Journal of Exercise Nutrition & Biochemistry最新文献

Purpose: Although the fibroblast growth factor-21 (FGF-21) and irisin roles are well demonstrated in metabolic disease, there have been no reports investigating the effect of resistance exercise on FGF-21 and irisin levels in diabetic skeletal muscles. Therefore, this study aimed to investigate the change of FGF-21 and irisin levels in various skeletal muscles, and their association with muscle strength, following 8 weeks of resistance training using Zucker diabetic fatty rats (type 2 diabetic animal models).

Methods: Twenty-four male lean (Zucker lean control, ZLC) and diabetic (Zucker diabetic fatty, ZDF) rats (age, 8 weeks old) were separated into 3 groups, lean control (ZLC-Con, n=8), diabetic control (ZDF-Con, n=8), and diabetic exercise-trained groups (ZDF-Ex, n=8). The rats in ZDF-Ex were trained to climb a 1-m vertical (85 degrees inclined) ladder with weights. Resistance training was performed with 10 repetitions/day for 12 weeks (3 days/week). The skeletal muscle levels of FGF-21 and irisin were measured using enzyme-linked immunosorbent assays.

Results: The levels of FGF-21 in the soleus (SOL) and extensor digitorum longus muscles of ZDF-Ex were higher (p<0.05) compared to levels in ZDF-Con. Additionally, we found a significantly higher irisin level in the SOL muscles of ZDF-Ex compared to that in ZDF-Con. Moreover, we found that the levels of FGF-21 (R=0.532, p=0.02) and irisin (R=0.498, p=0.03) had significant correlations with grip strength.

Conclusion: Based on these results, resistance training may be an efficient intervention for increasing FGF-21 and irisin levels in type 2 diabetic (T2DM) skeletal muscles.

Purpose: Recent evidence suggests that regular exercise training plays a decisive role in maintaining homeostasis and promoting muscle and skeletal formation. However, the effect of downhill exercise training on osteogenesis-related factors is not well understood.

Methods: Thus, we investigated the effect of uphill and downhill training on ovariectomy (OVX)-induced bone loss. After ovary removal, the exercise method performed included uphill (16 m/min, +15°) and downhill training (16 m/min, -15°) for 60 min/day and 5 days/week, respectively, for 8 weeks.

Results: Our results showed that both uphill and downhill training significantly decreased the body weight, total cholesterol, and creatine kinase (CK) levels in the context of OVX-induced bone loss. On the contrary, levels of an osteogenesis indicator, osteocalcin and alkaline phosphatase were elevated. Consequently, the uphill and downhill training reduced OVX- induced bone loss in the distal femoral metaphysis. Likewise, the bone microstructure in OVX-induced bone loss was enhanced upon training. In particular, the inhibition of RANKL-induced osteoclast formation and osteoclast-specific gene expression improved upon downhill training compared to uphill training.

Conclusion: These results suggest that the uphill and downhill exercise types appeared to positively affect the expression of osteogenesis-related factors along with bone density and microstructure. Particularly, the downhill training has more beneficial effects on the maintenance of homeostasis during bone formation.

Purpose: Postmenopausal women are highly susceptible to diseases, such as obesity, type 2 diabetes, osteoporosis, or skeletal muscle atrophy and many people recognize the need for regular physical activity. Aerobic exercise training is known to improve the oxidative capacity and insulin sensitivity of skeletal muscles. This study aimed to investigate the role of low-intensity aerobic exercise training on skeletal muscle protein degradation or synthesis in the plantaris muscles of high-fat-fed ovariectomized rats.

Methods: Ovariectomized female rats were divided into two groups: a high-fat diet-sedentary group (HFD), and a high-fat diet-aerobic exercise group (HFD+EX). The exercise group exercised aerobically on a treadmill 5 days/week for 8 weeks. The rats progressively ran 30 min/day at 15 m/min, up to 40 min/day at 18 m/min, 0% slope, in the last 4 weeks.

Results: Although aerobic exercise led to significantly increased AMP-activated protein kinase (AMPK) phosphorylation at Thr172, phosphorylation of the mammalian target of rapamycin (mTOR) substrate Thr389 S6K1 level did not decrease. Additionally, even though Akt activity did not increase at Ser473, the atrogin-1 level significantly decreased in the exercise group compared to the non-exercise group. Immunohistochemical staining revealed that high-fat-induced TSC2 protein expression was eliminated in response to aerobic exercise.

Conclusion: These results suggest that aerobic exercise can inhibit skeletal muscle protein degradation, but it cannot increase protein synthesis in the plantaris muscle of high-fat-fed ovariectomized rats. Our findings have implications in understanding skeletal muscle mass maintenance with low intensity aerobic exercise in post-menopausal women.

Purpose: The purpose of this study was to develop a regression model to estimate the heart rate at the lactate threshold (HRLT) and the heart rate at the ventilatory threshold (HRVT) using the heart rate threshold (HRT), and to test the validity of the regression model.

Methods: We performed a graded exercise test with a treadmill in 220 normal individuals (men: 112, women: 108) aged 20-59 years. HRT, HRLT, and HRVT were measured in all subjects. A regression model was developed to estimate HRLT and HRVT using HRT with 70% of the data (men: 79, women: 76) through randomization (7:3), with the Bernoulli trial. The validity of the regression model developed with the remaining 30% of the data (men: 33, women: 32) was also examined.

Results: Based on the regression coefficient, we found that the independent variable HRT was a significant variable in all regression models. The adjusted R2 of the developed regression models averaged about 70%, and the standard error of estimation of the validity test results was 11 bpm, which is similar to that of the developed model.

Conclusion: These results suggest that HRT is a useful parameter for predicting HRLT and HRVT.

Purpose: The purpose of this study was to investigate the effect of hippotherapy and electroencephalography (EEG) neurofeedback on brain function and blood brain-derived neurotrophic factor (BDNF) level in children with attention-deficit or/and hyperactivity disorder (ADHD).

Methods: Sixteen children with ADHD participated in this study and were randomly divided into 2 groups, a 1-time hippotherapy group (W1G, n = 8) and a 2-time hippotherapy group (W2G, n = 8). All the participants attended 8 weeks of hippotherapy program in the primary training, and then 7 children with ADHD attended 8 weeks of hippotherapy program combined with neurofeedback training in the secondary training. Blood BDNF levels were measured, and functional magnetic resonance imaging (fMRI) was performed. The EEG neurofeedback training program was used to train and measure psychological factors.

Results: The combined effect of hippotherapy and neurofeedback on BDNF level showed a decreased tendency in W1G (pretraining, 1766.03 ± 362.54 pg/ml; posttraining, 1630.65 ± 276.70 pg/ml). However, the BDNF level of W2G showed an increased tendency (pretraining, 1968.28 ± 429.08 pg/ml; posttraining, 1976.28 ± 425.35 pg/ml). Moreover, combined training showed a significant group x repetition interaction in W1G (pretraining, 1436.57 ± 368.76 pg/ml; posttraining, 1525.23 ± 346.22 pg/ml; F = 3.870, p = 0.039). fMRI results showed that the left thalamus activity in both groups had a decreased tendency and a significantly lower change in W2G than in W1G (p < 0.05).

Conclusion: This study confirmed a significant increase in blood BDNF level after combined training, which may induce brain function improvement in children with ADHD.

Purpose: Advanced glycation end products (AGEs) are non-enzymatic modifications of proteins or lipids after exposure to sugars. In this review, the glycation process and AGEs are introduced, and the harmful effects of AGEs in the aging process are discussed.

Methods: Results from human and animal studies examining the mechanisms and effects of AGEs are considered. In addition, publications addressing means to attenuate glycation stress through AGE inhibitors or physical exercise are reviewed.

Results: AGEs form in hyperglycemic conditions and/or the natural process of aging. Numerous publications have demonstrated acceleration of the aging process by AGEs. Exogenous AGEs in dietary foods also trigger organ dysfunction and tissue aging. Various herbal supplements or regular physical exercise have beneficial effects on glycemic control and oxidative stress with a consequent reduction of AGE accumulation during aging.

Conclusion: The inhibition of AGE formation and accumulation in tissues can lead to an increase in lifespan.

Purpose: This study examined the effects of daily physical activity level on health-related factors according to gender and identified age-specific differences among Korean adults.

Methods: Using data from the Korea National Health and Nutrition Examination Survey VI (2014-2015), we selected adults aged 19-64 years who participated in both a health examination and health interview survey. The study included 6,457 participants 19-64 years of age (2,611 men, 3,846 women).

Results: Assessment of the differences in health-related factors according to age and physical activity in men and women by repeated two-way analysis of variance (ANOVA) revealed significant interaction effects on total cholesterol (TC) and triglyceride (TG) levels and diastolic blood pressure (DBP) in male participants, but there were no significant interaction effects for any health-related factors in female participants. The group of female participants aged 40-64 years with daily physical activity levels over 200 kcal showed a significantly increased prevalence of 46% for dyslipidemia compared to that in female participants with daily physical activity levels below 200 kcal. Physical activity was positively correlated with weight and high-density lipoprotein cholesterol (HDL-C) levels in men 19-39 years of age, compared to weight, waist circumference (WC), body mass index (BMI), and DBP in men 40-64 years of age, and weight, WC, BMI, glycated hemoglobin (HbA1c) and triglyceride (TG) levels in women 19-39 years of age. In women 40- 64 years of age, physical activity was especially significantly positively correlated with weight, BMI, HDL-C and negatively correlated with fasting glucose and TG levels.

Conclusion: In male and female participants, the 40-64-year age group showed negative results for health-related factors compared to those in the 19-39-year age group. The higher the weight, WC, BMI, the higher is the physical activity level. Physical activity levels were significantly positively correlated with health-related variables.

Purpose: The purpose of this study was to determine whether exercise or/and cold exposure regulate mitochondria biogenesis-related gene expression in soleus and inguinal adipose tissue of mice.

Methods: Forty ICR 5-week old male mice were divided into four groups: thermoneutrality-untrained (23 ± 1 °C in room temperature, n=10), cold-water immersion (24 ± 1 °C, n=10), exercise in neutral temperature (34 ± 1 °C, n=10), and exercise in cold temperature (24 ± 1 °C, n=10). The mice performed swimming exercise (30 min to 60 min, 5 times) for 8 weeks. After 8 weeks, we confirmed mitochondrial biogenesis-related gene expression changes for peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), nuclear respiratory factors 1 (NRF1), and mitochondrial transcription factor A (Tfam) in soleus muscle and inguinal adipose tissue, and the related protein expression in soleus muscle.

Results: In soleus muscle, PGC-1α expression significantly increased in response to cold exposure (p = 0.006) and exercise (p = 0.05). There was also significant interaction between exercise and cold exposure (p = 0.005). Only exercise had a significant effect on NRF1 relative expression (p=0.001). Neither cold exposure nor the interaction showed significant effects (p = 0.1222 and p = 0.875, respectively). Relative Tfam expression did not show any significant effect from exercise. In inguinal adipose tissue, relative PGC-1α expression did not significantly change in any group. NRF1 expression showed a significant change from exercise (p = 0.01) and cold exposure (p = 0.011). There was also a significant interaction between exercise and cold exposure (p = 0.000). Tfam mRNA expression showed a significant effect from exercise (p=0.000) and an interaction between exercise and cold exposure (p=0.001). Only temperature significantly affected PGC-1α protein levels (p=0.045). Neither exercise nor the interaction were significant (p = 0.397 and p = 0.292, respectively). NRF1 protein levels did not show a significant effect in any experimental treatments. Tfam protein levels showed a significant effect in the exercise group (p=0.012), but effects of neither cold exposure nor the interaction were significant (p = 0.085 and p=0.374, respectively).

Conclusion: Exercise and cold exposure promoted increased expression of mitochondrial biogenesis- related genes in soleus muscle. Only cold exposure had a significant effect on PGC-1α protein expression and only exercise had a significant effect on Tfam protein expression. In inguinal adipose tissue, there was interaction between exercise and cold exposure in expression of mitochondrial biogenesis-related genes.

Purpose: Although previous studies have investigated the association between physical activity and various health outcomes, limited information is available on the effect of meeting new governmental guidelines for physical activity on the risk of mortality in Korean adults. This study aimed to examine the prospective association between meeting these guidelines and all-cause mortality during an 8-year follow-up using a large nationwide sample of middle-aged and older adults in Korea.

Methods: This prospective study was conducted based on the Korean Longitudinal Study of Ageing. The study participants included 9,177 adults aged 45 years or older at baseline, and all participants were monitored in a 2-year cycle during an 8-year period (70,873 person-years). The risk of mortality was analyzed by determining physical activity levels using the Cox proportional hazard models, and the hazard ratio (HR) and 95% confidence interval (CI) were estimated using Cox models.

Results: A statistically significant effect of physical activity on the reduced risk of mortality was observed in cases in which the participants met the guidelines compared to the inactive group (HR: 0.68, 95% CI: 0.58-0.81 vs. the inactive group). A strong association between meeting the recommended physical activity levels and the reduced risk of mortality was also found for non-smokers (HR: 0.62; 95% CI: 0.51-0.76 vs. the inactive group), but not for current smokers (HR: 0.93; 95% CI: 0.67-1.29 vs. the inactive group).

Conclusion: Meeting physical activity guidelines was associated with a decreased risk of all-cause mortality for Korean adults. Our results also suggest that smoking reduces the protective effect of physical activity on the risk of mortality.