.5%) was conducted in 4 cities in Japan. Nine sociodemographic attributes (sex, age, location of residence, educational attainment, marital status, employment status, presence of dependents in the household, self-rated health, body mass index), along with exercise frequency and perception of barriers to exercise (discomfort, lack of motivation, lack of time, lack of social support, poor environment) were assessed by self-administered questionnaire.ResultsThe most strongly perceived barrier was lack of time. Five of 9 sociodemographic attributes were significantly related to certain types of perceived barriers. Participants who more strongly perceived barriers were younger, more highly educated, more likely to be employed, and had relatively poor self-rated health and a high BMI. The specific types of barriers that were strongly perceived varied with the sociodemographic attributes of the participants.ConclusionsThe results show that the perception of barriers to exercise varies among specific population groups, which indicates the importance of targeting exercise promotion strategies to specific populations.

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The physiological roles of isoprene, which is one of the many endogenous volatile organic compounds contained in exhaled breath, are not well understood. In recent years, exhaled isoprene has been associated with the skeletal muscle. Some studies have suggested that the skeletal muscle produces and/or stores some of the isoprene. However, the evidence supporting this association remains sparse and inconclusive. Furthermore, aging may affect breath isoprene response because of changes in the skeletal muscle quantity and quality. Therefore, we investigated the association between the breath isoprene excretion ( V ˙ i s o p r e n e ) and skeletal muscle mass in young (n = 7) and old (n = 7) adults. The participants performed an 18 min cycling exercise after a 3 min rest. The workload corresponded to an intensity of 30% of the heart rate reserve, as calculated by the Karvonen formula. The exhaled breath of each participant was collected during the exercise test. We calculated V ˙ i s o p r e n e from the product minute ventilation and isoprene concentration and, then, investigated the relationships between V ˙ i s o p r e n e and muscle mass, which was measured by multi-frequency bioelectrical impedance analysis. Importantly, muscle mass persisted as a significant determinant that explained the variance in V ˙ i s o p r e n e at rest even after adjusting for age. Furthermore, the muscle mass was a significant determinative factor for V ˙ i s o p r e n e response during exercise, regardless of age. These data indicated that skeletal muscle mass could be one of the determinative factors for V ˙ i s o p r e n e during rest and response to exercise. Thus, we suggest that the skeletal muscle may play an important role in generating and/or storing some of the endogenous isoprene. This new knowledge will help to better understand the physiological functions of isoprene in humans (Approval No. 20190079).