Both westernization of diet and lifestyle habits and chronic inactivity have accelerated the obese population in Japan. Obesity is defined as being a condition in which the excessive energy is stored in the body as fat. Irrespective of organs and tissues, excessive fat accumulation impairs their structure and function, that is, ectopic adiposis. These days, the rapid increase in the number of adult people with abnormal liver function associated with obesity is largely attributed to an increase in the incidence of non-alcoholic fatty liver disease (NAFLD), a chronic liver disease accompanying fat accumulation. In Japan, about 30% of obese people suffer from NAFLD. About 10% of NAFLD progresses to non-alcoholic steatohepatitis (NASH). NASH is a progressive disease leading to liver cirrhosis. Any treatment with consensus other than diet restriction and exercise training is ineffective for the prevention of onset and progression of NAFLD. The important thing is a practice of suitable amounts of exercise, since it maintains muscle volume, increases the utilization of glucose, and attenuates insulin resistance, all of which may contribute to a decease in hepatic fat accumulation levels. It may be of great significance to practice exercise training for patients with chronic liver disease for improving the liver pathophysiology of NAFLD. In this review, first, the onset mechanism for NAFLD in obese subjects is summarized; second, beneficial effects of exercise on liver pathophysiology of NAFLD are reviewed based on the data from a weight reduction program consisting of dietary restriction plus aerobic exercise; and finally, medical support of obese patients with NAFLD in Tsukuba University Hospital are introduced.
To evaluate the association of serum BDNF concentration with high-intensity interval training, 12 healthy male volunteers, aged 28-48 years, completed 16-week high-intensity interval training (HIIT) using ergometer. Training program consisted of >90% VO2 peak for 60 sec separated by 60 sec active rest period for 8-12 sets twice weekly for 16-week. Maximal exercise tolerance tests were performed before (0-week), 4-week, and 16-week after the intervention program. VO2 peak as well as peak watt was linearly increased after 4-week (9% for both VO2 peak and peak watt) and 16-week HIIT training (15% for VO2 peak and 18% for peak watt, p<0.01). However, there was no change in serum BDNF concentration by HIIT. On the other hand, there was a positive association of serum BDNF concentration at baseline with % increase in peak watt after the intervention (ρ=0.60, p<0.05). The association between BDNF and exercise training is still unclear, and more studies are needed to clarify the above positive association.
This study was a nonrandomized controlled trial, aimed to identify the effects of a walking program designed to improve the physical functions of elderly people requiring support or low-level care and receiving rehabilitation services at day care centers. Participants were 28 elderly people (mean age: 77.9±7.5 years). Twelve participants agreed to wear a physical activity monitoring device. Their daily walking goals were updated every week. Sixteen subjects designated as a control group only underwent personalized rehabilitation programs. The gait functions of all subjects were evaluated by several gait parameters before and after the 4-week intervention. ADL and QOL were assessed using the Tokyo Metropolitan Institute Gerontology Index of Competence and 8-Item Short-Form Health Survey (SF-8), respectively. The step length, walking angle, the stance phase ratio and the double-support phase ratio significantly improved in the intervention group after the walking program. Interaction effects of the stance phase ratio, the double-support phase ratio and QOL (mental component summery) were observed between the two groups. The walking program, combined with rehabilitation services, showed favorable effects on the gait functions, and QOL of elderly people, suggesting that it may be useful for preventing functional deterioration of the elderly requiring support or low-level care.
Although the physical activity reference value for older adults (10 METs*hour/week) has been promoted by Japan Ministry of Health, Welfare, and Labour since 2013, little is known about how many steps/day cut-off values that optimally identify meeting the reference value according to the differences of age, sex, medical history, and joint pain. The purpose of this study were 1) to determine the steps/day that optimally identify meeting the reference value, and 2) to identify the differences by the effects of age, sex, medical history, and joint pain on cut-off values. This study included 583 community-dwelling older Japanese adults (aged 73.2 ± 5.4 years; 153 men, 430 women). A uniaxial accelerometer survey was conducted to estimate the total physical activity volume and steps/day. Receiver operating characteristic (ROC) analyses were used to detect steps/day cut-off values for meeting the reference value among all participants and stratified by age, sex, medical history, and joint pain. The optimal cut-off value (AUC (area under the ROC curve), sensitivity, and specificity) for the reference value was 4376 steps/day (0.99, 95.2%, and 97.2%) in all participants. Differences among the cut-off values according to age, sex, medical history, and joint pain ranged from 39 to 169 steps/day. These results suggest that step counts has satisfactory validity to represent the reference value in older adults, and the effects of age, sex, medical history, and joint pain on cut-off values were considerably small. Therefore, this step-count level may be a useful indicator for modifying the daily-life activities of older adults.
Visceral fat accumulation is a notable risk factor in the incidence of lifestyle-related diseases such as metabolic and circulatory disorders. In this study, we measured visceral fat area (VFA) and subcutaneous fat area (SFA) in rugby football players by using dual bioelectrical impedance analysis, as well as other metabolic and circulatory parameters. A total of 28 male players (15 forwards, 13 backs; mean age±SD: 23±4 years) participated in this study. VFA and SFA were significantly correlated with body weight. Thus, heavier players had higher VFA and SFA as well as higher body weight. In addition, VFA was significantly correlated with various blood parameters such as alanine aminotransferase, gamma-glutamyl transpeptidase, and triglyceride. Six of the 28 players met the criteria for visceral obesity, defined as both body mass index ≥25 kg/m2 and VFA ≥100 cm2. In some of these players, blood parameters such as high-density lipoprotein cholesterol <40 mg/dL, triglyceride ≥150 mg/dL, or systolic blood pressure ≥130 mmHg indicated elevated risk for metabolic syndrome. These findings suggest that in athletes like heavier rugby football players, abdominal visceral fat accumulation may indicate risk of lifestyle-related diseases.
Hisashi Kawai, Satoshi Seino, Mariko Nishi, Yu Taniguchi, Shuichi Obuchi, Shoji Shinkai, Hideyo Yoshida, Yoshinori Fujiwara, Hirohiko Hirano, Hun Kyung Kim, Tatsuro Ishizaki, Ryutaro Takahashi, on behalf of the TMIG-LISA Research Group
Physical performance measures, such as gait speed, one-legged stance and hand-grip strength, are known as assessment measures of motor function and predictors for adverse health outcomes, and widely used for assessing motor function in preventive programs for long-term care or screening of frail elderly. However, there is no standard assessment sheet for feedback of the results. In the present study, an assessment sheet on physical performance measures for community-dwelling older adults was developed. A pooled analysis of data from six cohort studies, including urban and rural areas was conducted as part of the Tokyo Metropolitan Institute of Gerontology Longitudinal Interdisciplinary Study on Aging. The pooled analysis included cross-sectional data from 4683 nondisabled, community-dwelling adults aged 65 years or older. Quintiles were derived according to age and sex group for six physical performance measures, i.e., hand-grip strength, one-legged stance, and gait speed and step length at both usual and maximum paces. The assessment sheets, which indicated the physical performance level according to age and sex, were developed by fitting third order polynomial curves to the data. The reference values in the present assessment sheet were considered to be derived from better represented community-dwelling older adults by using more large-scale population-based cohort data than that in the previous study. The assessment sheet should be useful for feeding back results on physical performance measures to elderly individuals and help them better understand their own physical performance levels.