The effects of acute/ Short term exercise on the respiratory system Respiratory response: increase in breathing rate (neural and chemical control); increased tidal volume. Short Term - The mechanics of breathing • When we start to exercise, such as during a warm up the mechanics of breathing alter considerably • This can help to explain how we breathe in faster and deeper during exercise, and therefore help you to answer part of the first two questions. • This increases the amount of air that reaches the alveoli in the lungs. Mechanics of breathing - Inspiration • During exercise, – More muscles are involved • The sternocleidomasoid, sclanes and pectoralis major are now involved as well as the diaphragm and external intercostal muscles – This means that the sternum lifts further and faster than it does at rest – Muscles work harder • The external intercostals and diaphragm in particular flattens with more force Mechanics of breathing - Expiration • During exercise – Becomes an active process • Internal intercostal muscles now contract – They pull the rib cage down • More muscles are involved – Rectus abdominus/obliques now contract as well • The diaphragm pushes up harder into the thoracic cage. Changes to lung volume • Give an example based on a football player that is working at maximum intensity – Eg. He has just sprinted flat out to get on to a through ball. – What changes would you expect to see in the different lung volumes from rest to this maximal exertion. • There is an example on the next slide that will help you with this, and allow you to illustrate your answer Respiratory volumes • Tidal Volume – The volume of air inspired or expired per breath (Approx 500ml at rest) • Inspiratory Reserve Volume – The amount of space that is available to draw in more air • Eg; Breathe in normally, then breathe in more. This extra capacity is your IRV • Expiratory Reserve Volume – The amount of space that is available to breathe out, once you have exhaled normally • Eg: Breathe out normally, then force out more air. This is your ERV. Respiratory volumes • • Residual Volume – Breathe out as much as • possible • There is always some air left in your lungs • This is your RV (Approx 1200ml) Vital Capacity – Breathe in as much as you can, and then force as much air out of your lungs as possible. • This is your IRV+ERV+TV, and is your Vital Capacity Total Lung Capacity – Take in as much breath as possible – This is your total lung capacity – ERV+IRV+TV +RV (Approx 6000ml) Lung volumes example Lung Volume Resting Volume Change due to exercise Tidal Volume (X) 500ml per breath Increases up to 4 times Frequency 12-15 Increases up to 60 Minute Ventilation (VE) 6l/min Inspiratory reserve Volume 3000ml Up to 175l/min in large aerobically trained athletes Decreases Expiratory reserve Volume 1200ml Decreases Vital Capacity 4700ml Slight decrease Residual Volume 1200ml Slight decrease Total Lung capacity 5900ml Slight decrease Short term effects – why does our rate of breathing get faster and deeper • Breathing is controlled by the Respiratory control centre – Located in the medulla oblongata • Split into inspiratory and expiratory centres • Controls the respiratory muscles that initiate breathing • They are under involuntary neural control – We don’t normally consciously control our breathing rate During exercise • A number of things stimulate the Respiratory Control Centre to work harder • When our muscles use Oxygen, we produce Carbon Dioxide. – Chemeroceptors located in the veins • send information to the RCC • Detect the increased content of Carbon Dioxide in the blood and the decrease in Oxygen – This stimulates the RCC to increase the rate and depth of breathing. Long term effects – Vital Capacity – After 6 weeks of training, your respiratory muscles will become stronger. • This means that you will be able to use your external intercostal muscles and sternocleidomastoid muscles to breathe in deeper • And your internal intercostal muscles, abdominals and obliques to push more air out of the body – This will result in an increase in vital capacity • Maximum amount of air that you can produce after you breathe out as hard as you can P1/P2/M1 Assessment Ideas… • • • • Leaflet Information Brochure Power Point Spider Diagrams for each system -Remember… If you are going for Merit: you only explain in further detail (using examples, sports and wider reading) the musculoskeletal, CV and Respiratory systems. Some added help, questions for you to answer in your work… • What are the acute effects of exercise on the cardiovascular and respiratory systems • What causes these responses? What happens during steady state and maximal exercise • What are the acute effects of exercise on the skeletal and muscular systems • What causes these responses? What happens during steady state and maximal exercise • What are the acute effects of exercise on the energy systems • What causes these responses, how do the energy systems work together, What happens during exercise of different intensities and maximal exercise.