CARDIORESPIRATORY ENDURANCE Chapter 3 Cardiorespiratory Endurance • The ability of the body to perform prolonged, large muscle, dynamic exercise at moderate-to-high levels of intensity. • This is the most important health related component of physical fitness. • A healthy heart is essential to high levels of fitness and wellness, as well as to a long and healthy life! The Heart ~ A very muscular organ ~ Four chambered, fist-sized muscle. ~ Weighs between 8 and 10 oz. ~ Lies slightly to the left of center in the chest. ~ Each day, will beat 100,000 times (at rest). ~ Purpose is to pump oxygen-poor blood to the lungs, and oxygen-rich blood to the rest of the body. ~ At rest, about 5 qts. of blood are circulated each minute. ~ With exercise about 20 or more qts. of blood are pumped out per minute. Cardiorespiratory System • The CR system consists of the heart, blood vessels, and the respiratory system. • The CR system picks up and transports oxygen, nutrients, and other substances to the organs and tissues that need them. • The CR system then picks up waste products and carries them to where they are expelled. • Cardio means “heart” • Respiratory means “lungs” Cardiorespiratory System Cardiorespiratory System • Blood vessels – Arteries = vessels that carry blood away from the heart – Veins = vessels that carry blood to the heart – Capillaries = very small blood vessels that distribute blood to all parts of the body Respiratory System • Alveoli = tiny air sacs in the lungs through whose walls gases such as oxygen and carbon dioxide diffuse in and out of the blood • Lungs expand and contract about 12–20 times a minute at rest Respiratory System • This system supplies oxygen to the body, carries carbon dioxide away • Pressure changes brought about by the contraction and relaxation of the diaphragm and rib muscle allow air to be drawn from the atmosphere into throat and eventually flow from the bronchi to air sacs called alveoli • Gas exchange occurs at the alveoli and allows oxygen to return to the heart and systemic system while removing carbon dioxide. • The ability to pick up and deliver oxygen is critical for the functioning of the body The Heart • The heart is divided into two halves by a wall (septum) and each half is divided into an upper chamber (atrium) and a lower chamber (ventricle). • The heart is a double pump. The right heart (pulmonary: lungs) has the task of transporting deoxygenated blood to the lungs where it can exchange carbon dioxide for a fresh supply of oxygen. • From the lungs, the oxygen-rich blood enters the left side (systemic: body) so that it can be sent out to the rest of the tissues in the body. • The tissues extract their oxygen and give up waste products (carbon dioxide), to the blood. The blood returns to the right side of the heart where the cycle begins again. Blood Flow Pattern Capillaries (Exchange) ↑ Alveoli ↑ LUNGS HEART Left Atrium ↓ Mitral Valve ↓ Left Ventricle Pulmonary Artery ↑ Pulmonary Valve ↑ Right Ventricle Aortic Valve ↓ Aorta HEART Right Atrium Superior Venae Cavae ↑ Veins ↑ Venules Arteries of each organ ↓ Arterioles of each organ ↓ Capillaries of each organ (Exchange) Circulation in the Heart Cardiorespiratory System At Rest and With Exercise Heart Rate Rest Exercise 50-90 bpm Up to 170-210 bpm Respirations Rest Exercise 12-20 breathes per minute 40-60 breathes per minute Blood Pressure Rest Exercise (Systole=Contraction Diastole=Relaxation) 110/70 175/65 Cardiac Output (SV x HR) Rest 5 quarts/min. Exercise 20 or more quarts/min. ENERGY PRODUCTION • • • Energy is required to fuel vital body functions and represents the capacity to perform physical work. Metabolism is “The sum of all the chemical processes necessary to maintain the body.” The rate at which your body uses energy (metabolic rate) depends on your level of activity. More Active → More Energy • Energy from food – Broken down into glucose – Stored as glycogen • ATP (adenosine triphosphate): The energy “currency” of cells ~ The body converts chemical energy from carbohydrates, fats, protein into substances that cells can use as fuel (ATP). ATP is the primary energy source for biological work. These fuels can be used immediately or stored. ATP must be restored at the same rate it is being used. There are 3 major energy systems the body uses to produce ATP ~ ~ ~ ~ ENERGY SYSTEMS Body’s Energy Systems IMMEDIATE (Anaerobic) NONOXIDATIVE (Anaerobic) OXIDATIVE (Aerobic) Energy Systems Duration of activity for which system dominates Immediate Non-oxidative Oxidative 0-10 seconds 10 seconds-2 minutes > 2 minutes High Low to moderately high Intensity of activity for which system predominates High Rate of ATP Production Immediate, very rapid Rapid Slower, but prolonged Fuel ATP, CP Muscle stores of glycogen and glucose Body stores of glycogen, glucose, fat, and protein Oxygen used? No No Yes Sample activities Weight lifting, picking up a bag of 400 meter run, groceries, jumping running up a flight of up stairs 1500 meter run, 30 minute walk, long, slow jog Energy System Facts • Lactic Acid is produced in the non-oxidative system which interferes with muscle contraction. Thus fatigue sets in. • Activities performed at less than 50% of one’s oxygen capacity → primarily use fat! • Activities sustained above 80% of one’s capacity → carbohydrates. • Fat is not utilized as a fuel source during high-intensity anaerobic activity because the lactic acid blocks epinephrine, a fatmobilizing hormone, which makes fat available from it storage units. Energy System Facts • Anaerobic activity are fueled entirely by carbohydrate metabolism which is a limited source of ATP. • For exercise to be aerobic, the intensity is such that the oxygen needs can be adequately met by the body during the activity – a “steady state” between supply and demand. • Oxidative ATP production occurs in the mitochondria. The mitochondria can use either glucose or fats to produce ATP, based upon intensity. Effects of Regular Cardio-Respiratory Endurance Exercise Immediate effects • • • • • • • • • • Increased level of neurotransmitters and certain hormones, especially epinephrine which stimulates a rise in all body functions Constant or slightly increased blood flow to the brain. Increased heart rate and stroke volume (amount of blood pumped per beat). Increased pulmonary ventilation (amount of air breathed into the body per minute). More air is taken into the lungs with each breath and breathing rate increases. Reduced blood flow to the stomach, intestines, liver, and kidneys, resulting in less activity in the digestive tract and less urine output. Increased systolic blood pressure; Increased blood flow and oxygen transport to working skeletal muscles and the heart; Increased oxygen consumption. As exercise intensity increases, blood levels of lactic acid increase. Increased energy (ATP) production. Increased blood flow to the skin and increased sweating to help maintain a safe body temperature. Long-term effects • Improved cognitive functioning and ability to manage stress; decreased depression, anxiety, and risk for stroke. • Increased heart size and resting stroke volume; lower resting heart rate. • Risk of heart disease and heart attack • significantly reduced. • Improved ability to extract oxygen from air during exercise. • Reduced risk of colds and upper respiratory tract infections • Increased sweat rate and earlier onset of sweating, helping to cool the body. • Increased blood volume and capillary density; • Higher levels of high-density lipoproteins (HDL) and lower levels of triglycerides; lower resting blood pressure and reduced platelet stickiness (a factor in coronary artery disease). • Reduced risk of colon cancer and certain other forms of cancer. • Increased number and size of mitochondria in muscle cells; • increased amount of stored glycogen; increased myoglobin content; • improved ability to use lactic acid and fats as fuel. • All of these changes allow for greater energy production and power output. • Insulin sensitivity remains constant or improves, helping to prevent Type 2 diabetes. • Fat-free mass may also increase somewhat. • Increased density and breaking strength of bones, ligaments, and tendons; reduced risk for osteoporosis. • Decreased body fat. The Effects of Exercise Immediate Effects: *Increase in HR, since higher demand for oxygen. *Increase in BP, as a result of ↑ blood flow. *Increase in supply, delivery, and use of oxygen by muscle. *Increase in body temperature. *Increase in certain hormones, especially epinephrine which stimulates a rise in all body functions. *Increase in metabolism. The Effects of Exercise Long-term (Training) Effects *Heart function and the ability to carry oxygen to the body is improved with endurance exercise. *Capacity of cells to take up and use oxygen improves. *Increased size of the heart: the walls become thicker and stronger, allowing for greater efficiency. *Increased blood volume, (the amount of plasma) therefore, more blood is pushed into circulation with each contraction. *Increased stroke volume – the amount of blood pumped with each contraction. *Improved cardiac output (SV x HR): the amount of blood pumped per minute. *Decreased resting pulse rate: as stroke volume increases, the body’s need for blood will be met with less beats per minute. *Decreased exercise pulse rate, heart operates more efficiently, with longer periods of rest. *Faster resting pulse rate recovery after exercise. *Reduced resting BP with endurance training. *Increased blood flow to the skin and sweating to release heat. *Decrease in the amount of body fat. *Increased size of muscle fibers. *Increased muscle strength and endurance. *Improved respiratory responses – depth of each breath increases, muscles that support breathing improve, better efficiency of system. *Reduced stress. Metabolic Responses • Improves Maximal Oxygen Consumption (VO2 Max )- This is determined by the body’s ability to uptake, distribute, and utilize oxygen. • There is a limit to the body’s ability to transport and use oxygen and is determined partly on genetics and partly on fitness status. The is the best overall assessment of the cardiorespiratory system. • The more fit you are, the more oxygen the blood carries, the higher the rate the oxygen is distributed to the tissues and the higher the levels of oxygen extracted from the blood at the capillary level. • The improvement in VO2 Max is caused by physiological adaptations: – Increased size and number of mitochondria (powerhouse of cell) where oxygen is utilized to produce ATP. – Enzymes needed by mitochondria to produce ATP ↑, thus more energy. – Increase in cardiac output, thus more oxygen available and extracted to use. Cardiorespiratory Endurance • PURPOSE of a CRE Program is to develop the body’s ability to deliver oxygen to the working muscles and tissues. • The quantity and quality of activity will differ based on the goals of health-related benefits or fitness-related benefits. HEALTH-RELATED BENEFITS – Include a reduced risk of certain diseases through moderate activity, but can occur without any significant change in an individual’s functional capacity or physical fitness. FITNESS-RELATED BENEFITS-require a higher level of activity. These benefits are related more to performance levels in sport and higher levels of lifestyle activities. When fitness-related benefits are achieved, health-related benefits also occur. Benefits of a CRE Program • Reduced risk of chronic disease. – Cardiovascular disease – CRE training has positive effects on serum lipids such as cholesterol and triglycerides. High levels of cholesterol can lead to a heart attack and stroke because they contribute to formation of fatty deposits in the arteries. – Cancer – CA is the second leading cause of death in U.S. Studies have shown a decreased risk of colon cancer, breast and reproductive system cancers. – Diabetes – Regular exercise helps prevent the development of Type II diabetes. Obesity is a key risk factor for diabetes and exercise helps keep body fat at healthy levels. Exercise burns excess sugar and makes cells more sensitive to insulin. – Osteoporosis – Exercise helps to prevent loss of bone density and poor bone strength. Benefits of CRE Program • Better Control of Body Fat -Body chemistry is influenced by endurance exercise and results in a better regulated energy balance. -Exercise burns calories directly and continues to do so by raising resting metabolic rate for several hours following exercise. -Increased proportion of lean body mass. • Improved Immune Function -Exercise can be either positive or negative on the immune system. It depends on the amount of exercise. Moderate exercise enhances immune function, while overtraining depresses the immune system. -Diet, stress management and sleep will also play a role in immune function. Evaluating CRE • There are simple tests to measure or estimate the VO2 max or your level of cardio-respiratory fitness. • In lab, a 1.5 mile run or a 1 mile walk will be administered. • Other tests include a 3 minute step test or a bicycle test or treadmill tests. Setting Goals *You can use your CRE assessment results to set a specific VO2 goal and improve your fitness category. *The amount of improvement depends on age, health status, and initial fitness level. *Another type of goal can be a time or distance goals. *Achieve the Surgeon General’s goal of 30 minutes/day, expending at least 150 calories. FITT PRINCIPLES • FREQUENCY – Recommended 3-5 days/week for normal, healthy individuals. Highly fit individuals may do daily activity. Training less than 3 days/week will not improve fitness. • INTENSITY – This is the most important component in achieving training effects. Intensity is inversely related to duration. Follow a plan of Progressive Overload, in which the amount of exercise is progressively increased, as the body adapts to the demands of exercise placed upon it by improving its functioning. -To determine intensity follow one of these methods: A. Percentage of Max Heart Rate B. Percentage of Heart Rate Reserve C. Rate of Perceived Exertion (RPE) Monitoring Your Heart Rate • Carotid artery in the neck • Radial artery in the wrist • Count beats for 10 seconds and multiply the result by 6 to get rate in beats per minute Heart Rate Maximum Heart Rate: 220 – age = _________bpm 55% intensity = MHR x .55 = ___________bpm 90% intensity = MHR x .90 = ___________bpm Target heart rate range = _______bpm to ________bpm 220 – 20 = 200 bpm 200 x .55 = 110 bpm 200 x .90 = 180 bpm Target heart rate range = 110-180 bpm Heart Rate Reserve Step 1: Maximum Heart Rate: (Male ) 220 – age = _________bpm (Female) 226 – age = _________bpm Step 2: Find HR Reserve: MHR – Resting HR = HRR Step 3: Find % of HR reserve (50% - 85%) HRR x .50 = _______bpm (low end) HRR x .85 = _______bpm (high end) Step 4: Find target HR range Target HR range = % of HRR + resting HR Ratings of Perceived Exertion (RPE) • Ratings of perceived exertion (RPE) • When you are training in your target heart rate zone, you should rate intensity as somewhat hard to hard. It is usually quite accurate. • Talk test FITT Principles ~ Time (Duration)– The length of time depends upon the intensity. Lower Intensity → More time (45-60 Min.) Higher Intensity → Less time (20 min.) ACSM recommends 20 – 60 minutes of continuous aerobic activity. If intermittent activity is incorporated, a minimum of three 10-minute bouts should be accumulated over the day. Longer duration, low-to-moderate intensity activities usually result in more gradual gains in max oxygen consumption. ~ Type – Cardio-respiratory endurance exercises include activities that involve the rhythmic use of large muscle groups for an extended period of time. Examples: Jogging, walking, cycling, kickboxing, swimming, skiing PROGRESSION • Rate of Progression depends on age, health status, initial level of fitness, goals and motivation! It is specific to the individual. • Your fitness improves when you overload your body • Initial stage (3–6 weeks): 3–4 days per week, low end of target heart rate zone, 20–30 minutes • Improvement stage (4–6 months): 3–5 days per week, middle to upper end of target heart rate zone, 25–40 minutes Maintaining Cardiorespiratory Fitness Maintenance Stage Improvements to fitness are not indefinite There comes a time when your fitness levels will reach a limit By the 4th – 6th month, you may reach an acceptable level of fitness and wish to maintain this by continuing every 3rd day Reaching this level requires setting new goals or adjustments to maintain motivation Cross-training can help boost enjoyment and prevent injuries Components of a Cardiorespiratory Exercise Session • WARM-UP – It is important to prepare the body for activity. It is important to increase muscle temperature before more intense work. • AEROBIC CONDITIONING – This phase should follow all the FITT principles. It is important to sustain the exercising HR for 20-60 minutes at the appropriate exercising intensity. • COOL-DOWN – This is important to gradually return the body to a normal resting rate. Plan a cool down for about 10-15 minutes. This is a great time to perform flexibility work. PREVENTING EXERCISE INJURIES • Whenever you participate in physical activity, there is a chance for injury. • A fitness assessment is crucial prior to exercise. • HOT WEATHER AND HEAT STRESS – Dehydration – “Thirst is not an accurate means for measuring or determining dehydration.” You have already started the dehydration process when you sense thirst. Hydrate early. Drink before, during, and after a workout! – Heat Injuries • Heat Cramps – The least serious of the heat-related injuries. Associated with activities that involve prolonged, profuse sweating. Usually caused by muscle fatigue, especially with children. Need to stretch, replace fluids, rest. • Heat Exhaustion – Involves rapid, weak pulse, low bp, dizziness, profuse sweating, muscular weakness, some cases disorientation. Replace fluids, rest. • Heat Stroke – CALL 911 – Dangerously elevated body temperature, failure of brain’s temperature regulatory system, life threatening, hot dry skin, cessation of sweating, sudden collapse with confusion or loss of consciousness, erratic behavior. Victim needs to be cooled as soon as possible! COLD WEATHER • Hypothermia – Core body temperature drops, sleepiness, low metabolic rate. A body temperature of 95 degrees or less signals the onset of hypothermia. Dampness, wind and fatigue can also cause hypothermia. Signs include change in mental status, cold abdomen, shivering, loss of coordination, difficulty speaking. Dress properly, cover head and hands, layer clothing. • Frostbite – Freezing of body tissues. Usually occurs in exposed body parts – earlobes, fingers, toes. Can cause permanent damage. • Take into account wind chill when exercising outdoors! Wind Chill Source: National Weather Service TREATMENT OF INJURIES USING RICE • Cryotherapy, or externally applying ice, is one of the best and immediate treatments for activity related injuries. Ice constricts the blood vessels to help with swelling. • R – REST the injured site. • I – ICE the injury regularly for 36-72 hours after an injury or until all the swelling is gone. Apply the ice for 15-20 minutes, then remove for at least 30 minutes. • C – COMPRESSION – Wrap the site in an effort to reduce swelling and fluid collection. An elastic bandage works well. • E – ELEVATION -Elevate the injured limb to reduce swelling and pain. Ideally raise the injured area above the heart, placing the injured area on pillows. Heat is appropriate for most injuries after 72 hours or after all the swelling is gone. OTHER CONCERNS • Do not attempt to self-diagnose or train through pain. Pain is an indicator that something is wrong and activity should be stopped until the source of pain is identified and your physician gives permission to begin again. • Wear Proper Shoes – Consult with an experienced athletic shoe salesman for proper shoes. • Environmental Conditions – Take into consideration temperature, air pollution, wind-chill, altitude and humidity when exercising outdoors. Dress appropriately for the conditions. • Illness – Use common sense when ill. If you have a cold (above the neck) and no fever, a light workout may be appropriate. If a fever is present, extreme fatigue, muscle aches, flu-like symptoms, avoid exercise until well. • Night Exercise – Be responsible and visible. Wear white clothing, reflective gear. Use a flashlight. Stay in a safe, well-lit area. Don’t go alone! Carry ID. Face oncoming traffic when possible. Let someone know your route and expected time back. TIP FOR THE DAY • Without a strong heart, nothing else matters. Perform weekly aerobic exercise to condition the body!