Exercise Physiology

1. Exercise Physiology

2. Circulatory System What is the Human Circulatory System ? • The main organ of the circulatory system is the Human Heart. The other main parts of the circulatory system include the Arteries, Arterioles, Capillaries, Venules, Veins and Blood. The Functions of the Circulatory System ? To transport blood around the body. The blood itself also carries numerous other substances which the body requires to function.

3. The Blood Contains….. • The main substance being Oxygen, carried by a protein called haemoglobin, found inside red blood cells. • White blood cells for fighting disease and infection. • Blood contains platelets essential for clotting the blood, which occurs following an injury to stop blood loss. • Blood also carries waste products, such as Carbon Dioxide away from muscles and organs in order to be dispelled by the lungs.

4. Circulatory System How the Circulatory System Works There are three circulatory processes occurring simultaneously within the body. • 1. Systemic Circulation carries blood around the body • 2. Pulmonary Circulation carries blood to the lungs • 3. Coronary Circulation provides the heart with its own supply of blood.

6. Systemic Circulation The heart pumps oxygenated blood out of the left ventricle, through the Aorta (the largest artery in the body). The blood continues back towards the heart, through the veins, into the right atrium. The blood is then transported around the body to the muscles and organs. This Carbon dioxide passes back across the walls of the capillaries, into the blood stream. Here the Oxygen (and other nutrients) passes through the capillaries, into the tissues where it can be used to produce the energy muscles require to contract. Once the nutrients are used during energy production (metabolism) a waste product called Carbon Dioxide is formed.

7. Circulatory System Pulmonary Circulation • Once blood returns to the heart it is then pumped from the right ventricle through the Pulmonary arteries to the lungs, where the waste carbon dioxide can be expelled and more Oxygen collected. The Pulmonary vein carries oxygenated blood back to the left atrium of the heart, where the cycle starts again.

8. Circulatory System

9. Circulatory System • 3. Human blood is colourless, it is the hemoglobin that makes it red. • 4. Red blood cells live for upto 4 months and make approximately 250,000 round trips around the body before returning to the bone marrow, where they were born, to die. Between 2.5 and 3 million red blood cells (erythrocytes) are lost and replaced every second.

10. Circulatory System Did you know!!?? 1. It takes 20 seconds for blood to circulate the entire body. Oxygenated blood leaves the aorta about about 1 mile an hour. 2. The power output of the heart ranges from 1-5 watts per minute. Which is the equivalent to the usage of a 60 watt bulb. It has been said that enough energy is produced a day to drive a truck 20 miles.

11. Circulatory System 5. Due to the heart having its own electrical impulse, it will continue to beat even when removed from the body as long as it has an adequate supply of oxygen. 6. On average, the human body has about 5 liters (almost 9 pints) of blood continually traveling through it by way of the circulatory system. A kitchen tap would need to be turned on all the way for at least 45 years to equal the amount of blood pumped by the heart in an average lifetime.

12. Circulatory System • Terminology • Heart rate is simply the number of heart beats per minute. • Stroke volume is the volume of blood, in milliliters (mL), pumped out of the heart with each beat. • Cardiac output: is the volume of blood pumped by the heart per minute (mL blood/min). Cardiac output is a function of heart rate and stroke volume. Cardiac Output in mL/min = heart rate (beats/min) X stroke volume (mL/beat)

13. Circulatory System • An average person has a resting heart rate of 70 beats/minute and a resting stroke volume of 70 mL/beat. The cardiac output for this person at rest is: • Cardiac Output = 70 (beats/min) X 70 (mL/beat) = 4900 mL/minute. • The total volume of blood in the circulatory system of an average person is about 5 liters (5000 mL). According to our calculations, the entire volume of blood within the circulatory sytem is pumped by the heart each minute (at rest). During vigorous exercise, the cardiac output can increase up to 7 fold (35 liters/minute)

14. Respiratory System Function of the Respiratory System • The function of the human respiratory system is to transport air into the lungs and to facilitate the diffusion of Oxygen into the blood stream. Its also receives waste Carbon Dioxide from the blood and exhales it.

15. Respiratory System What is the Respiratory System? • The respiratory system consists of the following parts, divided into the upper and lower respiratory tracts:

16. Respiratory System Parts of the Upper Respiratory Tract Mouth, nose & nasal cavity: The function of this part of the system is to warm, filter and moisten the incoming air Pharynx: Here the throat divides into the trachea (wind pipe) and oesophagus (food pipe). There is also a small flap of cartilage called the epiglottis which prevents food from entering the trachea Larynx: This is also known as the voice box as it is where sound is generated. It also helps protect the trachea by producing a strong cough reflex if any solid objects pass the epiglottis.

17. Respiratory System Parts of the Lower Respiratory Tract • Trachea: Also known as the windpipe this is the tube which carries air from the throat into the lungs. It ranges from 20-25mm in diameter and 10-16cm in length. • Bronchi: The trachea divides into two tubes called bronchi, one entering the left and one entering the right lung. The left bronchi is narrower, longer and more horizontal than the right.

18. Respiratory System Bronchioles: Tertiary bronchi continue to divide and become bronchioles, very narrow tubes, less than 1 millimeter in diameter. Alveoli: Individual hollow cavities contained within alveolar sacs (or ducts). Alveoli have very thin walls which permit the exchange of gases Oxygen and Carbon Dioxide. They are surrounded by a network of capillaries, into which the inspired gases pass. There are approximately 3 million alveoli within an average adult lung. Diaphragm: The diaphragm is a broad band of muscle which sits underneath the lungs, attaching to the lower ribs, sternum and lumbar spine and forming the base of the thoracic cavity.

19. Respiratory System Terminology • Respiratory Volumes: is the amount of air inhaled, exhaled and stored within the lungs at any given time • Tidal Volume: the amount of air which enters the lungs during normal inhalation at rest. The average tidal volume is 500ml. The same amount leaves the lungs during exhalation. • Total Lung Capacity: This is the total amount of air the lungs can hold. The average total lung capacity is 6000ml, although this varies with age, height, sex and health.

20. Respiratory System

21. ENERGY SYSTEMS Muscle Contraction causes Movement, but requires ENERGY to do so!!!

22. The ATP Molecule • Adenosine Tri-phosphate (ATP) P Adenosine P P b. The breakdown of ATP into ADP + P: P Adenosine P P Energy Energy for cellular function to contract working muscle

23. ATP Production at Rest • ATP replenish with the use of Oxygen (Aerobic) • Uses 75% Fats (lipids) and 25% CHO (glycogen) • Wastes products are expired and breathed out

24. The ATP Molecule • Unfortunately there is only enough ATP in the muscles to last for 2 seconds. • The body has 3 other systems to replenish ATP to ensure we can keep exercising.

25. ATP Production during Exercise • 3 Systems used to replenish ATP • ATP-CP System • Anaerobic (Lactic Acid) Glycolysis • Aerobic Glycolysis

26. The ATP-CP System • Duration: 1-15 seconds • When: Sudden increase in intensity (whilst oxygen supply catches up), or short intense movements • This system breaks down stored Creatine Phosphate (CP) in the muscle; it requires no oxygen (anaerobic) • Limitations:by amount of CP the body can store. • What sports predominantly use this system?

27. ATP-CP Energy System • Replenishes ATP rapidly by breaking down Creatine Phosphate releasing energy to reform ATP • Short duration (<10 secs) • Active at the beginning of all forms of activities • Especially important in high intensity exercises like weight lifting that require short bursts of energy. • Only a small quantity of PC can be stored. Athletes do try to load up with supplements

28. The Anaerobic Lactic System • Duration:Up to 3 minutes • When: Sudden increase in intensity (whilst oxygen supply catches up), or when excising above AT (anaerobic Threshold) • Provides energy for moderate to high intensity exercise. The system uses energy from the breakdown of carbohydrates (glucose) and requires no oxygen. • Limitations: Production of lactic acid. • What Sports predominantly use this system?

29. Anaerobic (Lactic Acid) Glycolysis • Breakdown of carbohydrates (glycolysis) for fuel when without oxygen eg beginning of exercise or high intensity workout >85% of HRmax • Results in formation of lactic acid, which causes muscle fatigue • Last for 10 seconds to 2 minutes • 1 molecule- 3 ATP molecule

30. Aerobic System • Duration: Unlimited • Predominant energy supplier for low to moderate intensity exercise <85% HR MAX • The system breaks down both carbohydrates and fatsfor energy and requires oxygen (aerobic). • What Sports predominantly use this system?

31. Aerobic Glycolysis • Replenishes ATP with the use of oxygen • System works at rest and during very low intensity exercise • This form of energy primarily utilizes fats (75%) and carbohydrates (25%) as fuel sources, but as intensity is increased there is a switch from fats (25%) to carbohydrates (75%)

32. Energy System Interplay • The interplay of energy systems refers to the dominant energy system at any given time during an event. • All energy systems make ATP from the start of physical activity. However, one is more dominant than the others at particular times, depending on the intensity & duration of the activity.

33. Energy Transfer Systems and Exercise 100% % Capacity of Energy System Anaerobic Glycolysis Aerobic Energy System ATP - CP 10 sec 30 sec 2 min 5 min +

34. Energy Systems • Describe how the three energy systems interconnect when a person completes a 3km run. • Anaerobic (ATP-CP) system is used to start the race. As the person continues to ‘take off’ at speed, lactic acid begins to build up in the muscle. After 2-3 minutes the aerobic system kicks in and begins to remove lactate from the muscle and fuel work needed for the remainder of the run.

35. Energy Systems • Give two examples of activities that would be fuelled primarily by each energy system: • Anaerobic (ATP-CP) system- Jumping up to contest a jump ball in basketball. • Lactic Acid System- Playing a game of touch or basketball as they both require repeated bouts of high intensity work. • Aerobic System- Multi-sport race marathon

36. Short Term Effects of Exercise • When we begin to exercise the body has to respond to the change in activity level

37. Short Term Effects of Exercise Circulatory System • The release of adrenaline (often before exercise even begins) causes the heart rate to rise • Increase in Cardiac Output • Increases in Lactic Acid (produced during the early anaerobic phase of exercise), Carbon Dioxide (due to increased rates of energy production) and temperature all act as stimuli to the cardiac control centre which responds by further increasing the heart rate • Oxygen levels within the blood decrease which causes increased diffusion at the lungs • Blood pressure increases, thus increasing flow rate and the speed of delivery of O2 and nutrients to the working muscles

38. Short Term Effects of Exercise Respiratory System • Changes in the concentration of CO2 and O2 in the blood are detected by the respiratory centre which increases the rate of breathing • The intercostal muscles, diaphragm and other muscle which aid the expansion of the thoracic cavity work harder to further increase the expansion during inhalation, to draw in more air.

39. Short Term Effects of Exercise Muscles • The higher rate of muscle contraction depletes energy stores and so stimulates a higher rate of energy metabolim. • The bodys energy stores are slowly depleted • Myoglobin releases its stored Oxygen to use in aerobic respiration. O2 can now be diffused into the muscle from the capillaries more quickly due to the decreased O2 concentration in the muscle

40. Short Term Effects of Exercise When you begin to exercise your body must immediately adjust to the change in activity level. Energy production must increase to meet demand with changes to the predominant energy system and fuel source occuring throughout the exercise in order to maintain the required level of performance.

41. Short Term Effects of Exercise Responses to Anaerobic Exercise • In order to immediately meet the sudden higher energy demand, stored ATP is the first energy source. This lasts for approximately 2 seconds. • When stored ATP is used up the ATP-PC system kicks in but it can only last 8-10 seconds before PC stores are depleted. • The lactic acid system (Anaerobic glycolysis) must then take over as the predominant source of energy production. High intensity (but sub-maximal) exercise can last for between 3 and 5 minutes using this system • If the exercise continues at a high intensity, and Oxygen is not available at a fast enough it interferes with muscular function. This is called the Lactate threshold.

42. Short Term Effects of Exercise Responses to Aerobic Exercise • Due to the necessity of Oxygen being present for aerobic metabolism, the first few minutes of low to moderate intensity exercise are powered by anaerobic metabolism. • Continued low to moderate intensity exercise is then fuelled by carbohydrate and fat stores using aerobic metabolism.

43. Short Term Effects of Exercise Responses to Aerobic Exercise (Points of Interest) • The intensity and duration of exercise determines which fuel source is used. Fat metabolism is a slow process and so can only be used as fuel for exercise at less than 60% VO2 max. • Carbohydrate is a much faster fuel source and so can be used for exercise up to 80% (in trained individuals). • Carbohydrate stores within the muscle and liver can fuel exercise for up to 80 minutes. As carbohydrate stores get lower, the body has to rely more and more on fat stores. • The intensity of exercise which can be maintained drops as fat cannot supply the required amount of energy.

44. Long Term Effects of Exercise • Regular exercise results in adaptations to the circulatory, respiratory and muscular systems in order to help them perform better under additional stress. Here are the changes which must take place within the muscles, respiratory system and circulatory system:

45. Long Term Effects of Exercise • Circulatory System • The cardiac muscle surrounding the heart gets bigger, resulting in thicker, stronger walls. • This allows an increase in heart volume. The more blood pumped around the body per minute, the faster Oxygen is delivered to the working muscles. • The number of red blood cells increases, improving the bodies ability to transport Oxygen to the muscles for aerobic energy production.

46. Long Term Effects of Exercise • Circulatory System • The density of the capillary beds in the muscles and surrounding the heart and lungs increases as more branches develop. This allows more efficient gaseous exchange of Oxygen and Carbon Dioxide. • The resting heart rate decreases in trained individuals due to the more efficient circulatory system. • The accumulation of lactic acid is much lower during high-levels activity, due to the circulatory system providing more Oxygen and removing waste products faster.

47. Long Term Effects of Exercise • Respiratory System and Exercise • The respiratory muscles (Diaphragm/intercostals) increase in strength. • This results in larger respiratory volumes, which allows more Oxygen to be diffused into the blood flow • An increase in the number and diameter of capillaries surrounding the alveoli leads to an increase in the efficiency of gaseous exchange.

48. Long Term Effects of Exercise Muscle • Increased numbers of mitochondria (the cells powerhouse) means an increase in the rate of energy production. • The muscles, bones and ligaments become stronger to cope with the additional stresses and impact put through them. • The amount of myoglobin within skeletal muscle increases, which allows more Oxygen to be stored within the muscle, and transported to the mitochondria. • Muscles are capable of storing a larger amount of glycogen for energy. • Enzymes involved in energy production become more concentrated and efficient to aid the speed of metabolism.

49. Mitochondria • Mitochondria are the cell's power producers. They convert energy into forms that are usable by the cell.

50. Training for Volleyball • If you were to start a 6 month training programme for Volleyball what methods of training might you use? • What effect would these have?