170 likes | 380 Views
PHYSIOLOGICAL RESPONSES TO PHYSICAL ACTIVITY vce physical education unit 3. FOODS, FUELS AND ENERGY SYSTEMS. FOOD FUELS. Our food intake consists of three basic nutrients: CARBOHYDRATES FAT PROTEIN. CARBOHYDRATES.
E N D
PHYSIOLOGICAL RESPONSES TO PHYSICAL ACTIVITYvce physical educationunit 3. FOODS, FUELS AND ENERGY SYSTEMS
FOOD FUELS Our food intake consists of three basic nutrients: • CARBOHYDRATES • FAT • PROTEIN
CARBOHYDRATES • CARBOHYDRATES ARE THE BODY’S PREFERRED FUEL SOURCE, ESPECIALLY DURING EXERCISE • SUGARS AND STARCHES SOURCES: FRUIT, CEREAL, BREAD,PASTA, VEGETABLES. .
FAT • ACTS AS A CONCENTRATED FUEL STORAGE IN MUSCLES. • IT IS THE BODY’S MAIN SOURCE OF FUEL AT REST AND DURING PROLONGED SUBMAXIMAL EXERCISE. • SOURCES: BUTTER, CHEESE, OIL, NUTS, FATTY MEATS.
PROTEIN • PROTEINS MAKE A NEGLIGABLE CONTRIBUTION TO ENERGY PRODUCTION DURING EXERCISE. • MAINLY USED FOR GROWTH AND REPAIR. • SOURCES: MEAT, FISH, POULTRY, LEGUMES, EGGS, GRAINS
How does food help us move? • ALL FOODS ARE BROKEN DOWN AND STORED AS CHEMICAL ENERGY. • THIS MUST BE THEN BE CONVERTED TO MECHANICAL ENERGY TO ALLOW MUSCULAR CONTRACTIONS AND MOVEMENT TO OCCUR.
ATP – ADENOSINE TRIPHOSPHATE • MOLECULES OF ATP CONSIST OF ATOMS HELD TOGETHER BY BONDS THAT STORE ENERGY. • CHEMICAL ENERGY IS PRODUCED WHEN ATP IS BROKEN DOWN. • ENERGY IS THEN RELEASED TO FUEL ALL PROCESSES WITHIN THE BODY. • ONLY A VERY SMALL AMOUNT OF ATP EXISTS AT THE MUSCLES.
ATP ADP + P+P+PI • ADENOSINE P P P ENERGY FOR MOVEMENT P P PI ADENOSINE
THREE ENERGY SYSTEMS • ANAEROBIC SYSTEMS-WITHOUT OXYGEN ATP-PC / ALACTACID SYSTEM LACTIC ACID /ANAEROBIC GLYCOLYSIS • AEROBIC SYSTEM – WITH OXYGEN AEROBIC SYSTEM / AEROBIC GLYCOLYSIS
FOOD FUELS AT REST • FAT AND GLYCOGEN ARE THE PREFERRED FUELS UNDER RESTING CONDITIONS. • RESTING CONDITIONS SUPPLY THE HEART, LUNGS AND BLOOD VESSELS WITH SUFFICIENT OXYGEN, AND THEREFORE ATP, TO MEET THE ENERGY REQUIREMENTS.
FOOD FUELS DURING EXERCISE • THE INTENSITY AND DURATION OF EXERCISE DETERMINES WHICH ENERGY SYSTEM IS THE MAJOR CONTRIBUTOR GOR ENERGY. • HIGH INTENSITY EXERCISE / ANAEROBIC EXERCISE – FOOD FUEL IS CARBOHYDRATES • LOW INTENSITY EXERCISE / AEROBIC EXERCISE – • CARBOHYDRATES THEN FAT. • PROTEIN AS A FUEL IS ONLY USED IN EXTREME ULTRA LONG DISTANCE EVENTS, SUCH AS MARATHONS/IRONMAN TRIATHLONS.
GLYCEMIC INDEX (GI) THE GLYCEMIC INDEX IS A WAY OF CLASSIFYINNG CARBOHYDRATES BY THEIR IMMEDIATE EFFECT ON BLOOD GLUCOSE LEVELS.
GLYCEMIC INDEX • HIGH GLYCEMIC INDEX - Carbohydrates are rapidly absorbed into the blood stream and have an immediate effect on blood glucose levels. • LOW GLYCEMIC INDEX – Carbohydrates take a lot longer to break down and be absorbed into the bloodstream, thus having a slower, more sustained effect on blood glucose levels.
EXAMPLES OF GI VALUES • A low GI value is 55 or less (bananas, grain bread, lentils, apples, porridge, spaghetti) • A medium GI value is 56-69 (white bread, mars bar, rye bread, ice cream) • A high GI value is 70 or more (glucose, mashed potato, white rice, doughnut, cornflakes)
Glycemic index and exercise • BEFORE EXERCISE – Low GI carbohydrates should be consumed 45-60 minutes before exercise. These are recommended as they sustain blood glucose levels minimising any increases in insulin release.