3.2.3.3 - Energy use, diet, nutrition and hydration

1. 3.2.3.3 - Energy use, diet, nutrition and hydration Learning objectives To understand the role and importance of macronutrients and micronutrients. To describe how the body gets energy from nutrients and the role of these within the body. To explain the importance of hydration for physical activity.

2. Energy use Watch me How does the nutritional requirements change for different athletes?

3. Energy use Energy is measured in calories (Kcal) and is provided through the food we eat. The average male requires 2500 Kcal per day and females 2000. Think. Pair. Share – For what reasons might the average calorie intake change?

4. Energy use The following factors can alter the number of calories required by an individual. • Height • Gender • Energy expenditure (exercise) • Age Some athletes need to maintain their weight carefully and as such will pay close attention to their dietary intake. i.e. boxers and jockeys

5. Energy, diet and hydration The energy requirements for physical activity can differ dependant on many factors. • Exercise/intensity level - The higher the exercise intensity the more energy needed. • Age – Younger individuals need more energy than older adults. • Gender – Women tend to need less energy intake than men.

6. Energy, diet and hydration A balanced diet is essential for health as well as to cope with the physical demands of sport. • A balanced diet is needed as: • Unused energy is stored as fat which can cause obesity. • Energy stores are ready for exercise. • Nutrients are needed for energy, growth and hydration. Think. Pair. Share – What should be included in a balanced diet?

7. Nutrition A balanced diet involves consuming each element in proportion.

8. Nutrition 1. Carbohydrates – this macronutrient is the ‘fuel’ that provide us with energy to sustain performance. Glucose in the form of Glycogen is broken down from carbohydrate to provide energy.

9. Nutrition Other sources of carbohydrate:

10. Nutrition 2. Fats – These are also used for energy, but only when stores of carbohydrate run low. Fat provides very slowly released energy. This is important for endurance activities. The longer you work the more fat is used. The fitter you are the more easily your body uses up stores of fat

11. Nutrition Other sources of fats:

12. Nutrition 3. Protein – Protein is an essential nutrient that promotes growth and repair of muscles. Proteins are also used to generate energy only when the body has exhausted its stores of carbohydrates and fats. Proteins are especially important for sportspeople who need to build up large, powerful muscles. Performers in sports like weightlifting, rugby and sprinting need a high protein diets.

13. Nutrition Other sources of protein:

14. Nutrition Proteins are also needed by performers who are recovering from injury in order to repair damaged tissue.

15. Nutrition 4. Minerals – Your body needs minerals to help it function. In particular minerals increase the efficiency of carrying oxygen to muscles. • Minerals can be found in: • Calcium in milk • Iron in meat • Minerals are only needed in small quantities but are vital for the body.

16. Nutrition 5. Vitamins – these generally contribute to the general health of an athlete. • Vitamins are needed to: • Resisting infection and disease • Regulate chemical reactions in the body.

17. Water balance - hydration Watch me What are the effects of dehydration on athletes?

18. Water balance - hydration It is essential to keep taking a small amount of fluid at regular intervals during exercises to enable the body to function properly. Symptoms of dehydration are tiredness, lack of concentration and headaches. Performers exercising in hot climates may need to drink up to 2 litres of water per hour!

19. Water balance - hydration • Dehydration in the body can cause: • Blood thickening which slows blood flow around the body. • Increased heart rate/irregular heart rhythm. • Increased body temperature. • Slower reaction time/poor decision making. • Increased muscle cramps and fatigue.

20. Apply it! What has stuck with you?

21. Practice it! Exam questions 1. Sports performers make sure they eat a balanced diet. Briefly explain the importance of carbohydrates and protein to an elite sports performer. (i) Carbohydrates (2) ........................................................................................................................................................................................................................ (ii) Protein (2) ........................................................................................................................................................................................................................

22. Practice it! Exam questions 2. Summarise the effects of dehydration on the body. (3)

23. Practice it! Exam questions 3. A group of amateur runners are attempting their first marathon. Some of the runners take advantage of the drinks offered to them during the race whilst others do not. Evaluate the actions of the runners who do not take advantage of the drinks available. (3)

24. Practice it! • Marks Scheme: • (i) A linked explanation, e.g. Carbohydrates provide energy (1) so quality of performance remains high/optimum performance (1) Carbohydrates provide energy (1) so they can last longer in their game/race/event. Carbohydrates provide energy (1) so they can maintain/continue activity level in game/race/event without tiring. • (ii) Protein is used for growth/ increased muscle mass/bigger muscles (1) so stronger/powerful/faster for their event (1) Repair of tissue/muscle (1) to recover from injury/quicker recovery (1) • 2. Increased heart rate (beats per minute), increased lactate acid in muscles (increased blood acidity), increased body temperature, decreased strength.

25. Practice it! Marks Scheme: 3. More likely to suffer from dehydration, which has a negative effect on running performance (1) More likely to suffer from increases in heart rate so the heart has to work harder to supply oxygen to the muscles when running (1) Reduction in blood flow to working muscles / thicker (viscous blood) which means less oxygen to the muscles and it is harder to remove waste products – slows recovery so harder to continue in the marathon (1) Increase in body temperature so body could overheat during the race and become faint / pass out and cannot carry on (1) Muscle fatigue more likely which could cause cramps so cannot carry on (1)