Fit Facts: Fueling the body for your swim, bike and run. A brief physiology lesson.

To understand how the body obtains the energy it needs to make it “go”, a useful analogy for how a car and the human body obtain the energy to make them “go.” In an automobile engine, the proper mixture of gasoline fuel with oxygen ignites to provide the energy necessary to drive the pistons. Various gears and linkages harness this energy to turn the wheels, and increasing or decreasing the energy supply either speeds up or slows down the engine. similarly, the human body must continuously be able to extract the energy from its fuel and harness this energy to perform its many complex functions.

How the body gets energy from food
During exercise, the ability to swim, bike, run long distances is determined largely by the body’s ability to extract energy from food nutrients and transfer it to the contractile elements of skeletal muscle. This transfer occurs through thousands of complex chemical reactions that require a continual supply and utilization of oxygen. Such oxygen-requiring reactions are termed aerobic. In contrast, anaerobic chemical reactions generate energy rapidly for short periods (less than 90 seconds in duration) and do not require oxygen. This rapid method of energy transfer is crucial for maintaining a high standard of performance in activities requiring all-out bursts of exercise such as sprinting in track and swimming, or stop-and-go activities like soccer, basketball, and tennis. Most activities are not purely aerobic or anaerobic, but are classified on an anaerobic-to-aerobic continuum. Depending upon the intensity and duration of the effort, these activities will use short-term, immediate, and long-term sources of energy derived from the foods we ate.

This energy is not transferred directly to our cells for biologic work. Instead, the chemical energy trapped within the bonds of carbohydrates, fats and proteins (the nutrients foods are made of) is used to produce the energy-rich compound adenosine triphosphate (ATP) through complex, enzymaticaly-controlled reactions. Carbohydrate is the only nutrient whose stored energy can be used to generate ATP anaerobically. This is important in vigorous exercise that requires rapid energy release.

The sprinter vs the marathoner.
For the sprinter who is exercising at a maximal level of intensity and for the weight lifter, an immediate energy source is necessary for performance. This comes from high-energy phosphate compounds (derived from ATP) and carbohydrates (glycogen) already stored in your muscles. During the first few seconds of an anaerobic exercise, ATP and its derivatives creatine phosphate (CP), and adenosine diphosphate (ADP) work like tiny, supercharged battery packs to supply your muscles with immediate energy. After the first few seconds, the longer you can continue exercising, the more heavily your muscles will depend upon carbohydrate stores. When these stores are depleted, muscle fatigue and exhaustion sets in. When we eat in relationship to when we exercise is important.

The marathon runner, in contrast to the sprinter, is exercising at a submaximal intensity level. Exercise intensity is usually light-to-moderate and remains relatively stable throughout the exercise period. This “steady state” represents a balance between the energy required by the working muscles and the rate of ATP production through aerobic metabolism.

During endurance exercise, carbohydrate supplies about one-half to three-quarters of the body’s energy requirements. With prolonged endurance exercise, there is a shift to a greater use of fats as a primary fuel source. This results in a decreased rate of utilization of both carbohydrate (glucose) and muscle glycogen stores. Despite the fact that fats are predominately used by muscle during endurance exercise of moderate intensity, the rate at which fats break down to provide sufficient energy for prolonged periods of time cannot occur if your diet lacks adequate carbohydrate intake. It is therefore important to eat a well-balanced diet.

Triathlon Training Fit Facts: Refueling After Exercise

As triathletes, a lot of our training includes high-intensity workouts or workout sessions that lasts more than 60 minutes. Refueling your body post-exercise is most important for recovery. I think the following tips regarding food & liquid replacement are helpful. Enjoy your workouts!

• Understand why your body needs refueling.
During exercise your body breaks down tissues and uses energy (primarily carbohydrates) stored in the blood, liver and muscle. Replenishing the energy lost in the muscle (stored as glycogen) is essential for muscle recovery. Eating properly post-exercise is crucial to ensuring that your subsequent workouts are productive and enjoyable.

• Learn why fluid replacement is essential.
The harder and longer you exercise, the more fluid you lose through perspiration and exhalation. When it’s extremely hot or humid, keeping hydrated is more difficult than staying hydrated in cooler temperatures. Since sweat doesn’t evaporate quickly in humid weather, it’s very easy to get overheated.

• Calculate how much to drink.
The American College of Sports Medicine (ACSM) recommends drinking 21/2 - 5 cups (20-40 ounces) of fluid per hour during exercise. After exercise, drink 2-3 cups (16-24 ounces) of fluid per pound of body weight lost through sweat. To help you get an idea of the amount of fluid lost, weigh yourself before and after intense workouts and record the difference.

• Figure out what to drink.
ACSM recommends drinking water when your training session lasts less than 60 minutes. If it’s longer, use a 4-8% carbohydrate sports drink.

• Know when to refuel with carbohydrates.
If you swim, bike or run at a modest intensity for 30-60 minutes three to five times per week, you can maintain adequate carbohydrate stores by eating a balanced diet. If you train harder or longer at a time, your muscles need to be refueled with carbohydrates immediately after exercising and again at the next meal or snack. This practice can ensure that carbohydrates stored in the muscle are consistently replenished.

• Choose the right type of carbohydrate.
Carbohydrates in liquid form, such as sports drinks or juices, can be easier to digest than solid foods post-exercise. However, power bars, or bagels make great food choices.

• Why you also need protein.
Protein is an important building block for muscle. Eating proteins and complex carbohydrates within one hour after exercising can enhance insulin response, which encourages resynthesis of muscle glycogen.

• Know how much protein to eat.
Most experts recommend eating carbohydrates and protein in a ratio of 3:1 or 4:1 post-exercise. An example would be 3 servings of grains plus 1 serving of turkey/meat.

• Realize when you need sodium.
When training in high heat and humidity, sodium losses can be as much as 10 grams per day. Several hours of exercise in cool temperatures will also deplete sodium levels.

• Learn what foods contain sodium.
Sports drinks that contain electrolytes (sodium and potassium) as well as whole foods that contain a significant amount of sodium will help replenish the sodium lost during a training session.

Triathlon Fit Facts: 10 Reasons Why Warming Up is Important

Musculoskeletal injuries and medical problems can occur from participating in physical activity and exercise, however the benefits far outweigh the risks. You can decrease your risk of injury by gradually working up to a desired level of activity and by adequately warming up the muscles and joints prior to exercise.

Here’s why a 5 minute warm-up prior to activity is important.

1. Warming up increases the break down of oxyhemoglobin, a chemical com-plex of oxygen and hemoglobin. This process results in the release of oxygen from the blood, enhancing the delivery of oxygen to the exercising muscle.
   
   
2. Warming up increases body temperature. An elevation in body temperature pro-duced by warming up reduces the potential for skeletal muscle and connective tissue injuries. Cold muscles and tendons are more susceptible to injury.
   
   
3. A 5 minute warm-up increases blood flow to the exercising muscles. A greater level of blood reaching the muscles involved in the activity aids in the delivery of the important fuels (e.g., glucose and free fatty acids) required for energy production.
   
   
4. A 5 minute warm-up increases blood flow to the heart. A greater level of blood delivered to the heart reduces the potential for exercise-induced myocardial ischemia.
   
   
5. Warming up decreases the viscosity of the muscle. Reduced muscle viscosity increases the suppleness of the muscle, thereby enhancing the mechanical efficiency and power of the exercising muscles.
   
   
6. Warming up also causes an early onset of sweating. An early onset of sweating promotes evaporative heat loss and as a result decreases the amount of heat stored by the body. This will help to prevent an individual’s body temperature from rising to dangerously high levels during (more strenuous) exercise.
   
   
7. It also enhances the speed of nerve impulse transmission. As nerve impulses are conducted at a faster rate, neuro-muscular co-ordination tends to improve, resulting in better performance of certain motor tasks.
   
   
8. A warm-up increases the blood saturation of muscles and connective tissue. A higher level of blood reaching the muscles, tendons, and ligaments involved in the activity increases the elasticity of these tissues, resulting in a safer, more effective performance of stretching exercises.
   
   
9. An appropriate warm-up prepares the cardiovascular system for the upcoming (more strenuous) physical activity. Warming up helps to ensure that the cardiovascular system (heart and blood vessels) is given time to adjust to the body’s increased demands for blood and oxygen.
   
   
10. It also prepares the muscular system for the upcoming (more strenuous) physical activity. Warming up provides a transition from a resting state to strenuous exercise, and may reduce the likelihood of delayed muscular soreness.

Happy training!
Dorothy, TriSportsTraining.com