Maximal Fat Oxidation and Fuel Use During Exercise
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 40
- 试验地点
- 2
- 主要终点
- Change in maximal fat oxidation
研究概览
简要总结
Fat and carbohydrate are the two main energy stores available as fuel during exercise. It is well known that the exercise intensity and feeding status are the major factors determining the type of fuel used during exercise. During prolonged exercise at low to moderate exercise fat is the primary fuel being used and to improve performance studies has tried to understand strategies to maximize muscle glycogen storage and elevate fat oxidation during exercise. With this strategy they aim for preserving the limited muscle glycogen stores and thus improving endurance performance. In relation to this the maximal fat oxidation (MFO: The highest rate of fat oxidation across all exercise intensities) has been studied as increasing the fat oxidation could decrease the depletion of the glycogen stores. Further it has recently been shown that MFO is related to performance in endurance trained. However the MFO has been found to vary markedly between trained individuals matched on their activity level.
It has been suggested that the diet and subsequent substrate availability during exercise contributes independently to the variation in MFO. However, the measurements have never been evaluated in a trained group with similar aerobic capacity and training status. Therefore, the aim of the study is to investigate the effect of a short term fat rich or carbohydrate rich diet on MFO in well trained men with a high vs. a low MFO. The hypothesis is that 3 days of a fat-rich diet will increase MFO while 3 days of a Carbohydrate rich diet will decrease MFO in both individuals with a high MFO (HiMFO) and a low MFO (LoMFO). Furthermore, it is hypothesized that HiMFO will have a significantly higher MFO after both diets compared to LoMFO.
Lifestyle and physiological factors have been investigated to determine the variation of the MFO capacity. However, these factors can only explain 50% of the interindividual variability in MFO. Despite the critical role of fat oxidation during exercise, few studies have explored the differences in skeletal muscle characteristics between HiMFO and LoMFO. The second aim of the study is thereby to investigate if muscle characteristics can explain the variability in MFO within well-trained males. The hypothesis is that HiMFO will have more favorable muscle characteristics for fat oxidation compared to LoMFO including a higher oxidative capacity, intramuscular triacylglycerol concentration and a higher expression of key enzymes in lipid metabolism.
详细描述
A group of young, healthy and moderate to well-trained males will be recruited for the study. The participants will be separated into 2 groups by stratified randomization consuming either a 3 day Fat rich diet (HiFAT) or a carbohydrate rich diet (HiCHO).
When all participants have completed the study, the results will be analysed by separating the two groups into two subgroups based on the median of the MFO
The study includes 4 visits to out laboratory.
When the participants have read, accepted and signed the plain language statement they will be invited for a screening session in our laboratory which is the first visit. If the participant meet the inclusion and not the exclusion criteria, they will be included in the study and a time schedule for the next three visits will be planned. In the end of the screening the participant will be instructed to full fill a 4-day diet dairy to analyse the participants habitual diet.
For the second visit the participant will meet in the laboratory after an overnight fast and has been asked to avoid alcohol and strenuous exercise 48 hours prior to the test day. The second test starts with a visit to the toilet before a Dual-energy X-ray absorptiometry (DXA) scan and a bioelectrical impedance scan (BIA) is performed to measure the body composition of the participant. After 5 min. of rest, the blood pressure is measured followed by a measurement of the hip and waist circumference. After measuring the blood pressure and body composition the participant will perform a incremental exercise test on a cycle ergometer. The expired air is measured by indirect calorimetry and is used to calculate the maximal fat oxidation and maximal aerobic capacity.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
盲法说明
As the participants receive a specific diet, and have to buy their gloceries themself, it is not possible to mask what kind of diet they consume. They will be randomised into what kind of diet they receive.
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Age: 18 to 40 years
- •Physical activity > 3 times/week
- •Maximal aerobic capacity > 50 mlO2/min/kg
- •BMI < 30 kg/m2
排除标准
- •Aged below 18 years or above 40 years
- •Maximal aerobic capacity < 50 mlO2/kg/min
- •Body mass index > 30 kg/m2
- •Taking any prescription medication influencing metabolism
- •Having existing cardiovascular, metabolic or musculoskeletal conditions that may influence ability to exercise or study outcomes
结局指标
主要结局
Change in maximal fat oxidation
时间窗: Baseline and after three days diet
Change in maximal fat oxidation (gram/min.) from baseline to after 3-day carbohydrate rich or fat rich diet in moderately trained males
次要结局
- Change in muscle triacylglycerol(Baseline and after three days diet)
研究者
Jørn Wulff Helge
Professor
University of Copenhagen