The modern environment has been explicitly engineered to reduce manual labor, increase physical comfort and afford passive entertainment. As a result, physical inactivity and sedentary pastimes have become ubiquitous features of the post-industrial world. Given the fact that human metabolic, cardiovascular and musculoskeletal systems evolved in an environment in which survival necessitated extraordinary amounts of physical exertion, it is not surprising that physical inactivity has induced a host of morbidities. Epidemiological evidence has demonstrated that inactivity has significant risks and severe consequences for all individuals independent of age, genetic endowment, personal history (e.g., past lifestyle), body composition and current behavior (e.g., diet, alcohol consumption, smoking). Physical inactivity accelerates the aging process and dramatically increases the frequencies of non-communicable diseases (NCDs) such as cardiovascular disease (CVD), type-2 diabetes (T2D) and other pathologies (e.g., frailty, osteoporosis, sarcopenia, and obesity). The relative risks of physical inactivity and mortality from NCDs begin in childhood and increase with advancing age. Nevertheless, physical activity (PA) and exercise have been demonstrated to delay and/or prevent the onset of NCDs and other pathologies associated with sedentary lifestyles and aging. This review surveys data from observational studies and randomized controled trials (RCTs) that support the premise PA and exercise are essential elements in the maintenance of health as well as the prevention and treatment of age-related maladies and NCDs.
Exercise is one of the beneficial ways to reduce or manage weight. However, some studies have reported that actual weight reduction induced by exercise intervention was less than the expected amount. This phenomenon occurred more frequently in women subjects than men subjects. One of reasons for decreased actual weight reduction is energy compensation after exercise which is derived from decreased non-exercise activity thermogenesis (NEAT) and increased food intake. Several investigations reported that, when subjects started an exercise intervention, NEAT gradually decreased over several weeks, although other studies using a doubly labeled water method showed total energy expenditure, including exercise and NEAT components, did not decrease during exercise intervention. However, the magnitude of energy compensation through increased food intake seemed to be greater than that through decreased NEAT. It is reported that women especially showed energy compensation through increased food intake and that a high amount of instructed exercise was also a trigger for higher energy compensation. Furthermore, a medium-term exercise intervention resulted in the improvement of satiety response after meals, which may be related to changes in appetite hormones. However, there is large individual variability in energy compensation response which cannot be fully explained by known factors. Further studies are needed, including an approach from the field of brain science.
Purpose: In 2006, the Ministry of Health, Labour and Welfare published "Exercise and Physical Activity Reference for Health Promotion 2006". This report showed reference values and ranges of the maximal oxygen uptake for health promotion. However, there are no epidemiological studies that have investigated the relationship between these values and ranges in relation to mortality. Therefore, we assessed the existing data of our cohort study among Japanese male workers.
Methods: Subjects were 8,935 Japanese male workers. The median age was 35 years old (IQR: 29 to 43). The maximum oxygen uptake was estimated using a submaximal cycle ergometer test between 1982 and 1988. The men were classified into four groups based on the reference values and ranges, the below the range group (Group I), the bottom of the range to below the reference value group (Group II), the reference value to the upper range group (Group III), and the over the range group (Group IV). We investigated mortality until June 30, 2003. We used the proportional hazards model in order to obtain the relative risks (RR) for mortality across each group. Multivariate RR and 95% confidence intervals (95% CI) for mortality were obtained while adjusting for age, systolic blood pressure, cigarette smoking, and alcohol intake.
Results: There were 360 deaths during the follow-up period. Using Group I as reference, the RR and 95% CI for Group II to Group IV were 0.76 (0.58-0.99), 0.59 (0.43-0.80), and 0.80 (0.49-1.31), respectively (p for trend = 0.009).
Conclusion: These findings suggest that Japanese male workers in the upper range of the reference values of maximal oxygen uptake for health promotion have a lower RR of mortality.
Objective: Physical activity and sedentary behavior in preschool children have been linked to health consequences from early childhood through adulthood. Understanding the correlates of physical activity and sedentary behaviors is an important issue. The associations of family and neighborhood environments with outside play time and screen time on weekdays of preschool children in Japan were examined.
Methods: A cross-sectional study on 2598 pairs of children ages 3-6 years who attended childcare facilities, and their mothers, in a city in the Tohoku region was conducted. The children's physical activity (outside play and screen time per weekday), family environment (living with grandparents, number of siblings, maternal employment, height, and weight), neighborhood environment (safe space to play outside and friends to play with), and child characteristics (age and sex) were surveyed using a self-administered questionnaire. The independent associations between outside play time or screen time and family and neighborhood environment variables were examined using multiple logistic regression analysis adjusted for family and neighborhood environments, and child characteristics.
Results: The eligible participants were 1634 children (mean age: 4.2 years, boys: 52.9%). After controlling for covariates, spending 1 or more hours/day in outside play time, as an indicator of physical activity, was inversely associated with non-living with grandparents (OR (95% CI); 0.76 (0.60-0.97)) and lack of friends to play with (0.36 (0.28-0.45)). These environments were risk factors for lower physical activity. Furthermore, 2 or more hours/day screen time, as an indicator of sedentary behavior, was significantly associated with the presence of a full-time housewife (1.29 (1.02-1.63)), maternal obesity (2.24 (1.50-3.34)), and lack of friends to play with (1.34 (1.09-1.65)).
Conclusion: These results suggest that absence of a child's peers or someone to play with, both within and outside the family, the presence of a full-time housewife, and maternal obesity could be important factors of influence on children's physical activity. Population-based intervention to establish healthy lifestyles, including physical activity in preschool children, should therefore target both family and neighborhood environments.