Yasutomi Katayama

Effects of Aerobic Exercise on Metabolic Syndrome Improvement in Response to Weight Reduction

Objective: The objective was to test effects of aerobic exercise training on metabolic syndrome (MetSyn) improvement in response to weight reduction.

PPARG Genotype Accounts for Part of Individual Variation in Body Weight Reduction in Response to Calorie Restriction

Several studies indicate that expression of the peroxisome proliferator–activated receptor γ (PPARG) gene is influenced by calorie restriction. The aim of this study was to investigate whether PPARG gene variations are associated with weight reduction and changes in coronary heart disease (CHD) risk factors in response to a 14‐week calorie restriction. In total, 95 middle‐aged, Japanese women (BMI ≥25 kg/m2) enrolled as subjects for 14 weeks and attended weekly dietary lectures instructing them on how to consume a nutritionally balanced diet of 1,200 kcal/day. Eight single‐nucleotide polymorphisms (SNPs) in the PPARG gene (rs1801282 (Pro/Ala), rs2292101, rs2959272, rs1386835, rs709158, rs1175540, rs1175544, and rs1797912) were analyzed. Body weight decreased significantly (−7.7 ± 3.1 kg; −11.3 ± 4.4%) during the intervention. Six PPARG SNPs (rs2959272, rs1386835, rs709158, rs1175540, rs1175544, and rs1797912) were significantly associated with the weight reduction, with rs1175544 having the strongest association (P = 0.004). No differences across the rs1175544 genotypes were observed in any of the blood analyses or in blood pressure. In a multiple regression analysis, the rs1175544 genotypes accounted for 7% of the total weight reduction variance. These data suggest that one SNP of the PPARG genotype accounted for a significant portion of the total body weight reduction variance in response to a short‐term intervention consisting of calorie restriction; however, no relationship was found between these SNPs and the changes in CHD risk factors which accompanied weight loss.

Influence of acute aerobic exercise on adiponectin oligomer concentrations in middle-aged abdominally obese men

Exercise intensity may induce changes in total adiponectin and adiponectin oligomer levels. However, the effects of acute aerobic exercise on total adiponectin and adiponectin oligomers in middle-aged abdominally obese men remain unknown. The purpose of this study was to investigate the influence of aerobic exercise intensity on changes in the concentrations of total adiponectin and adiponectin oligomers (high-molecular weight [HMW] and middle- plus low-molecular weight [MLMW] adiponectin), and the endocrine mechanisms involved in exercise-induced changes in adiponectin oligomer profiles in middle-aged abdominally obese men. Using a crossover design, 9 middle-aged abdominally obese men (age, 54.1 ± 2.4 years; body mass index, 27.9 ± 0.6 kg/m²) underwent 2 trials that consisted of 60 minutes of stationary cycle exercise at either moderate-intensity (ME) or high-intensity (HE) aerobic exercise (50% or 70% of peak oxygen uptake, respectively). Blood samples were collected to measure the concentrations of adiponectin oligomers, hormones (catecholamines, insulin, and growth hormone), metabolites (free fatty acid, glycerol, triglyceride, and glucose), and cytokines (interleukin-6 and tumor necrosis factor-α). After exercise, plasma catecholamine concentrations were higher during HE than during ME (P < .05). Total adiponectin concentration decreased at the end of HE (P < .05), but remained unchanged after ME. The HMW adiponectin concentration did not change at either intensity, whereas the MLMW concentration decreased at the end of HE (P < .05). The ratio of HMW to total adiponectin concentration increased significantly (P < .05), whereas the ratio of MLMW to total adiponectin concentration decreased significantly (P < .05), at the end of HE. The percentage changes in epinephrine concentration from baseline to the end of exercise were correlated with the percentage changes in total adiponectin concentration (r = -0.67, P < .05) and MLMW adiponectin concentration (r = -0.82, P < .05) from baseline to the end of HE. Our results indicate that the change in total adiponectin was mainly due to a change in MLMW adiponectin concentration during high-intensity exercise in middle-aged abdominally obese men. Epinephrine may partially regulate the decrease in total and MLMW adiponectin concentrations during high-intensity exercise.

Effects of obesity phenotype on fat metabolism in obese men during endurance exercise

Objective:The effects of obesity phenotype on fat metabolism during endurance exercise are unclear. This study aimed to investigate in obese men whether body fat distribution would influence plasma fat availability and oxidation during endurance exercise.Design:Fourteen sedentary men (body mass index (BMI)>25 kg/m2) were divided into two groups by visceral fat (VF) area: VF obese (VF-Ob) (n=7, age; 52.0±2.5 (s.e.) years) and abdominal subcutaneous fat obese (SF-Ob) (n=7, age; 57.3±2.8 (s.e.) years). All participants performed stationary cycling exercise for 60 min at 50% of peak oxygen uptake.Measurements:Blood and respiratory gas samples were taken for analysis of hormone, metabolite and substrate oxidation in each participant at rest and during exercise.Results:There is a significant group × time interaction in the plasma concentration of free fatty acid (FFA) (P<0.05) and glycerol (P<0.05) during the exercise bout. In addition, total plasma concentration of FFA (area under the curve) was 59.2% higher in VF-Ob compared with SF-Ob men during endurance exercise (1.99±0.24 and 1.25±0.13 mEq/l/min, respectively; P<0.05). Total plasma concentration of glycerol (area under the curve) was 102.3% higher in VF-Ob than SF-Ob men during the exercise (69.6±12.5 and 34.4±5.1 mg/dl/min, respectively; P<0.05). However, fat oxidation was not different throughout the exercise between VF-Ob and SF-Ob men (176.5±25.7 and 183.0±12.8 kcal/60 min, respectively).Conclusion:During moderate endurance exercise, plasma fat availability may be higher in men with VF obesity compared to men with SF obesity. However, total fat oxidation is similar between obesity phenotype.

Weight reduction can decrease circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in overweight middle-aged men.

Circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) has been reported to be associated with acute coronary syndrome, but its association with obesity has not been elucidated. In this study, we examined whether weight reduction would reduce the serum levels of sLOX-1 in a 12-week weight reduction intervention. Thirty-eight overweight middle-aged men were enrolled in the study, and 32 completed the intervention. The serum level of sLOX-1 was measured using a chemiluminescent enzyme-linked immunoassay. After the intervention program, body weight and the serum level of sLOX-1 decreased significantly (-7.5% +/- 4.8% and -72.1% +/- 35.9%, respectively). Changes in serum levels of sLOX-1 were positively correlated with changes in body weight (r = 0.54, P = .003), body mass index (r = 0.57, P = .001), body fat mass (r = 0.57, P = .002), total cholesterol (r = 0.41, P = .03), subcutaneous fat area (r = 0.50, P = .007), high-sensitivity C-reactive protein (r = 0.56, P = .002), leptin (r = 0.47, P = .01), and tumor necrosis factor-alpha (r = 0.32, P = .09); but no correlations were observed with fasting glycemic-related factors (blood glucose, hemoglobin A(1c), and insulin). Changes in body mass index and high-sensitivity C-reactive protein were selected as significant predictors of sLOX-1 changes by multiple regression analyses. These results suggest that LOX-1 induction may be related to adipocyte metabolism, inflammation, and immune response associated with obesity.

Obesity phenotype and intra-abdominal fat responses to regular aerobic exercise

AIM To examine the effects of obesity phenotype on abdominal fat responses to regular aerobic exercise. METHOD Fifty-seven obese men aged 34-70 years were divided into two groups based on baseline intra-abdominal fat (IF) area measured by computerized tomography: moderate (<200 cm(2)) IF (MIF; n=33, age: 52.9+/-10.6 [SD] yr, body mass index [BMI]: 29.2+/-3.1 kg/m(2)) or high (>or=200 cm(2)) IF (HIF; n=24, age: 53.5+/-9.5 yr, BMI: 30.3+/-3.1 kg/m(2)). The 12-week exercise program consisted primarily of aerobic exercise and met 3 days per week for 90 min per session. Weight, BMI, body composition (by dual-energy X-ray absorptiometry), IF and subcutaneous fat (SF) areas were measured before and after the program. RESULTS Regular aerobic exercise reduced weight by 2.3+/-2.2 kg in MIF and 3.2+/-3.0 kg in HIF. HIF reduced significantly more IF area than MIF (15.1+/-26.0 cm(2) in MIF and 43.3+/-41.9 cm(2) in HIF), and the difference remained significant after adjusting for baseline fat mass, weight change and total energy intake during the 12-week aerobic exercise. CONCLUSION Exercise-induced IF reduction may be remarkably influenced by obesity phenotype.

The effects of vigorous physical activity on intra-abdominal fat levels: A preliminary study of middle-aged Japanese men

AIM To examine the effects of vigorous physical activity (PA) on intra-abdominal fat (IF) levels in obese men. METHODS Thirty-seven obese men (mean age: 47.6+/-8.6 years) engaged in a 12-week aerobic exercise program on a regular basis (3 days/week). We divided them into low volume of vigorous PA group (n=19) or high volume of vigorous PA group (n=18), based on the median time spent (34.3min/week) in vigorous PA (over 6.1 metabolic equivalents assessed by a single-axis accelerometer) throughout the program. RESULTS Regular exercise reduced IF levels (measured by computed tomography) from 188.1+/-53.9cm(2) to 170.3+/-46.6cm(2) for the low volume of vigorous PA group and from 167.9+/-44.3cm(2) to 137.9+/-40.6cm(2) for the high volume of vigorous PA group. Two-way (time x group) ANOVA revealed no significant interactions for the IF level. However, correlation analysis for all participants showed that time spent in vigorous PA throughout the program significantly correlated to IF reductions after adjusting for initial levels of IF, vigorous PA and weight changes (r=-0.42, P=0.02). CONCLUSION This study suggests that vigorous PA may affect IF reductions in obese men.

Effects of diet with or without exercise on leptin and anticoagulation proteins levels in obesity.

Obesity is a risk factor for cardiovascular disease and thromboembolic events. We investigated the effects of weight reduction by a 12-week calorie-restricted diet with or without aerobic exercise (diet group and diet plus exercise group) on leptin and anticoagulation proteins levels. Forty-two obese nondiabetic individuals were evaluated for blood levels of leptin, protein C activity, free protein S antigen and for body fat area calculated on computerized tomography before and after intervention. Before intervention, serum levels of leptin and free protein S antigen correlated positively with several adiposity-related parameters. After the program, body weight and fat area were significantly decreased in both groups. Body mass index and leptin levels decreased in both groups, with a larger change in the diet plus exercise group than in the diet group. Although protein C activity levels did not change in both groups, free protein S antigen levels decreased significantly in the diet plus exercise group. In conclusion, the 12-week programs had significant effects on the initial weight reduction and body fat mass, decreasing lepin levels in obese nondiabetic individuals. To clarify whether aerobic exercise has additional or direct effects on the anticoagulation system, a study in a large number of individuals is needed.

Sex differences in substrate oxidation during aerobic exercise in obese men and postmenopausal obese women.

The aim of this study was to compare substrate oxidation during aerobic exercise in obese men and postmenopausal obese women. Ten obese men (mean age, 55.4 +/- 2.2 years; body mass index, 27.5 +/- 0.4 kg/m(2); peak oxygen uptake [Vo(2)peak], 44.4 +/- 1.9 mL/kg fat-free mass/min; mean +/- SE] and 10 postmenopausal obese women (mean age, 57.2 +/- 1.2 years; body mass index, 27.9 +/- 0.5 kg/m(2); VO(2)peak, 39.9 +/- 1.3 mL/kg fat-free mass/min) performed a 40-minute bout of cycling exercise at 50% VO(2)peak. Blood samples were collected for assessment of metabolic variables and 17beta-estradiol concentration at baseline and during aerobic exercise. Breath samples were collected to estimate carbohydrate and fat oxidation using a digital computer-based breath-by-breath exercise analysis system during aerobic exercise. Serum 17beta-estradiol concentration was not significantly different between the men and women subjects at baseline (P > .05). Serum free fatty acid concentration tended to be higher in the men than in the women (P = .07) during the exercise, but the respiratory exchange ratio during exercise was lower in women than in men (P < .05). Fat oxidation adjusted for fat-free mass was higher (P < .05) in women than in men. These results suggest that fat utilization was higher during aerobic exercise in postmenopausal obese women than in obese men and did not depend on resting serum 17beta-estradiol concentration.

Air displacement plethysmography for estimating body composition changes with weight loss in middle-aged Japanese men.

Aim: To examine the degree to which air displacement plethysmography (ADP) can track body composition changes in response to weight loss in obese Japanese men. Method: 50 men, aged 30–65 years with a mean BMI of 30 kg/m2, were included in a 3-month weight loss program. Percentage of fat mass (%FM) was determined by dual energy X-ray absorptiometry (DXA) and ADP at baseline and month 3. Results: With 6.2 ± 4.3 kg of weight loss, %FM, as determined by DXA and ADP, significantly decreased by 3.9 ± 2.9% and 3.9 ± 3.3% respectively. There was no mean difference for change (Δ) in %FM between the two methods. DXA-derived Δ%FM significantly correlated with Δ%FM determined by ADP (R2 = 0.48, p < 0.01). Furthermore, the Bland-Altman plots demonstrated no systematic bias for Δ%FM (r = –0.20, p = 0.17). However, %FM by ADP (r = 0.42) at baseline and Δ%FM by ADP (r = –0.54) were significantly correlated to the differences between Δ%FM by DXA and ADP. Conclusion: These results suggest that ADP is comparably accurate for evaluating Δ%FM when compared with DXA, although there were proportional biases.