Utilisation

Carbohydrates, proteins and fats are utilised by the body for a large range of functions.

Uses Of Carbohydrates

• Energy – blood sugar, muscle, brain, liver (proteins spring).
• Formation of liver and muscle glycogen (short-term energy store).
• "Fat primer"(regulates lipid metabolism).
• Fibrous components (dietary fibre) acids, GI track function.
• Futile cycling/heat production.

Uses Of Protein

• Tissue growth, repair and regeneration.
• Hormonal and enzyme protection.
• Acid-base balance.
• Structure – collagen and elastin (hair, nails, tendons, skin, ligaments) cell membrane, internal cellular material.
• Energy (small to moderate contribution).

Use Of Fat

• Energy.
• Adipose tissue – energy store, organ protection, insulation.
• Vehicle for fat soluble vitamins.
• Cell membrane structure (phospholipids and chol).
• Cholesterol transport (by LDL and HDL)
• production of prostaglandins (intracellular regulator of metabolism formed from EFA's).

The trainer should be primarily concerned with the role of microelectronics in energy metabolism as this has the most obvious crossover to exercise.

Energy Requirements For Exercise.

• The total energy requirements and the contributions from the various macro nutrients, for exercise is dependent on the intensity and duration of the exercise. Physical activity may account for anywhere between 0 to 30% of total energy expenditure depending on an individual's circumstances (example bedridden, tri-athletes in training).
• During short duration, intense exercises carbohydrates in the form of muscle glycogen (> 60%) and blood glucose (30 – 40%) are the prime energy source.
• In the early minutes of moderate and prolonged exercise almost all the energy is supplied from glycogen stored in the active muscles. During the subsequent 20 minutes (approx), the liver and muscles provide approximately 40 – 50% of energy, with the remainder provided primarily from free fatty acids in the blood. As the duration of the activity continues and glycogen stores become reduced, more energy is supplied from fat metabolism. Amino acids play and increasing role in the production of glucose (gluconeogenesis) as glycogen stores become depleted, eventually supplying as much as 10 – 15% of total exercise. Energy requirements.