Sheila Costford, PhD

Transcription

1 Fueling for Exercise Sheila Costford, PhD INTRODUCTION Case Studies 45- min aerobics class participant: Klein strength training client: Abraham 90- min tennis match champ: Vanessa marathon runner: Carlos Website to calculate estimated calorie expenditure: Assumptions for 45- min aerobics class participant: Gender: female Age: 45 years Height: 5 4 Weight: 145 lbs BMI: 24.9 kg/m 2 Calories burned during workout: 288 kcal Proficiency: intermediate Workout for 45- min aerobics class participant: 40 min low impact aerobics 5 min stretch Indoors, air- conditioned Assumptions for strength training client: Gender: male Age: 25 years Height: 6 1 Weight: 185 lbs BMI: 24.4 kg/m 2 Calories burned during workout: 441 kcal Proficiency: advanced Workout for strength training client: 5 min walk on treadmill at 3.0 mph 45 min vigorous weight lifting 5 min stretch Indoors, air- conditioned

2 Assumptions for 90- min tennis match champ: Gender: female Age: 28 years Height: 5 7 Weight: 150 lbs BMI: 23.5 kg/m 2 Calories burned during workout: 651 kcal Proficiency: advanced Workout 90- min tennis match champ: 90 min singles tennis match Outdoors, sunny, hot & humid Assumptions for marathon runner: Gender: male Age: 57 years Height: 5 10 Weight: 140 lbs BMI: 20.1 kg/m 2 Calories burned during workout: 2801 kcal Proficiency: intermediate Workout for marathon runner: Outdoors, cool & dark to start, hot & sunny hot to finish 3:50 marathon (6.8 mph; 8:47 pace) PART 1 Before Should I fuel before I exercise? A. No, you ll get sick B. No, you ll burn more fat calories if you exercise fasted C. Yes, you ll burn more fat calories if you exercise fueled D. We don t know it has not been scientifically determined Fueling before exercise: Prevents low blood sugar (light- headedness, fatigue, blurred vision, indecisiveness) Settles your stomach (absorb some gastric juices) & prevent hunger Provides carbohydrate for your muscles to use Allows you to exercise at a higher intensity, so you can burn more calories Considerations for fueling before exercise: Type of activity: more jostling, higher chance of gastrointestinal (GI) problems Training status: beginners tend to have more GI problems Age: older athletes tend to have more GI problems Gender: women tend to have more GI problems Stress: higher stress levels, higher chance of GI problems Intensity: higher intensity, higher chance of GI problems Macromolecule component: meals with a high fat content may make you feel queasy Fiber: although good for every day eating, eating a lot of fiber prior to a workout could cause GI distress Sugar alcohols: these sweetners (often added to protein powder) cause gas & diarrhea in high amounts Hydration status: the more hydrated you are, the better you will perform (to a point)

3 Hormonal changes: hormones (such as those associated with menses) can cause GI distress Chronic diseases (e.g., IBS, celiac): higher risk for GI distress Calories/Carbohydrate Short workout: half the number of calories estimated to be burned during the workout Long workout: 2 kcal carbohydrate per pound body weight (if BMI in healthy range) (ACSM, ADA, Dieticians of Canada) Case study #1: aerobics class How long in advance? Start at 1 h and see how it feels adjust if necessary Case study #2: strength training session How long in advance? Start at 1 h and see how it feels adjust if necessary Case study #3: tennis match How long in advance? 1-2 h, depending on nerves & digestibility of fuel ; electrolytes; consider liquid fuel Case study #4: marathon How long in advance? breakfast 3 h in advance; snack 1 h in advance adjust if necessary How much? 2 kcal carbohydrate per pound body weight (if BMI in healthy range) What type of food/nutrient? Carbohydrate with a little bit of protein and/or fat PART 2 During General principles Electrolytes: If workout is >90 min If sweating is excessive (heat, humidity, hyperhidrosis) Carbohydrate: If workout is >60 min When to fuel during exercise If workout is moderate to intense and h: Start fueling in the 2 nd hour with g ( kcal) carbohydrate per hour If workout is mild to moderate and >2.5 h: Start fueling in the 2 nd hour with 30 g (120 kcal) carbohydrate per hour If workout is moderate to intense and >2.5 h: g ( kcal) carbohydrate per hour Higher intake associated with better performance to a point

4 Who should fuel during exercise? A. Case #1: aerobics class B. Case #2: strength training workout C. Case #3: tennis match (electrolytes, maybe carbohydrate) D. Case #4: marathon (electrolytes, carbohydrate) Sports replacement drinks Electrolytes Glucose (sugar) Carbohydrate sources Natural: fruit, dried fruit, homemade granola bars Commercial: gels, chews, sport beans Other: candy Caffeine Tolerance: a little can improve performance, too much can make you jittery Threshold: people who regularly consume caffeine with not have as great an improvement in performance GI system: caffeine has a laxative effect time it appropriately Practise: don t try caffeine for the first time during a race or an important event 1.5 mg per pound body weight (if BMI in healthy range) pre- exercise PART 3 After Carboloading Increased glucose uptake into muscles (therefore increased glycogen storage) The longer and more intense the workout, the better the carboloading effect (carboload after intense workouts of >90 min) Best effect within first hour post- exercise, but elevated rate of glucose uptake for 24 h post- exercise 0.5 g carbohydrate per pound body weight (healthy BMI) g protein per pound body weight (healthy BMI) to enhance effect of carboloading Protein Should I eat protein right after a strength workout? Won t hurt you, but won t help Will it help with hypertrophy? No. Make sure to have enough protein during the day (before you go to sleep) the majority of muscle repair takes place while you re sleeping. Case study #1: aerobics class How long after? Within an hour or so (don t wait until you get hungry) Case study #2: strength training session How long after? Within an hour or so (don t wait until you get hungry) Case study #3: tennis match How long after? Within an hour ; electrolytes

5 Case study #4: marathon How long after? Within an hour How much? 0.5 g carbohydrate g protein per pound body weight (healthy BMI) ; electrolytes Burning Questions Can I drink alcohol? Yes, if you are rehydrated post- exercise (pale yellow urine) and you rehydrate after alcohol consumption (i.e., before going to sleep) Is it better to eat food or drink a smoothie? Solid food will make you feel fuller (good for weight maintenance); drinking a smoothie might be easier on your GI system if you are having trouble with it What does everything taste so good??? Glucose transporters in your mouth are upregulated post- exercise Good resource for professionals new to sports nutrition: Nancy Clark s Sports Nutrition Guidebook, 5 th Edition