cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal The effects of exercise on the body EFFECTS OF EXERCISE main listing enterquit © Copyright Ali Clarke Design 2003

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Contents – Effect of exercise When you exercise… Exercise & respiratory system Exercise & cardiovascular system Exercise & musculo-skeletal system Preventing overheating Food & drink requirements Smoking & fitness Summary main listing quit

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal When you start to exercise…  The muscles must be kept supplied with oxygen to fuel muscle contractions & allow movement  This involves taking more oxygen into the body by breathing more quickly  The heart also beats faster to pump oxygenated blood around the body more rapidly  Muscle contractions generate a lot of heat, which must be removed to prevent the body from overheating

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal When you train regularly…  Changes occur in your heart, lungs, muscles & bones as you becomes fitter  They allow your body to adapt more quickly to exercise & to make a faster recovery when you finish a training period

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Respiratory  Breathing rate   Air inhaled   Blood flow through Lungs   O 2 collected  CO 2 removed Musculo-skeletal  O 2 demand of muscles   Heat is generated - removed by sweating & flushing of skin  Pulse rate   Blood Pressure   Volume of blood pumped  keeps muscles supplied with O 2 removes waste CO 2 from muscles Cardiovascular Immediate effect of exercise

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Cardiovascular  Heart enlarges slightly  Red blood cells number   Artery walls  elasticity  Muscles, tendons grow  strength   growth of capillaries around muscles  Muscles more efficient at using O 2  Ligaments  strength  Range of movement in joints   Bones  strength Musculo-skeletalRespiratory  Respiratory muscles stronger & more efficient   vital capacity   growth of capillaries around alveoli  Allow you to train harder & longer Effect of regular exercise over time

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & respiratory system  Breathing rate increases  Depth of breathing increases; i.e. volume of each breath increases (maximum possible = vital capacity)  More blood flows through the lungs  These changes allow  Increased amounts of oxygen to be collected to power the exercising muscles  Increased amounts of waste carbon dioxide to be removed

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & respiratory system  With regular exercise, the respiratory muscles (diaphragm + intercostals) become stronger & more efficient at opening up the chest cavity  The vital capacity increases, so more oxygen can be taken in per breath (& more carbon dioxide can be removed)  New capillaries grow around the alveoli, allowing greater oxygenation of the blood (& faster removal of carbon dioxide)  These changes allow you to exercise more vigorously for a longer time

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & cardiovascular system  Heart beats faster; pulse rate increases  Greater volume of blood is pumped per heart beat  Blood pressure rises transiently during exercise  BP drops back to pre-exercise levels when physical activity ceases  Blood is diverted away from the major body organs, except the heart & brain  Blood flow into the muscles is increased  Around 20% of blood volume goes to muscles when body is at rest  This rises to around 90% during vigorous exercise

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal  The body produces more oxygen-carrying red blood cells Exercise & cardiovascular system  With regular exercise, the heart grows slightly larger & its walls become thicker  This allows the heart to hold more blood & to contract with greater force  The artery walls become more elastic & prevent blood pressure rising too far during exercise

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & musculo-skeletal system  The amount of oxygen consumed by the muscles during exercise increases x70 above resting levels  As the muscles work they generate heat, warming the blood  Contracting muscles squeeze the veins & force blood back to the heart

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & musculo-skeletal system  With regular exercise, the muscles (& tendons) get bigger, allowing them to contract with greater strength  Increased numbers of capillaries grow around the muscles, so more blood can reach them with oxygen & nutrients  Muscles become more efficient at using oxygen & can work harder for longer without tiring  The body’s maximum oxygen consumption (VO 2max ) increases

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Exercise & musculo-skeletal system  Regular exercise also strengthens the ligaments around a joint, making the joint stronger & more stable  Stretching movements will also increase the range of movement of a joint  The articular cartilage pads that line synovial joints become thicker, & protect the underlying bones from mechanical stress  Bones become stronger

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Preventing overheating  Repeated muscle contractions release a large amount of heat energy & this must be removed quickly to prevent the body from becoming overheated  Thermal sensors in the brain monitor body temperature; when it rises too high, heat loss mechanisms are put into operation  Heat loss is achieved using two main methods;  Radiation  Evaporation

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal  Heat generated by the muscles is used to warm up the blood  Blood is then shunted through vessels close to the skin surface, which dilate to maximise the volume of blood passing through them  The skin appears flushed & feels hot  Heat radiates from the skin surface into the surrounding colder air, allowing the body to cool down Preventing overheating: radiation

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal  Heat can also be lost by using heat energy to convert liquid into vapour, i.e. evaporation  This is more commonly known as sweating  Sweat is produced by sweat glands present throughout the skin, it contains mostly water plus a few salts  Rising body temperature simulates sweat glands to secrete sweat onto the skin surface, it is then evaporated using body heat energy & helps to cool the body  Excessive sweating can lead to loss of body fluid & salt, causing dehydration & cramping Preventing overheating: evaporation

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal  If the external environment is either hotter than the body or is humid, heat loss by radiation & evaporation will be severely impaired  Heat exhaustion can occur if an athlete overheats & collapses following vigorous exercise; it is often caused by dehydration  Heat stroke is a potentially fatal condition caused by prolonged overheating; it is a medical emergency Overheating

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Food & drink requirements: water  A lot of water can be lost from the body during exercise;  Increased body heat  water lost as sweat  Increased breathing rate  water vapour lost via lungs  Dehydration can result in  Thirst  Headache  Dizziness  Muscle cramps  To avoid dehydration, it is important to take on adequate fluids during exercise

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Food & drink requirements: food  Energy for muscle activity during exercise needs to be available quickly to avoid muscle fatigue  The main source of this energy is the carbohydrate storage molecule glycogen  Body glycogen stores are limited & are depleted during exercise; they can take up to 48 hours to be replenished  Extra carbohydrate must be eaten to replace glycogen stocks during endurance events, such as football or tennis matches, distance running, etc. e.g. bananas, biscuits, jam sandwiches, dextrose tablets

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Smoking & fitness: lung function  Smoking cigarettes damages health & reduces fitness  It impairs lung function by - Reducing alveolar function - Damaging the lining of the airways & increasing mucus production - Increasing the risk of lung infection, emphysema, bronchitis, asthma, & lung cancer  Smoking reduces vital capacity  Smoking reduces aerobic fitness

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Smoking & fitness: cardiac function  Smoking cigarettes damages health & reduces fitness  It impairs cardiac & vascular function by > Smoking reduces cardiac fitness - Damaging the blood supply to the heart muscle - Damaging artery walls - Reducing the amount of oxygen that can be carried in the blood - Increasing the risk of angina, heart attack, & stroke - Increasing the risk of arterial disease - Increasing the risk of blood clots forming in the veins

cardiovascularrespiratorydiet & healtheffect of exercise backcontentsnext musculo-skeletal Summary There are many benefits of regular vigorous exercise… Enhanced stamina & fitness Relief of mental stress & better relaxation Weight control Strengthened bones & joints Improved lung function Reduced risk of heart & vascular diseases Better quality of life! end