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The Effects of Exercise

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Presentation on theme: "The Effects of Exercise"— Presentation transcript:

1 The Effects of Exercise
KS4 Physical Education The Effects of Exercise These icons indicate that teacher’s notes or useful web addresses are available in the Notes Page. This icon indicates that the slide contains activities created in Flash. These activities are not editable. For more detailed instructions, see the Getting Started presentation. 1 of 30 © Boardworks Ltd 2006

2 Learning objectives Learning objectives
What we will learn in this presentation: The immediate effects of exercise on the respiratory system The immediate effects of exercise on the circulatory system How levels of lactic acid, water and heat are affected by exercise How the body recovers from exercise Recovery rates The long term effects of exercise on the heart, lungs, skeleton and muscles How different components of fitness can be tested. Learning objectives 2 of 30 © Boardworks Ltd 2006

3 The immediate effects of exercise

4 Immediate effects on the respiratory system
Exercise causes the muscles to use more oxygen. This means that the lungs must work harder and faster to keep the body supplied with oxygen and also to exhale the carbon dioxide that is produced. This is why exercise makes you out-of-breath. Breathing rate increases from around 18 breaths per minute to up to 80! The amount of air inhaled and exhaled in each breath also increases from around 0.5 litres to up to 4.5 litres. During aerobic exercise, the lungs are able to work fast enough to supply the muscles with oxygen. During anaerobic exercise, the lungs can’t supply enough oxygen. Once the exercise is over, breathing remains fast to repay the ‘oxygen debt’.

5 Immediate effects on the circulatory system
During exercise, the circulatory system’s most important function is transportation. The heart and blood vessels work to transport the oxygen from the lungs to the muscles where it is needed. Glucose and other substances needed by the muscles are transported in the blood too. The by-products of respiration, including carbon dioxide and lactic acid, are also carried away from the muscles. carbon dioxide glucose + oxygen energy + + water glucose energy + lactic acid If these by-products build up in the muscles, they can cause them to stop working.

6 Immediate effects on the circulatory system
In response to exercise, the heart beats not only faster, but stronger. Heart rate increases from around 70 bpm to up to 200 bpm. Stroke volume (the volume of blood pumped per beat) increases from around 50 ml to around 120 ml. In highly trained athletes, stroke volume can reach 200 ml. The arteries respond to the body’s increased demands by widening slightly to allow more blood to pass through them. Blood is also diverted away from systems that are not involved in the activity, for example, the digestive system. Write a paragraph explaining how the roles of the heart and lungs in supporting exercise are connected.

7 The immediate effects: lactic acid
Lactic acid is produced during anaerobic respiration. This happens when there is not enough oxygen for normal aerobic respiration to take place. glucose energy + lactic acid Lactic acid is a mild toxin. It is responsible for the pain you feel in your muscles when they get tired. When too much of it builds up in a muscle, it can prevent the muscle contracting. At this point, the performer’s muscles will cramp and they will be forced to stop.

8 The immediate effects: heat loss
The body has two main ways of getting rid of the extra heat produced by muscles during exercise. Vasodilation The capillaries close to the surface of the skin dilate, allowing more blood to flow into them. Because the blood is closer to the skin, more heat is lost to the environment. Sweating Sweat glands in the skin excrete sweat – a mixture of water, salts and urea. As the sweat evaporates, it takes heat away with it. Sweat image © 2006 Jupiterimages Corporation

9 The immediate effects: water loss
When you sweat, water is lost from the body. Water is vital to maintaining proper body functions. The body produces less urine to compensate, but during prolonged exercise or in hot weather, this is often not enough. Extra water must also be consumed. The body does not only lose water – it also loses important salts called electrolytes. These are necessary in many areas of the body, including the nervous system. Salts can be replaced during exercise by drinking isotonic drinks, or eating foods rich in these minerals. Extreme cases of salt depletion may occur during ultra-long distance activities in very hot and humid climates. Strenuous hiking in tropical climates and dessert marathons are examples of high-risk activities. Severe salt depletion can lead to cramps, fainting and, in extreme cases, death.

10 Immediate effects of exercise

11 Recovery rates Your recovery rate is how quickly your body returns to normal following a period of exercise. Recovery rate is a good indicator of fitness. The quicker you recover, the fitter you are. As you recover from exercise, changes happen in the following areas: Heart rate Lactic acid levels in the blood Pasta image © 2006 Jupiterimages Corporation Glycogen stores Muscles

12 Heart rate

13 Muscles Strenuous exercise can cause slight damage to the muscle fibres. It is actually through this process of damage and repair that muscles become stronger. As you would expect, your body needs time to repair the damage done to muscles during exercise or training. After exercise, we sometimes experience stiffness or soreness for a period of time until our muscles have fully recovered. This soreness can also be caused by lactic acid remaining in the muscles.

14 Recovery time When you plan your training, ensure that you allow your body enough time to recover between training sessions. It you train hard every day, try and alternate between heavy sessions and light sessions to aid recovery Always ensure that you have the appropriate rest periods or you run the risk of injury through overtraining. Image © 2006 Jupiterimages Corporation

15 Recovery

16 The long term effect of exercise
As you would expect, training causes the body to adapt and grow stronger. The following areas are particularly affected: the heart the lungs the skeleton the muscles.

17 The long term effect of exercise – the heart
Aerobic exercise strengthens the heart. The heart becomes bigger. The walls become thicker and stronger. The stroke volume increases. The result is that the heart becomes a more efficient pump. Your resting heart rate gets slower as you get fitter, because the heart needs fewer beats to pump blood round the body. Training also results in new capillaries growing to improve the supply of blood to the muscles.

18 The long term effect of exercise – the lungs
Training makes the lungs more effective at supplying the body with oxygen. New capillaries grow around the alveoli, making gas exchange more efficient. The muscles involved in breathing in and out become stronger and can work for longer. Vital capacity (the maximum amount of air that can be inhaled in one breath) increases.

19 The long term effect of exercise – the skeleton
Exercise has been shown to increase bone density and strength. Stronger, denser bones are better at carrying weight and more resistant to injury. The increase in bone density is specific to the activity – walking will strengthen your leg bones, but not your arm bones. Both aerobic exercise and weight training are effective in increasing bone strength, but the activity must be weight-bearing.

20 The long term effect of exercise – the muscles
Training obviously has a large effect on the muscles. The other effects will depend on the type of training. New capillaries grow in and around the muscles to supply them with blood. Weight and power training increases the strength of muscles. The number of fast twitch fibres increase. Muscles increase in size. Endurance training makes muscles able to work for longer. The number of slow twitch fibres increase. © EMPICS Ltd © EMPICS Ltd

21 The effects of exercise


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