Influence of Pre-exercise Nutrition on Exercise Fuel Use in Males and Females
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- Whole-body carbohydrate oxidation
研究概览
简要总结
This study will investigate whether pre-exercise nutrition influences sex differences in fuel utilization during endurance exercise. Twenty-four recreationally active adults (12 females and 12 males) will complete three experimental exercise trials in a randomized, counterbalanced crossover design. Before each trial, participants will consume either a carbohydrate beverage, a protein-based beverage, or a flavour-matched non-caloric beverage representing the fasted condition. Thirty minutes later, participants will complete 90 minutes of moderate-intensity cycling followed by a cycling time-to-task-failure test. Whole-body carbohydrate and fat oxidation, exogenous substrate oxidation, blood metabolites, and exercise performance will be assessed.
详细描述
Sex differences in substrate utilization during fasted endurance exercise are well established, with females generally demonstrating greater reliance on fat oxidation and lower carbohydrate utilization than males. However, exercise is frequently performed following nutrient ingestion, and it remains unclear whether sex differences in substrate utilization persist when carbohydrate or protein is consumed before exercise.
This randomized, counterbalanced crossover study will compare three pre-exercise nutritional conditions: carbohydrate (CHO), protein (PRO), and fasted/placebo (FAST). Participants will complete each condition separated by a minimum three-day washout. Following an overnight fast, participants will consume the assigned beverage and rest for 30 minutes before completing 90 minutes of cycling at 65% of VO2peak. This will be followed by a two-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.
The primary objective is to determine whether pre-exercise nutrition modifies sex differences in whole-body carbohydrate and fat oxidation and exogenous substrate oxidation during exercise. A secondary objective is to determine the effects of pre-exercise nutrition and sex on subsequent exercise performance.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Participating in ≥150 minutes of moderate-to-vigorous physical activity per week
- •VO₂peak classified as "good" or above based on American College of Sports Medicine normative values: >35.0 mL/kg/min for females and >39.0 mL/kg/min for males
- •Body mass index (BMI) between 18 and 27 kg/m²
- •Participating in 3-5 structured exercise sessions per week
- •Weight stable, defined as within ±2 kg for at least 6 months
- •Non-smoker
- •Females must be eumenorrheic
排除标准
- •Polycystic ovarian syndrome (PCOS) or endometriosis Current use of oral contraceptives or oral contraceptive use within the previous 3 months Diagnosed cardiovascular or metabolic disease Hypergonadism or hypogonadism Use of medications for management of blood glucose or lipid metabolism Pregnant or <12 months postpartum Lactating or breastfeeding within 3 months of study commencement Menopausal Recreational tobacco smoking Inability to complete the study exercise protocols or comply with pre-trial dietary or physical activity controls Use of medications that may affect substrate metabolism, including corticosteroids or non-steroidal anti-inflammatory drugs (NSAIDs) Currently following a low-carbohydrate diet, such as a ketogenic or Atkins diet
研究组 & 干预措施
Protein (PRO)
Participants will consume a protein-based beverage following an overnight fast. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.
干预措施: Pre-exercise protein beverage (Dietary Supplement)
Fasted (FAST)
Participants will remain fasted and consume a non-caloric, flavour-matched beverage. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.
干预措施: Fasted control beverage (Other)
Carbohydrate (CHO)
Participants will consume a carbohydrate beverage following an overnight fast. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.
干预措施: Pre-exercise carbohydrate beverage (Dietary Supplement)
结局指标
主要结局
Whole-body carbohydrate oxidation
时间窗: During the 90-minute exercise bout
Whole-body carbohydrate oxidation will be calculated from oxygen consumption (VO2) and carbon dioxide production (VCO2) measured by indirect calorimetry during 90 minutes of moderate-intensity cycling. Carbohydrate oxidation will be compared between the carbohydrate, protein, and fasted conditions and between females and males.
Whole-body fat oxidation
时间窗: During the 90-min exercise bout
Whole-body fat oxidation will be calculated from VO2 and VCO2 measured by indirect calorimetry during 90 minutes of moderate-intensity cycling. Fat oxidation will be compared between the carbohydrate, protein, and fasted conditions and between females and males.
Exogenous glucose oxidation
时间窗: During the 90-min exercise bout
Exogenous glucose oxidation will be determined during the carbohydrate condition using breath 13CO2 enrichment following ingestion of \[U-13C6\]-D-glucose. Breath samples will be analyzed by isotope ratio mass spectrometry, and exogenous glucose oxidation will be calculated using 13CO2 enrichment and carbon dioxide production.
Exogenous leucine oxidation
时间窗: During the 90-min exercise bout
Exogenous leucine oxidation will be determined during the protein condition using breath ¹³CO₂ enrichment following ingestion of L-\[1-¹³C\]leucine. Breath samples will be analyzed by isotope ratio mass spectrometry, and exogenous leucine oxidation will be calculated using breath ¹³CO₂ enrichment and carbon dioxide production.
次要结局
- Time to task failure(Immediately following the 90-min exercise bout)
研究者
Jenna Gillen
Associate Professor
University of Toronto