1. Sports Science 5.9 Sports drinks and sports diets

2. Learning objectives Understand how and why isotonic sports drinks are produced Understand how and why isotonic sports drinks are produced The differences between a normal balanced diet and an athletes diet The differences between a normal balanced diet and an athletes diet

3. Dehydration Dehydration – removal of water from an object Dehydration – removal of water from an object Water not the best Water not the best Quenches thirst before water is replaced Quenches thirst before water is replaced Encourages kidneys to produce urine Encourages kidneys to produce urine Body is 50-80 % water – does function properly if water is lacking Body is 50-80 % water – does function properly if water is lacking Men – 2.9 litres Men – 2.9 litres Women – 2.2 litres Women – 2.2 litres

4. Sports drinks Designed to supply an athlete with what’s needed Designed to supply an athlete with what’s needed Glucose, water, electrolytes (ions), flavourings Glucose, water, electrolytes (ions), flavourings Rehydrate and boost energy Rehydrate and boost energy Contents of drink depends on sport Contents of drink depends on sport Sports nutritionist Sports nutritionist Maximises performance Maximises performance

5. What’s important Taste Taste Glucose content – instant energy Glucose content – instant energy Stomach emptying – high glucose, slower it enters intestine Stomach emptying – high glucose, slower it enters intestine Absorption – higher glucose and ions encourage uptake Absorption – higher glucose and ions encourage uptake Urine production – salts reduce urine output. Electrolytes conduct electricity. Urine production – salts reduce urine output. Electrolytes conduct electricity. Isotonic – Iso- means ‘same’ – same concentration as in blood Isotonic – Iso- means ‘same’ – same concentration as in blood

6. Producing isotonic drinks

7. Carb/glycogen loading Carbohydrates break down into glucose Carbohydrates break down into glucose Stored as glycogen Stored as glycogen Only enough for 90 minutes exercise Only enough for 90 minutes exercise ‘Hit the wall’ ‘Hit the wall’ Diet can increase glycogen and compensate for loss Diet can increase glycogen and compensate for loss Plan before a sporting event Plan before a sporting event

8. Before the big day Days before event DietExercise 7-5 Low carbohydrate diet Strenuous exercise 4-2 Increase carbohydrate Reduce exercise 1 High carbohydrate diet – ‘Pasta party’ Complete rest

9. Protein If carbohydrate are insufficient to meet energy needs – protein broken down If carbohydrate are insufficient to meet energy needs – protein broken down Eating more protein does not increase muscle mass Eating more protein does not increase muscle mass Muscle mass increases due to exercise when sufficient protein is available Muscle mass increases due to exercise when sufficient protein is available Sprinters train to gain muscle Sprinters train to gain muscle

10. High-protein diet Breakfast: Bacon and eggs Breakfast: Bacon and eggs Lunch: Salad and double cheeseburger (no bread) Lunch: Salad and double cheeseburger (no bread) Dinner: Big juicy steak and salad topped with cheese dressing Dinner: Big juicy steak and salad topped with cheese dressing High protein/low carb – can cause health problems High protein/low carb – can cause health problems

11. Key points Isotonic sports drink contain water, glucose and electrolytes Isotonic sports drink contain water, glucose and electrolytes All athletes need a carbohydrate diet that provides energy All athletes need a carbohydrate diet that provides energy Power athletes such as sprinters have a high protein diet to build muscle mass Power athletes such as sprinters have a high protein diet to build muscle mass