Cardiorespiratory Fitness chapter5 Cardiorespiratory Fitness

Anaerobic and Aerobic Exercise To perform work, the muscles do not use the energy released when food is broken down in the body. Instead, the body uses food to manufacture a substance called adenosine triphosphate (ATP), the primary energy molecule of the body. Only when energy is liberated from the breakdown of ATP can the cells so the body perform work. When ATP is generated by the process of using oxygen, metabolism is aerobic. When ATP is generated without the use of oxygen, metabolism is anaerobic.

Anaerobic Exercise With anaerobic exercise, ATP is needed quickly to perform an activity. Anaerobic activities do not depend on oxygen metabolism at all because the exercise intensity is high and the duration is less than 2 or 3 minutes. Two major anaerobic energy systems: Immediate energy system Lactic acid system

Immediate Energy System The intermediate energy system is used for high intensity activities that last less than 30 seconds: Running the 100-meter dash Lifting heavy weights Here, the muscles use ATP and creatine phosphate (CP) supplies that are already stored in the muscles.

Lactic Acid System The lactic acid system generates ATP for high-intensity activities lasting from 30 seconds to 3 minutes. In general, events or activities that require a combination of speed and power over a short time rely heavily on the lactic acid energy system: 400-meter run 800-meter run

Aerobic Exercise Exercises are referred to as aerobic when they depend on oxygen metabolism to generate ATP. Activities must last a minimum of 3 to 5 continuous minutes to generate most of the energy from aerobic energy systems.

Aerobic Fitness Aerobic fitness is often used interchangeably with several other terms. Aerobic power Cardiorespiratory fitness Cardiorespiratory endurance Maximal oxygen consumption It is the ability of the heart, blood vessels, and the lungs to deliver oxygen to the exercising muscles in amounts sufficient to meet the demands of the workload.

Maximal Oxygen Consumption (VO2max) . Maximal oxygen consumption is the optimal capacity of the heart to pump blood, of the lungs to fill with larger volumes of air, and of the muscle cells to use the oxygen and remove waste products produced during the process of aerobic metabolism. It is considered the single best indicator of cardiorespiratory fitness.

Benefits of Cardiorespiratory Fitness Enhanced ability to cope with stress Increased bone density and greater joint integrity Enhanced body composition Improved blood-lipid profile Faster recovery from an aerobic exercise session Improved submaximal exercise efficiency Increased maximal oxygen consumption (VO2max) .

Measuring Cardiorespiratory Fitness Factors such as age, gender, genetic background, and physical training influence VO2max. Men tend to have a higher level of aerobic power than women of similar ages do. After age 30, sedentary individuals experience a decrease in VO2max of about 1% per year. Typically, as you become older, your maximal level of aerobic power declines. . .

. VO2max . The VO2max, or aerobic power, of an individual is expressed in volume (in liters) per unit of time (in minutes). Scores ranging from 3 to 4 liters per minute are common for the average healthy individual who exercises three to four times per week. Highly trained endurance athletes may have a VO2max ranging from 5 to 6 liters per minute. People who engage in activities such as running, cross-country skiing, and cycling often have the highest measured VO2max. . .

Submaximal Tests . Direct measurement of the VO2max is not always practical. Instead, we recommend using submaximal tests, or field tests, to estimate or categorize aerobic fitness when testing large groups or older individuals who might be at risk. 1-mile walking test 1.5 mile-run test 12-minute run test 12-minute swimming test Åstrand-Rhyming cycle ergometer test

Myths and Facts Myth—Most Americans are getting enough aerobic exercise to reduce their risk of developing heart disease. Fact—More than 60% of adults do not achieve the recommended amount of regular physical activity, and 25% of adults are not active at all. Myth— Younger individuals have less need to stretch before exercising compared with older people. Fact— Whatever your age, being flexible helps you use your muscles more effectively and efficiently. Myth—You should exercise every day to increase your level of cardiorespiratory fitness. Fact—It is best to exercise on alternate days to allow adequate time for recovery.

Sample Jogging Program Frequency—The optimal frequency for jogging is every other day. Intensity—During the initial phase of your program, stay in the 60 to 75% THR zone. Time—In the initial phase of a jogging program, exercise for 15 to 30 minutes.

Sample Cycling Program Frequency—As with other forms of cardiorespiratory exercise, you should cycle 3 to 5 days per week. Intensity—Exercise at 60% of your THR zone. Begin a cycling exercise regimen by riding approximately 1 to 2 miles a session, increasing to 3 to 5 miles after several weeks. Time—Each cycling session should last approximately 30 to 45 minutes.

Factors to Consider When Selecting Activities 1. Impact (joint and body) 2. Intensity 3. Location 4. Weather 5. Social support 6. Regularity