Effects of Changes in Frequency of Going Out during the COVID-19 Pandemic on ikigai (Sense of Purpose in Life) and Mental Health in Middle-Aged and Older Adults in Japan.

To clarify whether changes in frequency of going out due to the COVID-19 pandemic affect ikigai (sense of purpose in life) and mental health in Japanese middle-aged and older adults. In a questionnaire survey mailed to 16,866 adults aged > 40 years in Japan in September 2020, 7,973 responses were received (response rate, 47.3%) in October 2020. Following exclusions, data from 6,978 individuals (50.6% female, mean age 67.8 ± 12.2 years) were available for analysis. Respondents were categorized based on changes in frequency of going out, reflecting changes in social and/or physical activity, during the pandemic compared with before it: the previously active group went out often before but less often during the pandemic; the remained active group continued going out often; and the inactive group continued not going out often. Whether these changes affected the respondents' ikigai and mental health was investigated. The previously active group had a significantly higher proportion of individuals with decreased ikigai during the pandemic than the other groups. Mental health score decreased in all groups during the pandemic, but more so in the previously active group (-3.21), followed by the inactive and then the remained active groups (-1.45 and -1.28, respectively). Previously active individuals showed the greatest decline in ikigai and mental health among the three groups. These findings suggest that continuing to engage in appropriate physical and social activities, including going out, while following appropriate infection control measures, even under restrictions, can help people maintain ikigai and mental health.

Impact of subjective well-being on physical frailty in middle-aged and elderly Japanese with high social isolation.

Social isolation exacerbates physical frailty and is associated with subjective well-being. Even those with high levels of social isolation may have different health statuses depending on the type of isolation and their subjective well-being. However, the effect of subjective well-being on the relationship between social isolation and physical frailty remains unclear. This study examined whether the risk of physical frailty was the same for individuals with social isolation according to high and low subjective well-being. The study participants included 1,953 middle-aged Japanese adults aged 45 years and older. Physical frailty was assessed using a modified version of the Fried phenotype criteria. Probabilistic Latent Semantic Analysis was used to classify participants according to social isolation indicators. Subsequently, we focused on the groups with high social isolation and classified them according to whether their subjective well-being was high or low. Subjective well-being was evaluated using the Shiawase and Ikigai scales, which are concepts used in Japan. Finally, we used survival time analysis to examine the relationship between Shiawase or Ikigai and physical frailty in groups with high social isolation. The participants were classified into four groups based on their social isolation status. The physical frailty rate of the high social isolation class was 37.0%, which was significantly higher than that of the other classes. Survival time analysis revealed that among people with high social isolation, those with high Shiawase and Ikigai had a significantly lower risk of physical frailty than those with low Shiawase and Ikigai. All individuals with high social isolation are not at a high risk of physical frailty. The findings reveal that even those with high level of social isolation may have a lower risk of physical frailty if their subjective well-being is high. These results will contribute to promoting the prevention of frailty in middle-aged and older adults.

Does participation in municipality-initiated incentivized health promotion programs promote physical activity among the physically inactive? Verification in six Japanese municipalities.

Background: Physical activity can prevent lifestyle-related diseases, such as hypertension and diabetes. However, many people in society are physically inactive, especially middle-aged and older adults over 40. Therefore, this study examined the effects of a municipality-led incentivized health promotion program to clarify: (1) whether the average number of steps increased from the preparticipation period to the 18th month following the program; and (2) whether such increases were influenced by financial incentives. Design and methods: This study analyzed gender, age, step, and incentive type data from 5688 middle-aged and elderly participants in an incentivized health promotion program. The incentives were regional gift certificates that could only be used in local areas, national gift certificates, common points that could be used in department and convenience stores nationwide, and donations. The incentives were worth a maximum of 24,000 yen per year. Results: Both the physically active group and the physically inactive group had increased the step count markedly 18 months post-participation; however those participants chosing financial incentives showed significantly higher steps after 18 months than those who opted for non-financial incentives (time: p < 0.05, time × group: p < 0.05). Conclusions: Municipality-led financially incentivized health promotion programs could motivate increases in the average number of steps taken by those physically inactive residents.

A Structural Analysis of the Effects on the Lifestyle and Health Status of Exercise Class Participants Owing to COVID-19 Prevention Measures.

Objectives: In this study, we aimed to clarify and measure the interrelationships among decrease in communication, exercise, and physical and mental health under COVID-19 prevention measures, restricting individuals from going out of the house. Methods: Participants included 540 middle-aged and older adults who are regular exercise class members. The survey was conducted between April 15 and May 10, 2020. For the self- administered questionnaire survey, a municipal employee of City A and an exercise instructor visited the home of each participant to collect the survey data. The survey items were sex, age, limitation of going out, feeling of inactivity, interaction with others, health status, and forgetfulness; a covariance structural analysis was performed to clarify the interrelationship between lifestyle and health status. Results: Restrictions on going out due to the COVID-19 prevention measures were associated with the physical and mental health of middle-aged and older adults who regularly attended exercise classes because they enforced inactivity and decreased the frequency of conversation. Conclusions: Several waves of COVID-19 may arrive in Japan in the future. Therefore, it is necessary to implement measures to prevent secondary health damage and not focus only on infection prevention.

Epicardial adipose tissue is associated with cardiorespiratory fitness and hemodynamics among Japanese individuals of various ages and of both sexes.

Epicardial adipose tissue may affect hemodynamics and cardiorespiratory fitness as it is a metabolically active visceral adipose tissue and a source of inflammatory bioactive substances that can substantially modulate cardiovascular morphology and function. However, the associations between epicardial adipose tissue and hemodynamics and cardiorespiratory fitness remain unclear. This cross-sectional study aimed to examine the association between epicardial adipose tissue volume and hemodynamics, and cardiorespiratory fitness among Japanese individuals of various ages and of both sexes. Epicardial adipose tissue volume was measured in 120 participants (age, 21-85 years) by cardiac magnetic resonance imaging. To evaluate cardiorespiratory fitness, peak oxygen uptake was measured by cardiopulmonary exercise testing. Peak cardiac output and arteriovenous oxygen difference were calculated by impedance cardiography. The epicardial adipose tissue volume was significantly increased in middle-aged and older women. The epicardial adipose tissue volume was significantly and negatively correlated to peak cardiac output and peak oxygen uptake, regardless of age and sex; furthermore, epicardial adipose tissue showed a strong negative correlation with peak heart rate. Epicardial adipose tissue and peak cardiac output were significantly associated (ß = -0.359, 95% confidence interval, -0.119 to -0.049, p < 0.001), even after multivariate adjustment (R2 = 0.778). However, in the multiple regression analysis with peak oxygen uptake as a dependent variable, the epicardial adipose tissue volume was not an independent predictor. These data suggest that increased epicardial adipose tissue volume may be correlated with decreased peak oxygen uptake, which might have mediated the abnormal hemodynamics among Japanese people of various ages and of both sexes. Interventions targeting epicardial adipose tissue could potentially improve hemodynamics and cardiorespiratory fitness.

Daily steps and healthcare costs in Japanese communities.

Physical inactivity is a pandemic that requires intensive, usually costly efforts for risk reduction of related chronic diseases. Nevertheless, it is challenging to determine the effectiveness of physical activity in healthcare cost reduction based on existing literature. Therefore, this study aimed to investigate the impact of physical activity (daily steps) on healthcare costs utilising the data retrieved from a health promotion project (the e-wellness Project, held in three municipalities in Japan). Evaluating the effects of daily steps, measured by pedometers, on healthcare costs by a quasi-experimental approach among participants aged 40-75 years (about 4000 person-years of observation, between 2009 and 2013), we found that a one-step-increase in the annual average daily step reduced outpatient healthcare costs by 16.26 JPY (≒ 0.11 GBD) in the short run. Based on the assumption of a dynamic relationship between the health statuses in multiple years, the long-run effects of daily steps on healthcare costs were estimated at 28.24 JPY (≒ 0.20 GBD). We determined the health benefits of walking in a sample of middle-aged and older Japanese adults by our findings that an increase in step counts reduced healthcare costs.

Epicardial adipose tissue is tightly associated with exercise intolerance in patients with type 2 diabetes mellitus with asymptomatic left ventricular structural and functional abnormalities.

AIMS: This study aimed to elucidate whether the volume of epicardial adipose tissue (EAT) is associated with left ventricular (LV) structural and functional abnormalities and exercise capacity in patients with type 2 diabetes mellitus (T2DM). METHODS: EAT thickness and LV structural and functional abnormality components (e.g., global longitudinal strain, E/e', LV mass index, relative wall thickness) were measured using echocardiography in 176 patients with asymptomatic stage A and B heart failure (SAHF and SBHF, respectively) and 62 healthy controls (HC). Peak oxygen uptake (peakVO2) was measured by using cardiopulmonary exercise testing. RESULTS: Even when matching study participants for age, sex, and body mass index, the EAT was thicker (HCs 5.5 ±â€¯1.2 versus SAHF 6.4 ±â€¯1.0 and SBHF 9.3 ±â€¯1.7 mm) and peakVO2 was lower (HC 24.1 ±â€¯3.3 versus SAHF 19.1 ±â€¯2.0 and SBHF 16.9 ±â€¯3.1 ml/kg/min) in the heart failure (HF) group than in the HC group (p < 0.001). EAT thickness (ß = -0.189, p < 0.001) and peakVO2 were significantly associated, even after adjusting for multivariates (R2 = 0.457). CONCLUSIONS: In T2DM patients with asymptomatic HF, EAT may be associated with LV structural and functional abnormalities and exercise intolerance.

Effects of daily walking on intermuscular adipose tissue accumulation with age: a 5-year follow-up of participants in a lifestyle-based daily walking program.

PURPOSE: Intermuscular adipose tissue (IMAT) accumulates with age. However, there has been no long-term intervention study examining whether daily walking prevents or decreases the age-related IMAT accumulation. The purpose of this study was to determine effects of a long-term lifestyle-based daily walking program on age-related IMAT accumulation after a 5-year follow-up. METHODS: Using a pedometer, daily step count was evaluated for 5 years in 24 middle-aged and elderly male and female participants. Using magnetic resonance imaging, thigh muscle, thigh subcutaneous adipose tissue, IMAT, abdominal subcutaneous adipose tissue, and visceral adipose tissue were examined at baseline and after 5 years. RESULTS: After 5 years, there was no significant increase in IMAT in all participants. In addition, IMAT significantly decreased in participants with a daily step count of > 9000 (4.0 ± 2.1 vs. 3.1 ± 1.6 cm2; p < 0.05). Moreover, changes in IMAT within 5 years correlated with changes in daily step counts, even after adjusting for confounding factors (p < 0.05). CONCLUSIONS: Long-term lifestyle-based daily walking program prevented the age-related IMAT accumulation in middle-aged and elderly adults. Furthermore, increased daily walking correlated with decreased IMAT over 5 years.

Who opts out of a project for health promotion with incentives?: Empirical research on the effect of rewards to motivate persistence.

Objectives　Although providing incentives for a better lifestyle has been of increasing concern, there is insufficient evidence about its effect. Therefore, this research aims to discover new insights by verifying the effect of rewards to motivate persistence in a project for health promotion.Methods　A total of 7,622 participants of an incentivized project for health promotion (Wellness Point Project) were recruited from 6 municipalities in Japan, namely Tohoku, Chubu, Kanto, Kinki, and Chugoku, of which the 4,291 individuals who had the necessary information for estimation were analyzed. Persistence in the project was judged by whether there was information about daily steps and/or participation in some fitness classes every month for one year at most. In addition, we used the reason participants chose certain rewards in order to categorize the characteristic of rewards, and estimated opt-out hazard ratios from the project using survival time analysis. Furthermore, the estimation in the model included individual features such as age, education, status of physical activity before joining the project, lifestyles such as smoking, drinking, and so on.Results　A multivariate analysis reveals that those who had chosen a reward for regional contribution were more likely to opt out than those who had chosen a certain reward because it is close to cash. The opt-out hazard ratio was 1.63 (95% CI: 1.18-2.25) among men and 1.40 (95% CI: 1.08-1.81) among women. In addition, insufficient physical activity, smoking, working for men, and physical condition for women were associated with opt-out.Conclusions　This research verified that a reward that participants felt was close to cash, compared to the internal motivation of regional contribution, could enhance the persistence rate of the project. Moreover, it was found that not only giving incentives but also considering participants' conditions is necessary to enhance persistence.

Effects of a Lifestyle-Based Physical Activity Intervention on Medical Expenditure in Japanese Adults: A Community-Based Retrospective Study.

Background. This study aimed to investigate whether a lifestyle-based physical activity program could contribute to reduced medical expenditure. Methods. The study participants were 60 adults aged 63.1 (standard deviation, 4.4) years in the intervention group; the case-control group consisted of 300 adults who were randomly selected from Japan's national health insurance system. This community-based retrospective study incorporated a 3-year follow-up. Results. The total and outpatient medical expenditure in the intervention group were significantly lower than in the control group: total expenditure, $US640.4/year; outpatient expenditure, $369.1/year. The odds ratio for outpatient visiting was 6.47-fold higher in the control than in the intervention group. Conclusion. Our study suggests that a health program to promote physical activity can result in reduced total medical expenditure, outpatient medical expenditure, and possibly also inpatient medical expenditure.

Relationship between thigh intermuscular adipose tissue accumulation and number of metabolic syndrome risk factors in middle-aged and older Japanese adults.

BACKGROUND: To evaluate the association between thigh intermuscular adipose tissue accumulation and number of metabolic syndrome risk factors in middle-aged and older Japanese adults. METHODS: Thigh muscle cross-sectional area, subcutaneous adipose tissue, thigh intermuscular adipose tissue, abdominal subcutaneous adipose tissue, and visceral adipose tissue were measured in 166 middle-aged and older (mean age, 69years) Japanese adults using magnetic resonance imaging. Daily physical activity was calculated using pedometers, and energy intake per day was evaluated using 3-day dietary records. Multiple linear regression analysis was used to assess the association between intermuscular adipose tissue and the number of metabolic syndrome risk factors. RESULTS: Multiple regression analysis indicated that intermuscular adipose tissue was significantly associated with the number of metabolic syndrome risk factors, after adjusting for age, sex, body mass index, daily physical activity, energy intake, thigh muscle cross-sectional area, and visceral adipose tissue (p<0.05). CONCLUSIONS: Thigh intermuscular adipose tissue accumulation was significantly associated with the number of metabolic syndrome risk factors in middle-aged and older Japanese adults, independent of age, sex, body mass index, daily physical activity, energy intake, thigh muscle cross-sectional area, and visceral adipose tissue.

A common genetic variant of the chromogranin A-derived peptide catestatin is associated with atherogenesis and hypertension in a Japanese population.

Chromogranin A (CHGA) is a major protein in the secretory granules of chromaffin cells. CHGA also gives rise to cardiovascular/metabolism regulatory peptides, such as catestatin (CST) and pancreastatin (PST). While CST is a potent inhibitor of catecholamine secretion, PST is a potent physiological inhibitor of glucose-induced insulin secretion. Recently, several SNPs were identified in the CST and PST domains of CHGA locus in different populations. Among the discovered SNPs, CST variant allele Ser-364 was associated with blood pressure alteration and PST variant allele Ser-297 was associated with significantly higher plasma glucose level. In this study, we examined whether these CST and PST variant alleles exist and influence cardiovascular and metabolic phenotypes in Japanese population. Our study comprised of 343 Japanese subjects aged 45-85 years (143 men and 200 women, mean age 66 ± 8 years). We determined the genotypes of CST and PST by PCR-direct sequencing method and carried out genotype-phenotype association analysis. In 343 participants, the minor allele frequency of CST variant Ser-364 was 6.10%. On the other hand, we did not detect the PST variant Ser-297 in this entire study population. The presence of Ser-364 allele was associated with increased in baPWV (an index of systemic arterial stiffness) that suggests an initiation and/or progression atherogenesis and hypertension. The Ser-364 allele was also associated with elevated systolic blood pressure and pulse pressure, consistent with increased baPWV. In conclusion, the CST Ser-364 allele may increase the risk for cardiovascular diseases in Japanese population.

The effects of Lactobacillus pentosus strain b240 and appropriate physical training on salivary secretory IgA levels in elderly adults with low physical fitness: a randomized, double-blind, placebo-controlled trial.

The purpose of the study was to evaluate the effects of Lactobacillus pentosus strain b240 (b240) intake and appropriate physical training on salivary secretory immunoglobulin A secretion in elderly adults with low physical fitness. Elderly adults with low physical fitness (daily step count below 3,500 steps) were divided into 2 groups: a b240 intake + exercise group (b240 group) and a placebo intake + exercise group (placebo group). Each subject continued intake of b240 or placebo and moderate-intensity resistance exercise for 12 weeks. Before and 4, 8, and 12 weeks after the start of intervention, each subject underwent saliva sampling. Before and after intervention, physical fitness tests and step count were measured. Our results showed that secretory immunoglobulin A secretion in 57 subjects during the b240/placebo intake period was significantly greater in the b240 group than in the placebo group (p<0.05). There were no significant changes in physical fitness tests before and after intervention in the 2 groups. The daily amount of walking increased significantly after intervention in both groups (p<0.05). These results suggest that in elderly adults with low physical activity and fitness, intake of b240 with appropriate physical exercise elevate salivary secretory immunoglobulin A secretion.

Objectively measured light-intensity lifestyle activity and sedentary time are independently associated with metabolic syndrome: a cross-sectional study of Japanese adults.

BACKGROUND: Reducing sedentary time and increasing lifestyle activities, including light-intensity activity, may be an option to help prevent metabolic syndrome (MetS). The purpose of the present study was to examine whether objectively measured light-intensity lifestyle activity and sedentary time is associated with MetS, independent of moderate-vigorous intensity physical activity (MVPA). METHODS: The participants in this cross-sectional study were 483 middle-aged Japanese adults, aged 30-64 years. The participants were divided into those with or without MetS according to the Japanese criteria for MetS. A triaxial accelerometer was used to measure light-intensity lifestyle activity [1.6-2.9 metabolic equivalents (METs)] and sedentary time (≤1.5 METs). Logistic regression was used to predict MetS from the levels of light-intensity lifestyle activity and sedentary time with age, sex, smoking, calorie intake, accelerometer wear time, and MVPA as covariates. RESULTS: The odds ratios (OR) for MetS in the highest and middle tertiles of light-intensity lifestyle activity were 0.44 [95% confidence interval (CI): 0.24 to 0.81] and 0.51 (95% CI: 0.29 to 0.89) relative to the lowest tertile, after adjustment for age, sex, smoking, calorie intake, accelerometer wear time and MVPA (Ptrend = 0.012). Sedentary time was also associated with the risk of MetS (Ptrend = 0.018). Among participants in the highest tertile of sedentary time, the risk of MetS was 2.27-times greater than that in the lowest tertile (95% CI: 1.25 to 4.11). The risk of MetS was not significantly increased in subjects in the middle tertile of sedentary time. CONCLUSIONS: We found that light-intensity lifestyle activity and sedentary time were significantly associated with the risk of MetS, independent of MVPA. The results of our study suggest that public health messages and guidelines should be refined to include increases in light-intensity lifestyle activity and/or decreases in sedentary time, alongside promoting MVPA, to prevent MetS.

Lifestyle-based physical activity intervention for one year improves metabolic syndrome in overweight male employees.

Regular physical activity is associated with improvements of metabolic syndrome (MetS) risk factors. Furthermore, recent physical activity guidelines for health promotion recommend that moderate to vigorous physical activity should be performed in bouts lasting ≥ 10 min. Brisk walking is a popular and readily attainable form of moderate intensity physical activity and is suitable for the majority of individuals. However, it is unclear whether brisk walking lasting ≥ 10 min is associated with improvement in MetS. This study aimed to determine the effects of a 1-year lifestyle-based physical activity intervention with brisk walking of ≥ 10 min using a pedometer on the improvement in MetS. Three hundred and seventy-six overweight male employees with ≥ 1 MetS component(s) participated in this intervention study from 2008 to 2009 (age, 30-62 years; body mass index, 23.0-45.5 kg/m(2)). Overall, 316 participants (84%) completed the 1-year intervention. MetS was defined according to the Japanese criteria at baseline and after 1 year. Brisk walking lasting ≥ 10 min was significantly associated with the decrease in waist circumference (ß = -1.479) and triglyceride (ß = -31.260), and the increase in high-density lipoprotein cholesterol (ß = 2.117). The brisk walking step counts were also significantly associated with higher odds for an improvement in MetS (OR, 1.48; 95% CI, 1.05-2.09) and abdominal obesity (OR, 1.45; 95% CI, 1.12-1.87). In conclusion, the lifestyle-based intervention with brisk walking of ≥ 10 min is an effective strategy to improve MetS in overweight male employees.

Association between physical activity and metabolic syndrome in middle-aged Japanese: a cross-sectional study.

BACKGROUND: Although many studies have reported an association between self-reported physical activity and metabolic syndrome (MetS), there is limited information on the optimal level of physical activity required to prevent MetS. This study aimed to determine the association between objectively measured physical activity and MetS in middle-aged Japanese individuals. We also determined the optimal cutoff value for physical activity required to decrease the risk of developing MetS. METHODS: A total of 179 men and 304 women, aged between 30 and 64 years, participated in this study. Participants were divided into two groups using the Japanese criteria for MetS as those with MetS or pre-MetS, and those without MetS. Participants were considered to be physically active if they achieved a physical activity level of 23 metabolic equivalents (METs) h/week, measured using a triaxial accelerometer. The association between physical activity and MetS was analyzed using logistic regression with the following covariates: sex, age, sedentary time, low intensity activity, calorie intake, smoking, menopause and body mass index. We also evaluated the factors that determined the association between the prevalence of MetS and pre-MetS and the physical activity cutoff value using classification and regression tree (CART) analysis. RESULTS: The odds ratio for MetS and pre-MetS was 2.20 for physically inactive participants (< 23 METs h/week), compared with physically active participants (≥ 23 METs h/week). The corresponding odds ratios for men and women were 2.27 (P < 0.01) and 1.95 (not significant), respectively. CART analyses revealed that moderate-vigorous physical activity of > 26.5 METs h/week was sufficient to decrease the prevalence of MetS and pre-MetS in middle-aged Japanese men and women. CONCLUSIONS: The results of this cross-sectional study indicate that the Exercise and Physical Activity Reference for Health Promotion 2006 is inversely associated with the prevalence of MetS in men. Our results also suggest that moderate physical activity of > 26.5 METs h/week may decrease the risk of developing MetS and pre-MetS in middle-aged Japanese individuals.

Monocyte and T-cell responses to exercise training in elderly subjects.

The purpose of this study was to examine the effects of exercise training on age-related impairment of immune parameters related to T-cell activation in elderly individuals. Twenty-four elderly subjects were assigned to an exercise training group (EXC: 3 men, 9 women; age 61-76 years) or a nonexercise control group (CON: 4 men, 8 women; age 62-79 years). Subjects in EXC participated in exercise sessions 2 d·wk(-1) for 12 weeks. The training session included stretching and endurance exercise (10 minutes), resistance training comprised leg extension, leg press, hip abduction, and hip adduction using exercise machine and each subject's body weight. Subjects in CON maintained their normal physical activity levels during the study period. Blood samples were collected before and after the training period. Samples were measured for the numbers of leukocytes, lymphocytes, and monocytes, and for CD3(+), CD4(+), CD8(+), CD28(+)CD4(+), CD28(+)CD8(+), TRL-4(+)CD14(+), and CD80(+)CD14(+) cells. The number of leukocytes, lymphocytes, monocytes, CD3(+), CD4(+), and CD8(+) cells did not change after 12 weeks in either EXC or CON. The number of CD28(+)CD8(+) cells increased significantly after training in EXC (p ≤ 0.05), although CON showed no significant change. In the EXC group, CD80(+)CD14(+) cell counts were significantly higher after training (p ≤ 0.05), but the TLR-4(+)CD14(+) cell counts were unchanged. In the CON group, no significant alteration existed in TLR-4(+)CD14(+) and CD80(+)CD14(+) cell numbers. In conclusion, exercise training in elderly people is associated with increased CD28-expressing Tc cells and CD80-expressing monocytes. Therefore, exercise training might upregulate monocyte and T-cell-mediated immunity in elderly people.

Age differences in the relation between ACTN3 R577X polymorphism and thigh-muscle cross-sectional area in women.

The relation between ACTN3 R577X polymorphism and muscle mass in women has been reported, but its relation to age remains unclear. We investigated the relationship between ACTN3 R577X polymorphism and muscle mass in both middle-aged and elderly women. Two age groups (middle-aged and older) were formed among 162 healthy, nontraining Japanese women (mean ± SE, 58.6 ± 0.8 year). Their midthigh-muscle cross-sectional area (CSA) was assessed using magnetic resonance imaging, revealing no difference in thigh-muscle CSA among ACTN3 R577X genotypes in the middle-aged group (XX, 87.3 ± 2.5 cm(2); RR&RX, 86.1 ± 1.7 cm(2), p=0.7). In contrast, the XX genotype in the older group had a smaller thigh-muscle CSA adjusted to body weight than the RR&RX genotypes (XX, 67.8 ± 2.0 cm(2); RR&RX, 72.5 ± 1.2 cm(2), p<0.05). The present study showed an association between ACTN3 R577X polymorphism and smaller thigh-muscle CSA in a group of elderly women but not in a group of middle-aged women.

Effect of aerobic leg exercise training on subcutaneous adipose tissue of thigh in young Japanese women.

A one-legged training model was adopted to assess the influence of moderate-intensity exercise training on subcutaneous adipose tissue, especially focusing on the trained limb. Eight young sedentary Japanese women (ages 21-23 yr) participated in a 12-week training program. The leg was assigned randomly to trained or untrained limb. Each subject performed a supervised 60-min one-legged cycle ergometer training session three times a week. The exercise intensity was set at approximately 40% of peak VO(2) ("moderate" intensity, i.e., below the estimated lactate threshold), which was determined before training. Each subject performed a one-legged incremental cycle exercise test until exhaustion to determine the peak VO(2) of each leg (the trained and untrained legs being investigated separately). The areas of subcutaneous fat and the remaining nonfat tissues of the thigh were evaluated by our novel visualized measuring system based on ultrasonography. The fat cross-sectional areas of the trained and untrained thigh were not different after training (trained: 68.6+/-17.8 vs. untrained: 68.3+/-18.5 cm(2)). The non-fat (muscle and bone) area was also similar between the trained and untrained limb. In addition, there was no systematic influence of the training on the total and lean body mass. After training, the duration time of the one-legged cycle incremental exercise test by the trained leg was significantly improved unilaterally (trained: 1049+/-122 vs. untrained: 930+/-109 s, p<0.05) without any difference of peak VO(2). The results indicate that moderate one-legged aerobic training did not induce any compositional change in the trained thigh; rather, what did improve were certain peripheral factor alone relating to endurance.