| Purpose:The aim of this study was to observe the effect of supplementation of marine structured lipids(MSL)for 8 weeks on the aerobic exercise capacity and moderateintensity exercise endurance in ordinary male college students.The oxidation of the substrates(carbohydrate and fat)during moderate-intensity aerobic exercise,the fatty acid distribution and the antioxidant enzyme activity in erythrocyte membrane and the blood lipids were detected to explore the possible mechanism of the effect of MSL supplementation on exercise capacity.Methods:39 ordinary male college students over 20 years old without special sports were selected as subjects.The subjects were randomly divided into 2 groups by the randomized controlled double-blind experimental design.The experimental group(MSL,19 persons)was supplemented with MSL,and the daily supplemented MSL contained 600 mg of EPA and 260 mg of DHA.The control group(PLA,20 persons)was supplemented with the same amount of corn oil without EPA and DHA.The intervention time were 58 days(8 weeks+2 days).Before and after the intervention,the subjects’ fasting and quiet venous blood were collected to determine the fatty acid composition,antioxidant enzyme activity,lipid peroxidation products in the erythrocyte membrane and the lipids in serum.Height and weight were measured to calculate body mass index(BMI).The body composition was measured including fat weight and percentage,muscle weight and bone density.The maximum oxygen uptake(VO2max)and ventilatory anaerobic threshold(VAT)were tested.The value of VO2max obtained from the pre-intervention test was used to caculate the intensity of 65%VO2max for the constant load exercise test.The time to exhaustion of the constant load test was recorded and the breathing gas was collected to analyze the oxidation rate of carbohydrate,fat and the respiratory exchange rate(RER)before exercise and at 20th min,40th min and 60th min during the exercise.Results:(1)The VAT was increased significantly in MSL group after the intervention and the change(increase)of the VAT in MSL group was significantly different from the change(decrease)of the VAT in PLA group after the intervention.(2)The time to exhaustion of the constant load exercise was significantly longer in MSL group after the intervention and was significantly longer than that in PLA group after the intervention,and the change(extension)of the time to exhaustion was significantly greater than that in PLA group.(3)The oxidation rate of carbohydrate was reduced significantly at each time points during the exercise after the intervention in MSL group,and was significantly reduced only at 20th min and 60th min during the exercise after the intervention in PLA group.The oxidation rate of carbohydrate at 40th min during the exercise in MSL group was significantly lower than that in PLA group after the intervention.The change(decrease)of the oxidation rate of carbohydrate at 20th min and 40th min during the exercise in MSL group was significantly greater than that in PLA group after the intervention.(4)The oxidation rate of fat was increased significantly at each time points during the exercise after the intervention in MSL group,and was increased significantly only at 20th min during the exercise after the intervention in PLA group.The oxidation rate of fat at 20th and 40th min during the exercise in MSL group was significantly higher than that in PLA group after intervention.The change(increase)of the oxidation rate of fat at 20th min and 40th min during the exercise in MSL group was significantly greater than that in PLA group after the intervention.(5)The RER was reduced significantly at each time points during the exercise after the intervention in MSL group,while it was reduced significantly only at 20th min after the intervention in PLA group.The RER at each time points during the exercise in MSL group was significantly lower than that in PLA control group after the intervention.The change(decrease)of the RER at each time points during the exercise in MSL group was significantly greater than that in PLA group after the intervention.(6)The distribution percentage of EPA and DHA in the erythrocyte membrane was increased significantly after the intervention in MSL group,and it was significantly higher than that in PLA group after the intervention.(7)The activities of the antioxidant enzymes(GPX,SOD,CAT)in the erythrocyte membrane were increased significantly and the content of the oxidation product(MDA)was decreased significantly after the intervention in MSL group.(8)The concentrations of TG and LDL-C in serum were decreased significantly after the intervention in MSL group.(9)The weight and percentage of the fat were decreased significantly after the intervention in MSL group.Conclusion:MSL supplementation for 8 weeks increases the oxidation rate of fat and reduces the oxidation rate of carbohydrates during moderate-intensity exercise to save the utilization of glycogen during exercise,thereby improve the aerobic capacity and endurance of moderate-intensity exercise.The mechanism may be related to the fact that MSL improve the composition of erythrocyte membrane fatty acids,enhance the erythrocyte membrane antioxidant capacity,and have protective effects on erythrocytes. |
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