Impact of Maximal Fat Oxidation Intensity Exercise on Arterial Stiffness in Overweight/Obesity Young Men / 中国运动医学杂志

Objective To assess the impact of maximal fat oxidation intensity(FATmax) exercise on arterial stiffness in overweight/obesity young men.Method Thirty two overweight/obesity young men (BMI≥25 kg/m2) without the habit of doing exercises,were divided into an exercise group (n=16) and a control group (n=16) randomly.The exercise group completed a 12-week walk/run(FATmax intensity,3-5 times/week,40-60 min/time) intervention,while the control group maintained normal life style without regular exercise.The body composition,cardiopulmonary function (VO2max),C reactive proteins (CRP) and blood hemodynamic were measured,and the brachial-ankle pulse wave velocity(baPWV) was observed to assess the arterial stiffness before and after the 12-week intervention.Results Significant decrease was observed in the average weight,body mass index,body fat mass,body fat percentage,baPWV,CRP,platelet/lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) (P＜0.05),while significant increase was found in the average VO2max and HDL-C(P＜0.05) after the training.After the intervention,the change in baPWV(△) was positively associated with △ CRP(r=0.604),△ NLR(r=0.535) and △ WBC (white blood count) (r=0.406) (P＜0.05,n=32),but negatively correlated with △ VO2max (r=-0.660,P＜0.05,n=32).Conclusion FATmax intensity aerobic exercise is effective to downregulate the inflammation,and improve aerobic fitness and vascular function.However,the potential mechanism of arterial stiffness improvement following exercise needs further study.

Effect of pre-exercise carbohydrate availability on fat oxidation and energy expenditure after a high-intensity exercise

The aim of this study was to test the hypothesis that reduced pre-exercise carbohydrate (CHO) availability potentiates fat oxidation after an exhaustive high-intensity exercise bout. Eight physically active men underwent a high-intensity exercise (∼95% V̇O2max) until exhaustion under low or high pre-exercise CHO availability. The protocol to manipulate pre-exercise CHO availability consisted of a 90-min cycling bout at ∼70% V̇O2max + 6 × 1-min at 125% V̇O2max with 1-min rest, followed by 48 h under a low- (10% CHO, low-CHO availability) or high-CHO diet (80% CHO, high-CHO availability). Time to exhaustion was shorter and energy expenditure (EE) lower during the high-intensity exercise in low- compared to high-CHO availability (8.6±0.8 and 11.4±1.6 min, and 499±209 and 677±343 kJ, respectively, P<0.05). Post-exercise EE was similar between low- and high-CHO availability (425±147 and 348±54 kJ, respectively, P>0.05), but post-exercise fat oxidation was significantly higher (P<0.05) in low- (7,830±1,864 mg) than in high-CHO availability (6,264±1,763 mg). The total EE (i.e., exercise EE plus post-exercise EE) was similar between low- and high-CHO availability (924±264 and 1,026±340 kJ, respectively, P>0.05). These results suggest that a single bout of high-intensity exercise performed under low-CHO availability increased post-exercise fat oxidation, and even with shorter exercise duration, both post-exercise EE and total EE were not impaired.

Physiological and biochemical effects of kurort healthy walking / 体力科学

<p>Kurort healthy walking is started to spread across the country as an exercise for health promotion utilizing a rich natural environment in Japan. It is characterized by walking on sloping terrain with mild body cooling (a decrease of approximately 2°C in skin temperature). The body cooling induces physiological and biochemical changes such as the decrease in heart rate and increase in energy metabolism. Although the characteristics of kurort healthy walking are a decrease of approximately 2°C in skin temperature, to our knowledge, no study has focused on its effects on the heart rate or metabolism during exercise. This review focuses on mild body cooling and summarises the effects of kurort healthy walking on physiological and biochemical parameters.</p>

Influence of four weeks of n-3 polyunsaturated fatty acid supplementation on fat metabolism during prolonged exercise / 体力科学

Glycogen is an important source of energy production during endurance exercise, such as marathon. Due to limited storage of glycogen in muscle and liver, augmentation of fat oxidation is known to delay depletion of muscle glycogen, leading to improvement of endurance performance. N-3 polyunsaturated fatty acids (n-3 PUFA) resulting from the form of fish has shown to enhance fat oxidation at rest. However, effect of n-3 PUFA on substrate metabolism during prolonged exercise remains unclear. The present study was designed to investigate whether dietary n-3 PUFA enhances fat oxidation during exercise and endurance performance. Thirteen healthy men were divided into n-3 PUFA group [n=6, 6g/day of fish oil; 1,800mg eicosapentaenoic acid (EPA), 2,700mg docosahexiaenoic acid (DHA)] or CON group [n=7, 6g/day of olive oil]. The subjects ingested each supplement for 4-weeks. Before and after the treatment period, a 60-min pedaling exercise at 65% of maximal oxygen uptake followed by 5 km-time-trial was conducted. Resting concentrations of serum EPA and DHA, EPA/AA were significantly elevated in the n-3 PUFA group only. After supplementation period, the n-3 PUFA group increased significantly exercise-induced elevations of serum free fatty acids and glycerol concentrations, and lowered respiratory exchange ratio during a 60-min pedaling exercise. Similar changes were not observed in the CON group. However, treatment with n-3 PUFA did not affect significantly result of 5km-time-trial. Four-week supplementation of n-3 PUFA increased exercise-induced lipolysis and fat oxidation during prolonged exercise. However, the augmented fat metabolism did not affect endurance performance.

Maximal Fat Oxidation Rate during Exercise in Korean Women with Type 2 Diabetes Mellitus

BACKGROUND: The purpose of this study was to determine the appropriate exercise intensity associated with maximum fat oxidation, improvement of body composition, and metabolic status in Korean women with type 2 diabetes mellitus (T2DM). METHODS: The study included a T2DM group (12 women) and a control group (12 women). The groups were matched in age and body mass index. The subjects performed a graded exercise test on a cycle ergometer to measure their maximal fat oxidation (Fatmax). We also measured their body composition, metabolic profiles, and mitochondrial DNA (mtDNA). RESULTS: The exercise intensity for Fatmax was significantly lower in the T2DM group (34.19% maximal oxygen uptake [VO2 max]) than the control group (51.80% VO2 max). Additionally, the rate of fat oxidation during exercise (P<0.05) and mtDNA (P<0.05) were significantly lower in the T2DM group than the control group. The VO2 max level (P<0.001) and the insulin level (P<0.05) were positively correlated with the rate of fat oxidation. CONCLUSION: The results of this study suggest lower exercise intensity that achieves Fatmax is recommended for improving fat oxidation and enhancing fitness levels in Korean women with T2DM. Our data could be useful when considering an exercise regimen to improve health and fitness.

Fuctional Relationship between Rate of Fatty Acid Oxidation and Carnitine Palmitoyl Transferase I Activity in Various Rat Tissues

Lipids play many structural and metabolic roles, and dietary fat has great impact on metabolism and health. Fatty acid oxidation rate is dependent on tissue types. However there has been no report on the relationship between the rate of fatty acid oxidation and carnitine transport system in outer mitochondrial membrane of many tissues. In this study, the rate of fatty acid oxidation and carnitine palmitoyltransferase (CPT) I activity in the carnitine transport system were measured to understand the metabolic characteristics of fatty acid in various tissues. Palmitic acid oxidation rate and CPT I activity in various tissues were measured. Tissues were obtained from the white and red skeletal muscles, heart, liver, kidney and brain of rats. The highest lipid oxidation rate was demonstrated in the cardiac muscle, and the lowest oxidation rate was in brain. Red gastrocnemius muscle followed to the cardiac muscle. Lipid oxidation rates of kidney, white gastrocnemius muscle and liver were similar, ranging from 101 to 126 DPM/mg/hr. CPT I activity in the cardiac muscle was the highest, red gastrocnemius muscle followed by liver. Brain tissue showed the lowest CPT I activity as well as lipid oxidation rate, although the values were not significantly different from those of kidney and white gastrocnemius muscle. Therefore, lipid oxidation rate was highly (p< 0.001) related to CPT I activity. Lipid oxidation rate is variable, depending on tissue types, and is highly (p< 0.001) related to CPT I activity. CPT I activity may be a good marker to indicate lipid oxidation capacity in various tissues.