Robustness of the self-referential process under normobaric hypoxia: an fNIRS study using the GLM and homologous cortical functional connectivity analyses.

Introduction: Hypoxia has been reported to impair psychological functions, such as working memory and decision-making. However, few studies have examined hypoxia's effect on social cognition. Methods: Using a self-referential task, the present study investigated normobaric hypoxia's effect on the self-referential process. Additionally, we measured brain activity during the task with fNIRS and performed conventional univariate analysis with the general linear model (GLM) as well as homologous cortical functional connectivity analysis. Results: The results revealed that normobaric hypoxia impaired recognition of adjectives in the other-reference condition but not in the self-reference. The GLM analysis did not detect differences in brain activity between the self- and other-reference conditions, suggesting that GLM analysis may not be suitable for examining self- and other-reference conditions' neural correlates. The homologous cortical connectivity analysis revealed that the connectivity's magnitude was greater in the self-reference than in the other-reference conditions in the normoxic group. However, such a decrease in connectivity in the other-reference conditions was not observed in the hypoxic group, possibly to compensate for cognitive decline induced by the hypoxia. Conclusion: Considering that homologous connectivity reflects the default mode network, which is supposedly linked to continuous self-reference, stable strength of the connectivity in the self-reference condition under the hypoxia may suggest robust nature of the self-reference process under normobaric hypoxia.

Weight-loss-independent benefits of exercise on liver steatosis and stiffness in Japanese men with NAFLD.

BACKGROUND & AIMS: A weight-loss-independent beneficial effect of exercise on non-alcoholic fatty liver disease (NAFLD) management has been reported, but the underlying mechanism is unknown. To help determine this mechanism, the effects of exercise on individual tissues (liver, adipose tissue, and skeletal muscle) were retrospectively studied. METHODS: Data from Japanese obese men with NAFLD in a 3-month exercise regimen were analysed and compared with those in a 3-month dietary restriction program designed to achieve weight loss. The underlying mechanism was studied in a smaller subcohort. RESULTS: Independent of the effect of weight loss, the exercise regimen reduced liver steatosis by 9.5% and liver stiffness by 6.8% per 1% weight loss, and resulted in a 16.4% reduction in FibroScan-AST score. Improvements in these hepatic parameters were closely associated with anthropometric changes (reduction in adipose tissue and preservation of muscle mass), increases in muscle strength (+11.6%), reductions in inflammation and oxidative stress (ferritin: -22.3% and thiobarbituric acid: -12.3%), and changes in organokine concentrations (selenoprotein-P: -11.2%, follistatin: +17.1%, adiponectin: +8.9%, and myostatin: -21.6%) during the exercise regimen. Moreover, the expression of target genes of the transcription factor Nrf2, an oxidative stress sensor, was higher in monocytes, suggesting that Nrf2 is activated. Large amounts of high-intensity exercise were effective at further reducing liver steatosis and potentiating improvements in pathophysiological parameters (liver enzyme activities and organokine profiles). CONCLUSIONS: The weight-loss-independent benefits of exercise include anti-steatotic and anti-stiffness effects in the livers of patients with NAFLD. These benefits seem to be acquired through the modification of inter-organ crosstalk, which is characterised by improvements in organokine imbalance and reductions in inflammation and oxidative stress. LAY SUMMARY: We investigated the effects of exercise on non-alcoholic fatty liver disease (NAFLD) that were not related to weight loss. We found that exercise had considerable weight-loss-independent benefits for the liver through a number of mechanisms. This suggests that exercise is important for NAFLD patients, regardless of whether they lose weight.

A Novel Exercise for Enhancing Visuospatial Ability in Older Adults with Frailty: Development, Feasibility, and Effectiveness.

We aimed to develop a novel exercise to improve visuospatial ability and evaluate its feasibility and effectiveness in older adults with frailty. A non-randomized preliminary trial was conducted between June 2014 and March 2015. We recruited 35 adults with frailty (24 women), aged 66-92 years. Participants were assigned to either locomotive- or visuospatial-exercise groups. All participants exercised under the supervision of physiotherapists for 90 min/week for 12 weeks. The visuospatial exercise participants used cubes with six colored patterns and were instructed to "reproduce the same colored pattern as shown in the photo", using the cubes. In the locomotive exercise group, lower extremity functional training was provided. Rates of retention and attendance measured feasibility. Most participants completed the intervention (77.3%, locomotive; 84.6%, visuospatial) and had good attendance (83.8%, locomotive; 90.7%, visuospatial). Mini-mental state examination (MMSE), clock drawing test (CDT), and seven physical performance tests were conducted before and after interventions. The improvement in the MMSE score, qualitative analysis of CDT, grip strength, and sit and reach assessments were significantly greater in the visuospatial exercise group than in the locomotive exercise group. The cube exercise might be a feasible exercise program to potentially improve visuospatial ability and global cognition in older adults with frailty.

A Single Motivational Lecture Can Promote Modest Weight Loss: A Randomized Controlled Trial.

BACKGROUND: Obesity is a public health problem worldwide. To widely disseminate weight-loss interventions across the target population, a cost-effective approach is needed. OBJECTIVE: We aimed to test whether a single motivational lecture could promote weight loss. METHODS: Our study was a 3-month randomized controlled trial, and we recruited participants via local newspaper advertisements in 3 cities in Ibaraki Prefecture, Japan, and randomly assigned them to a control group (no intervention) and an intervention group, who attended a single motivational lecture lasting approximately 2 h. No other lectures or textbooks were provided. The eligibility criteria included an age of 40-64 years, a body mass index (BMI) of 25-40 kg/m2, and the presence of at least 1 component of metabolic syndrome. The primary outcome was body weight change at 3 months. RESULTS: We enrolled 145 eligible participants with a mean age of 53.8 ± 7.1 years and a BMI of 28.5 ± 3.1 kg/m2. The 3-month body weight change in the control and intervention groups was -0.65 kg (95% confidence interval [CI] -1.09 to -0.20) and -2.48 kg (95% CI -3.01 to -1.95), respectively. The between-group difference was 1.83 kg (95% CI 1.15-2.51). CONCLUSIONS: The significant difference suggested that a single motivational lecture is an effective option to promote modest weight loss in the short term.

Regular aerobic exercise improves sexual function assessed by the Aging Males' Symptoms questionnaire in adult men.

The leading cause of aging-induced male-specific disorders such as physical, mental and/or sexual symptoms is testosterone deficiency. Although aerobic exercise is suggested to improves circulating testosterone levels, physical fitness, depressive symptoms, and sexual function, the effect of regular aerobic exercise on aging-induced disorders has not yet been clarified. Here we performed cross-sectional and interventional studies to identify the effect of aerobic exercise on aging-induced disorders assessed by the Aging Males' Symptoms questionnaire (AMS). In study 1, the relationship between aerobic exercise capacity (i.e. peak oxygen consumption) and AMS scores were cross-sectionally examined in 169 adult men. In study 2, the effect of a 12-week regular aerobic exercise on AMS scores was longitudinally investigated in 18 adult men. In study 1, the AMS-total, AMS-somatic, AMS-psychological, and AMS-sexual scores were significantly correlated to aerobic exercise capacity even after considering age and testosterone levels. In study 2, 12-week aerobic exercise training significantly improved AMS-sexual and tended to improve AMS-total scores. Additionally, an increase in vigorous physical activity was correlated to improve in the AMS-sexual score. These results suggest that regular aerobic exercise is an effective strategy to improve aging-induced disorders in men.

Web-based intervention to promote weight-loss maintenance using an activity monitor: A randomized controlled trial.

The present study examined whether a web-based intervention could promote weight-loss maintenance, after weight loss. The study was a two-phase, 27-month, randomized controlled trial conducted in Ibaraki, Japan, from 2014 to 2017; 133 participants were recruited through local newspaper advertisements. The eligibility criteria were as follows: age of 40-64 years, body mass index of 25-40 kg/m2, and having at least one metabolic syndrome component. In phase 1, a 3-month, group-based weight-loss program was provided to all eligible participants (n = 119). We then randomly assigned (1:1) participants who had lost 5% or more of their weight during phase 1 (n = 95) to either the self-help (mean 3-month weight loss 7.30 kg) or the web-support group (7.00 kg). Participants in the web-support group regularly reported their body weight and physical activity through a web-based system. They received monthly personalized feedback from a study staff for 24 months. The primary outcome, 27-month body-weight change (mean ±â€¯standard deviation), in the self-help and web-support groups were - 5.3 ±â€¯5.0 kg and -4.5 ±â€¯4.9 kg, respectively. There was no significant difference. An exploratory secondary analysis demonstrated that those with greater 27-month increases in their step count, assessed with an accelerometer, lost more weight with no difference in changes in energy intake. The mean 27-month body-weight change in the 4th quartile of changes in step count was -7.78 kg. Although web-based intervention using an activity monitor failed to promote weight-loss maintenance, increased physical activity was associated with successful weight-loss maintenance.

Aerobic exercise training normalizes central blood pressure regulation after oral glucose loading in overweight/obese men.

Central systolic blood pressure (cSBP) decreases after a meal or glucose challenge, but this response is impaired in obesity-related disorders. We investigated whether aerobic exercise training improves cSBP regulation during an oral glucose tolerance test (OGTT) in overweight/obese men. Thirteen overweight/obese men and six normal-weight men (as an alternative comparison instead of a no-exercise group) completed a 12-week aerobic exercise training program. Before and after the program, cSBP (i.e., radial second systolic pressure) was measured using an applanation tonometry at fasting and both 60 min and 120 min after 75 g glucose loading. Before and during the program, physical activity (PA) time was recorded using a tri-axial accelerometer. Pre-training, cSBP was significantly decreased with glucose loading in normal-weight men, while cSBP did not change in overweight/obese men. Post-training, a significant decrease in cSBP was observed in both groups following glucose loading. In addition, the increase in vigorous PA time during the exercise program was significantly correlated to the increase in area above the curve for cSBP during OGTT (demonstrating an improvement in the cSBP response to glucose loading) after the exercise program. These findings may provide novel insights into the role of PA in reducing the cardiovascular risk in obesity.

Association of Foot Structure with the Strength of Muscles that Move the Ankle and Physical Performance.

The human foot plays an important role in supporting body weight, maintaining postural balance, and absorbing ground reaction forces. Although many studies have indicated that a causal relationship exists between foot structure and alterations in lower extremity kinematics, there is little evidence regarding the possible association of foot structure with strength of muscles that move the ankle and physical performance. A total of 67 adult men with a mean age of 51.19 ± 8.82 years participated in this study. Foot structural parameters were assessed using a 3-dimensional foot scanner. Strength of muscles that move the ankle was measured with a dynamometer. Physical performance items, including agility, force, and proprioception, were also measured. We found that all the measured parameters of the length, width, girth, and height of the foot were positively correlated with the strength of plantarflexion, dorsiflexion, eversion, and inversion (r ranged from 0.26 to 0.57; p < .05). Moreover, all or part of the parameters of the length, width, and girth of the foot but not the height and angles of the foot were correlated significantly with vertical jump, stepping forward and backward, and stepping side to side (r ranged from 0.25 to 0.44; p < .05). These findings indicate a weak-to-moderate association between foot structure and the strength of muscles that move the ankle, as well as physical performance. We therefore suggest that a larger foot may have greater muscle strength of the ankle joint and better physical performance.

Mild-to-Moderate Hallux Valgus Does Not Decrease Ankle Muscle Strength in Middle-Aged Japanese Women: A Comparative Study.

Extreme hallux valgus has been documented to be related to lower functional ability and health-related quality of life. It also has a negative effect on foot structure and biomechanical characteristics, which in turn may affect muscle strength in the foot and ankle. Thus, the purposes of this study were to determine whether there is a difference of ankle muscle strength in varied hallux valgus deformities and to investigate correlations between hallux valgus angles and ankle muscle strength. Hallux valgus angles and ankle muscle strength data were collected from 31 middle-aged Japanese women. The hallux valgus angle was measured with a 3-dimensional foot scanner; ankle muscle strength was measured with a dynamometer. Results showed no differences in ankle muscle strength between normal and mild-to-moderate hallux valgus at both 60º/second and 120º/second (p > .05). Unexpectedly, women with mild-to-moderate hallux valgus had a greater value for inversion peak torque per body weight and eversion-to-inversion ratio than those with normal hallux valgus (p = .019 and p = .022) at 120º/second. Furthermore, hallux valgus was correlated with inversion peak torque and peak torque per body weight (r = 0.47; p = .012 and r = 0.50; p = .007) and associated with eversion-to-inversion strength ratio (r = -0.47; p = .012). The findings indicated that mild-to-moderate hallux valgus did not result in a decrease in ankle muscle strength. Conversely, mild-to-moderate hallux valgus had greater ankle inversion strength in middle-aged Japanese women. Further studies are needed to investigate ankle muscle strength in severe hallux valgus deformities.

Increasing Physical Activity Might Be More Effective to Improve Foot Structure and Function Than Weight Reduction in Obese Adults.

Obesity is reported to be an important factor affecting foot structure and function. For obese individuals, weight reduction or increasing weight physical activity could be an effective approach to improve foot structure and function. The present study sought to determine the effect of weight reduction and increasing physical activity on foot structure and function in obese Japanese and to investigate which intervention is more beneficial. The participants were divided into the weight reduction group (n = 30; body mass index 29.0 ± 2.5 kg/m2), with the intervention consisting of dietary modification, and the increasing physical activity group (n = 15; body mass index 28.2 ± 3.1 kg/m2), with the intervention consisting of walking and jogging. A 3-dimensional foot scanner was used to measure the foot anthropometric data with the participants both sitting and standing. The dorsum height declined and the arch stiffness index increased after the weight reduction intervention, and the truncated foot length decreased and the arch stiffness index increased after the increasing physical activity intervention (p <.05). The arch height index showed a downward trend after the weight reduction intervention (p = .060) and an upward trend after the increasing physical activity intervention (p = .069). Moreover, a greater change was found in the increase of the dorsum height and arch height index and decrease of the truncated foot length in the increasing physical activity group than in the weight reduction group (p <.05). These findings suggest that increasing physical activity might be more effective to improve foot structure and function than weight reduction in obese adults.

Relationships between serum free fatty acid and pulse pressure amplification in overweight/obese men: insights from exercise training and dietary modification.

Pulse pressure amplification (i.e., the ratio of peripheral to central pulse pressure) is a strong predictor of cardiovascular events. Circulating free fatty acid, which is a major cause of insulin resistance, has been reported to favorably be associated with pulse pressure amplification in the arm (from the aorta to brachial artery). We hypothesized that this paradoxical relationship depended on an evaluating site of pulse pressure amplification and investigated whether serum free fatty acid level is related to pulse pressure amplification in the arm or trunk (from the aorta to femoral artery) in overweight/obese men. In a cross-sectional study, 85 men participated, and regression analyses revealed that serum free fatty acid level was significantly and independently associated with pulse pressure amplification in the arm but not the trunk. In a longitudinal study, 33 men completed a 12-week lifestyle intervention that involved both exercise training and dietary modification. The lifestyle intervention-induced change in serum free fatty acid level was significantly correlated to that in pulse pressure amplification in the arm but not the trunk. These results support our hypothesis and suggest that pulse pressure amplification should be measured in the trunk instead of the arm in overweight/obese men to simplify its interpretation.

Sexual Function Is an Indicator of Central Arterial Stiffness and Arterial Stiffness Gradient in Japanese Adult Men.

BACKGROUND: As arterial stiffness increases in the absence of subjective symptoms, a personal indicator that reflects increased risk of cardiovascular disease is necessary. Penile erection is regulated by vascular function, and atherosclerosis affects the penile artery earlier than it affects the coronary and carotid arteries. Therefore, we hypothesized that deterioration of erectile function could be a marker of increased risk for cardiovascular disease. To test our hypothesis, we assessed erectile function and arterial stiffness in a cross-sectional study. METHODS AND RESULTS: Carotid-femoral pulse wave velocity (PWV), brachial-ankle PWV, femoral-ankle PWV, and arterial stiffness gradient (PWV ratio: carotid-femoral PWV/femoral-ankle PWV) were measured as indexes of central, systemic, and peripheral arterial stiffness and peripheral organ damage, respectively, in 317 adult men. In addition, erectile function was assessed by using the questionnaire International Index of Erectile Function 5 (a descending score indicates worsening of erectile function). The scores of male sexual function were inversely correlated with carotid-femoral PWV (rs=-0.41), brachial-ankle PWV (rs=-0.35), femoral-ankle PWV (rs=-0.19), and PWV ratio (rs=-0.33). Furthermore, multivariate linear regression analyses revealed that International Index of Erectile Function 5 scores were significantly associated with carotid-femoral PWV (ß=-0.22) and PWV ratio (ß=-0.25), but not with brachial-ankle PWV and femoral-ankle PWV. CONCLUSIONS: Our results indicated that erectile function is independently associated with central arterial stiffness and peripheral organ damage. These findings suggest that male sexual function could be an easily identifiable and independent marker of increased central arterial stiffness and peripheral organ damage.

Randomized trial of amino acid mixture combined with physical activity promotion for abdominal fat reduction in overweight adults.

PURPOSE: The purpose of this study was to test the efficacy of arginine, alanine, and phenylalanine mixture (A-mix) ingestion at 1,500 mg/day in combination with the promotion of physical activity for abdominal fat reduction in overweight adults. METHODS: A placebo-controlled, double-blind, parallel-group, randomized trial for 12 weeks combined with a 4-week follow-up period was conducted at a single center in Minato-ku, Tokyo, Japan, between December 2016 and May 2017. Data were analyzed between June and August 2017. The study participants were 200 overweight adults within the age range of 20-64 years. The participants were randomly assigned to the A-mix group (n=100) or a placebo group (n=100) and were administered 500 mL of test beverage containing 1,500 or 0 mg of A-mix, respectively, for 12 weeks. All participants maintained a physically active lifestyle between week 0 and week 12 through monthly sessions of physical activity. The primary outcomes were the 12-week changes in the abdominal total, subcutaneous, and visceral fat areas, as assessed by computed tomography. RESULTS: Of the 200 enrolled participants, 199 (99%) accomplished the 12-week intervention and 4-week follow-up period. The per-protocol-based analysis for 194 participants demonstrated that the abdominal total fat area decreased significantly in the A-mix group compared with that in the placebo group (difference, 10.0 cm2; 95% confidence interval [CI]: 0.4-19.6 cm2; P=0.041). Comparable outcomes were obtained for the abdominal subcutaneous fat area (difference, 7.4 cm2; 95% CI: 0.1-14.7 cm2; P=0.047). No study-related unfavorable events occurred. CONCLUSION: A-mix supplementation in combination with physical activity promotion facilitated abdominal fat reduction in overweight adults.

Exercise habituation is effective for improvement of periodontal disease status: a prospective intervention study.

BACKGROUND AND PURPOSE: Periodontal disease is closely related to lifestyle-related diseases and obesity. It is widely known that moderate exercise habits lead to improvement in lifestyle-related diseases and obesity. However, little research has been undertaken into how exercise habits affect periodontal disease. The purpose of this study was to examine the effect of exercise habits on periodontal diseases and metabolic pathology. METHODS: We conducted a prospective intervention research for 12 weeks. The subjects were 71 obese men who participated in an exercise and/or dietary intervention program. Fifty subjects were assigned to exercise interventions (exercise intervention group) and 21 subjects were assigned to dietary interventions (dietary intervention group). This research was conducted before and after each intervention program. RESULTS: In the exercise intervention group, the number of teeth with a probing pocket depth (PPD) ≥4 mm significantly decreased from 14.4% to 5.6% (P<0.001), and the number of teeth with bleeding on probing (BOP) significantly decreased from 39.8% to 14.4% (P<0.001). The copy counts of Tannerella forsythia and Treponema denticola decreased significantly (P=0.001). A positive correlation was found between the change in the copy count of T. denticola and the number of teeth with PPD ≥4 mm (P=0.003) and the number of teeth with BOP (P=0.010). A positive correlation was also found between the change in the copy count of T. denticola and body weight (P=0.008), low-density lipoprotein cholesterol (P=0.049), and fasting insulin (P=0.041). However, in the dietary intervention group the copy count of T. denticola decreased significantly (P=0.007) and there was no correlation between the number of periodontal disease-causing bacteria and PPD and BOP. CONCLUSION: Our results are the first to show that exercise might contribute to improvements in periodontal disease.

Vigorous Physical Activity is Associated with Regular Aerobic Exercise-Induced Increased Serum Testosterone Levels in Overweight/Obese Men.

Testosterone is a male sex hormone and low circulating testosterone levels are associated with various health disorders in men. Obesity results in reduced circulating testosterone levels in men. Previously, we demonstrated that lifestyle modifications (combination of aerobic exercise and dietary modification) increase circulating testosterone levels in overweight/obese men. However, the effect of regular aerobic exercise on serum testosterone levels remains unclear. The purpose of this study was to investigate the effect of a 12-week aerobic exercise intervention on circulating testosterone levels in normal-weight and overweight/obese men. Sixteen normal-weight men and twenty-eight overweight/obese men completed a 12-week aerobic exercise intervention. Before and after the intervention, we measured serum total testosterone, free testosterone, and bioavailable testosterone levels, and categorized the physical activity levels (light, moderate, or vigorous) in all participants. At baseline, serum total testosterone, free testosterone, and bioavailable testosterone levels were significantly lower in overweight/obese men than in normal-weight men (all p<0.01). After the 12-week aerobic exercise intervention, serum total testosterone, free testosterone, and bioavailable testosterone levels significantly increased in overweight/obese men (p<0.01). In addition, stepwise multivariable linear regression analysis revealed the increase in vigorous physical activity was independently associated with increased serum total testosterone levels (ß=0.47, p=0.011). We demonstrated that a 12-week aerobic exercise intervention increased serum total testosterone, free testosterone, and bioavailable testosterone levels in overweight/obese men. We suggest that an increase in vigorous physical activity increased circulating testosterone levels in overweight/obese men.

Does Weight Reduction Affect Foot Structure and the Strength of the Muscles That Move the Ankle in Obese Japanese Adults?

Obesity is considered a major influential factor of foot structure and function. It has been reported to result in detrimental alterations of foot structure indicators and a decrease in muscle strength, which can lower the quality of life and increase the morbidity of obesity. The purpose of the present study was to determine the effect of weight reduction on foot structure and the strength of the muscles that move the ankle in obese adults. A total of 33 obese Japanese participants (mean body mass index 28.49 ± 2.87 kg/m2) without an exercise habit participated in a 12-week dietary modification program. Their foot structure indicators were measured using a 3-dimensional foot scanner, and the strength of the muscles that move the ankle was assessed using a dynamometer. After the dietary modification, the mean body weight reduction was 7.49 ± 4.10 kg (9.38%; 77.82 ± 13.26 kg before and 70.33 ± 11.37 kg after; p <.001). The wide foot indicators, including the forefoot girth, rearfoot width, and instep girth, had decreased significantly (p <.05), and the decreases correlated positively with the weight reduction. Regarding the strength of the muscles that move the ankle, except for dorsiflexion, all the measured peak torque values per body weight had increased significantly (p <.01). These results suggest that the weight reduction induced by a 12-week dietary modification results in thinner feet and increased strength of the muscles that move the ankle.

Which cytokine is the most related to weight loss-induced decrease in arterial stiffness in overweight and obese men?

Obesity and increased arterial stiffness are risk factors for cardiovascular disease. A well-known characteristic of obesity is the chronic low-grade inflammatory state, and it causes elevation of arterial stiffness. Weight-loss reduces arterial stiffness and inflammatory level in obese individuals. However, it is unclear which inflammatory factor is most related to weight loss-induce decreases in arterial stiffness in overweight and obese men. Thus, the aim of this study was to determine which circulating cytokine level has the most effect on decreasing arterial stiffness after lifestyle modification. Twenty overweight and obese men completed a 12-week period of lifestyle modifications (combination of aerobic exercise training and dietary modification). We measured brachial-ankle pulse wave velocity (baPWV) as an index of arterial stiffness, and circulating cytokine levels using comprehensive analysis. After the 12-week lifestyle modifications, body mass was markedly decreased. Also, baPWV and the levels of several circulating cytokines significantly decreased after the lifestyle modifications. We observed a positive correlation between changes in baPWV and circulating interleukin-6 (IL-6) levels. Furthermore, multiple liner regression analysis revealed that change in baPWV was significantly associated with that in IL-6 levels after consideration of changes in systolic blood pressure and body mass index. These results suggest that for overweight and obese men, a 12-week period of lifestyle modifications-induced a decrease in circulating cytokine levels (especially IL-6 levels), leads to decreased baPWV.

Dose-ranging pilot randomized trial of amino acid mixture combined with physical activity promotion for reducing abdominal fat in overweight adults.

OBJECTIVE: The objective of this study was to determine the effective dose of an amino acid mixture comprising arginine, alanine, and phenylalanine combined with physical activity promotion in reducing abdominal fat among overweight adults. METHODS: A 12-week randomized, double-blind, placebo-controlled, dose-ranging, pilot trial was conducted in Mito, Japan, from January through April 2016, and the data were analyzed from May through November 2016. The study participants were 35 overweight adults, aged 20-64 years, with no regular exercise habit. Participants were randomly assigned to high-dose (3,000 mg/d, n=9), medium-dose (1,500 mg/d, n=9), low-dose (750 mg/d, n=8), or placebo (0 mg/d, n=9) groups, and the test beverage containing the amino acid mixture or placebo was administered for 12 weeks. All participants maintained a physically active lifestyle during the study period through monthly physical activity promotion sessions and smartphone-based self-monitoring with wearable trackers. Primary outcomes were changes in abdominal total, subcutaneous, and visceral fat areas, assessed by computed tomography. RESULTS: Of the 35 enrolled participants, 32 completed the 12-week follow-up visit. The intention-to-treat analysis revealed that the changes in abdominal total fat area were -14.6 cm2 (95% confidence interval [CI], -39.6 cm2 to 10.4 cm2), -25.3 cm2 (95% CI, -71.0 cm2 to 20.3 cm2), -23.2 cm2 (95% CI, -48.0 cm2 to 1.6 cm2), and -12.5 cm2 (95% CI, -29.1 cm2 to 4.0 cm2) in the high-dose, medium-dose, low-dose, and placebo groups, respectively. Similar results were obtained for visceral and subcutaneous fat areas. No study-related adverse events were reported. CONCLUSION: Compared with placebo, a medium or low dose of the amino acid mixture may facilitate abdominal fat reduction among overweight adults. A larger randomized trial with sufficient statistical power should be implemented to validate the effectiveness of this supplement.

Changes in muscle strength after diet-induced weight reduction in adult men with obesity: a prospective study.

BACKGROUND AND OBJECTIVE: The benefits of weight reduction for musculoskeletal disorders are well understood. Steep declines in muscle mass following considerable weight reduction can decrease muscle strength and, consequently, physical performance. However, only a limited number of studies have examined the changes in muscle mass and strength in the context of interventional weight reduction programs. Thus, we investigated the influence of muscle mass decrease caused by diet-induced weight reduction on muscle strength in obese men. METHODS: A total of 24 men with obesity (body mass index [BMI]: 29.2 ± 2.6 kg/m2; age: 52.4 ± 10.0 years) attended a 12-week weight reduction program that implemented dietary restrictions. Each participant underwent assessments of body weight (by a digital scale), body composition (by whole-body dual-energy X-ray absorptiometry [DEXA]), and upper and lower extremity muscle strength (by a hand-held dynamometer and a Biodex System 3 dynamometer, respectively) before and after the program. RESULTS: The program led to significant reductions of 10.5% of weight and 6.1% of lower extremity muscle mass. Similarly, lower extremity muscle strength (measured using a Biodex System 3 dynamometer) was significantly decreased (isometric 60° peak torque decreased by 10% and isokinetic 60°/s peak torque decreased by 9.4%); however, the level of body weight-normalized lower extremity muscle strength did not significantly change (increased by +1.2% and +1.4%). The decrease in muscle strength was related to but did not entirely depend on decrease in muscle mass. Although handgrip strength did not significantly differ (-2.2%), the weight-normalized level of this parameter significantly improved (+9.1%). In addition, decrease in the percentage of whole-body fat mass and increase in the percentage of muscle mass index were observed. CONCLUSION: We recommend performing exercise after diet-induced weight reduction to regain muscle mass and strength and improve body weight-normalized lower extremity muscle strength.

Weight reduction does not induce an undesirable decrease in muscle mass, muscle strength, or physical performance in men with obesity: a pilot study.

PURPOSE: To date, there have been no reports on whether weight reduction causes decreases in muscle mass, muscle strength, or physical performance that could lead to health problems. Thus, in this pilot study, we investigated the appropriateness of the changes in muscle mass, muscle strength and physical performance after weight reduction. METHODS: Obese men who completed a weight reduction program to decrease and maintain a body mass index (BMI) of less than 25 kg/m2 for one year were recruited for the study. One year after the completion of a weight reduction program, the participants' muscle mass, muscle strength, and physical performance were compared with those in a reference group composed of individuals whose BMI was less than 25 kg/m2. Whole-body scanning was performed using dual-energy X-ray absorptiometry to analyze muscle mass. Handgrip strength and knee extensor strength were measured to evaluate arm and leg muscle strength, respectively. For physical performance, a jump test was employed. RESULTS: The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<0.001). CONCLUSION: Weight reduction participants showed an average reduction in body weight of -16.47%. Normalized arm muscle mass and handgrip strength were significantly greater in the weight reduction group than in the reference group; however, no significant differences were detected between the two groups with respect to the other variables. After one year, there were no significant differences between the two groups.