Cardiorespiratory Endurance 6 Cardiorespiratory Endurance

Cardiorespiratory Endurance Ability of lungs, heart, and blood vessels to deliver enough oxygen to cells to meet demands of prolonged physical activity The most important part of health-related physical fitness Lack of physical activity leads to hypokinetic diseases such as hypertension, heart disease, chronic low back pain, and obesity Aerobic exercise is especially important in preventing cardiovascular disease

Basic Cardiorespiratory Physiology CR endurance measures how pulmonary, cardiovascular, and muscular systems work together during aerobic activities Oxygen taken up by alveoli in the lungs and transported in blood hemoglobin, and then through the circulatory system Oxygen converts food into ATP through aerobic metabolism Oxygen uptake, or VO2 – indicates more efficient CR system

Key Terms Alveoli Hemoglobin Air sacs in the lungs where oxygen is taken up and carbon dioxide (produced by the body) is released from the blood Hemoglobin Iron-containing compound, found in red blood cells, that transports oxygen

Key Terms Adenosine triphosphate (ATP) Oxygen uptake (VO2) A high-energy chemical compound that the body uses for immediate energy Oxygen uptake (VO2) The amount of oxygen the human body uses

Aerobic and Anaerobic Exercise Cardiorespiratory endurance activities are called aerobic exercises Requires oxygen to produce energy (ATP) to carry out the activity Examples: walking, jogging, swimming Anaerobic exercise is so intense that oxygen can’t be delivered and used to produce energy Does not require oxygen to produce the necessary energy (ATP) to carry out the activity.

Benefits of Aerobic Training Higher maximal oxygen uptake (VO2max) Increase in oxygen-carrying capacity of blood Decrease in resting heart rate (RHR) Increase in cardiac output and stroke volume Cardiac output: amount of blood pumped by the heart in one minute Stroke volume: amount of blood pumped by the heart in one beat

Benefits of Aerobic Training (cont’d.) Beneficial physiological adaptations (cont’d.) Lower heart rate at given workloads Load placed on body during physical activity Increase in number, size, and capacity of mitochondria Structures within cells where energy transformations take place Increase in number of functional capillaries Smallest blood vessels carrying oxygenated blood to the body

Benefits of Aerobic Training (cont’d.) Beneficial physiological adaptations (cont’d.) Faster recovery time after exercising Time the body takes to return to resting levels after exercise Lower blood pressure and blood lipids Increase in fat-burning enzymes

Critical Thinking

Physical Fitness Assessment Assessment serves several purposes: Educate participants about current fitness levels Motivate individuals Provide starting point Evaluate improvements in fitness Monitor changes throughout the years

Responders versus Nonresponders Principle of individuality: genetics play a role in response to exercise Responders readily show improvements Nonresponders exhibit small or no improvements at all A lower-body strength-training program has been shown to help nonresponders improve VO2max through aerobic exercise

Assessment of Cardiorespiratory Endurance Aerobic capacity determined by oxygen uptake per minute of physical activity (VO2max) Higher levels = greater efficiency Relative value in mL/kg/min is used most often

Assessment of Cardiorespiratory Endurance (cont’d.) Components of VO2max Heart rate (beats per minute) and maximal heart rate (MHR) Stroke volume (mL per beat) Amount of oxygen removed from blood (mL of O2 per 100 cc of blood) Arterial-venous oxygen difference (a-vO2diff)

Key Terms Maximal heart rate (MHR) Arterial-venous oxygen difference Highest heart rate for a person, related primarily to age Arterial-venous oxygen difference Amount of oxygen removed from the blood as determined by the difference in oxygen content between arterial and venous blood

Assessment of Cardiorespiratory Endurance (cont’d.) VO2 is computed using the following equation: VO2 in L/min = (HR x SV x a-vO2diff) ÷ 100,000 HR = heart rate SV = stroke volume VO2max is affected by genetics, training, gender, age, and body composition VO2max decreases 1% per year starting at age 25 0.5% per year in physically active individuals

Tests to Estimate VO2max Five tests used to assess CR fitness: 1.5-Mile Run Test 1.0-Mile Walk Test For those unable to run; heart rate of at least 120 bpm Step Test Astrand-Rhyming Test 12-Minute Swim Test

1.5-Mile Run Test Figure 6.2. Procedure for the 1.5-mile run test.

1.0-Mile Walk Test Figure 6.3. Procedure for the 1.0-mile walk test.

Step Test Figure 6.4. Procedure for the Step Test.

Astrand–Rhyming Test Figure 6.5. Procedure for the Astrand-Rhyming Test.

12-Minute Swim Test Figure 6.6. Procedure for the 12-minute swim test.

Critical Thinking

Interpreting the Results After obtaining VO2max, you can determine your current level of CR fitness Locate the VO2max in your age category, and find your present level of CR fitness on the top row

Cardiorespiratory Fitness Classification Table 6.8. Cardiorespiratory Fitness Classification According to Maximal Oxygen Uptake (VO2max)

Principles of CR Exercise Prescription Adherence to exercise is enhanced if you are able to make it through 4 to 6 weeks of training The first step is to ask yourself: Am I ready to start an exercise program?

Guidelines for CR Exercise Prescription To develop the CR system, the heart muscle has to be overloaded FITT-VP Frequency Intensity Time (duration) Type (mode) Volume Progression

Intensity of Exercise Cardiorespiratory stimulation: make heart pump faster for a specified time period Health and fitness benefits 30 to 85% of heart rate reserve (HRR) Appropriate duration and frequency

Intensity of Exercise (cont’d.) Determine the intensity of exercise or cardiorespiratory training zone: MHR = 207 – (.7 x age) HRR = MHR – RHR Calculate TIs at 30, 40, 50, 60, 70, 85% % TI = [HRR x (%)] + RHR

Key Terms FITT-VP Vigorous exercise Moderate exercise Frequency, intensity, type, time, volume, progression Vigorous exercise High intensity level (>70% max) Moderate exercise Noticeably increases heart rate and breathing

Key Terms Heart rate reserve (HRR) Cardiorespiratory training zone Maximal minus resting heart rate Cardiorespiratory training zone Recommended training intensity range to obtain adequate cardiorespiratory endurance development

Moderate- vs. Vigorous-Intensity Exercise As intensity increases, adherence decreases, and injuries increase Moderate-intensity physical activity (about 50 percent TI) provides many health benefits, including decreased risk for cardiovascular mortality Vigorous-intensity programs yield higher improvements in VO2max

Recommended Cardiorespiratory or Aerobic Training Pattern Figure 6.7. Recommended cardiorespiratory or aerobic training pattern.

Monitoring Exercise Heart Rate Count your pulse for 10 seconds, then multiply by six to get the per minute pulse rate Monitor regularly in beginning of program Make sure you are in the proper zone Assess activity level based on pulse rate Consider personal fitness goals

Rate of Perceived Exertion (RPE) A perception scale to monitor or interpret the intensity of aerobic exercise Alternative to checking pulse Rate of exercise difficulty Cross-check with target zone Reexamine periodically

Perceived Exertion Scale Figure 6.9. Physical activity perceived exertion scale

Mode of Exercise The mode, or type, of exercise that develops the CR system has to be aerobic in nature Involves major muscle groups Choose activities based on personal preferences

Mode of Exercise (cont’d.) Optimal health benefits Lower end of cardiorespiratory zone Greater improvements Higher end of cardiorespiratory zone Specificity of training Use same mode for exercise as testing

Duration of Exercise Exercise between 20 to 60 minutes per session Up to 90 minutes daily may be required to prevent weight gain Even accumulation of 30 min moderate activity, conducted for at least 10 minutes three times per day, benefits the CR system 5 hours of moderate activity, or 2.5 hours of vigorous activity per week provide additional benefits

Duration of Exercise (cont’d.) Novice and overweight exercisers need proper conditioning prior to vigorous exercise to avoid injuries or cardiovascular-related problems Exercise sessions always should be preceded by a 5- to 10-minute warm-up and be followed by a 10-minute cool-down period A warm-up consists of general exercises at a lower intensity than the actual target zone

Frequency of Exercise Recommended exercise frequency for aerobic exercise is 3 to 5 days per week Three 20- to 30-minute exercise sessions per week, on nonconsecutive days, are sufficient to improve (in the early stages) Endurance athletes may train at or above the anaerobic threshold

Key Terms Anaerobic threshold Volume of exercise The highest percentage of the VO2max at which an individual can exercise (maximal steady state) for an extended time without accumulating significant amounts of lactic acid Volume of exercise The product of frequency, intensity, and duration Minimum volume of 1000 calories per week recommended

Excessive Sitting: A Deadly Proposition People who sit most of the day have up to a 50% greater risk of dying prematurely and an 80% greater risk of cardiovascular disease Ways to enhance daily nonexercise activity thermogenesis (NEAT) Stand as much as possible; use a standing or a treadmill desk; use a stability ball for a chair; hold “walking” meetings; walk to co-workers’ offices instead of phoning; take intermittent breaks; park farther away; take the stairs

Rate of Progression Rate of progression depends on health status, exercise tolerance, and program goals Initially, only three weekly training sessions of 15 to 20 minutes are recommended to avoid musculoskeletal injuries Increase duration by 5-10 minutes per week and frequency up to 5 times per week by the fourth or fifth week Progressively increase frequency, duration, and intensity of exercise until you reach your fitness maintenance goal

Physical Activity Pyramid Figure 6.10. The physical activity pyramid.

Fitness Benefits of Aerobic Activities Effort determines benefits and physiological development Beginners should start with light-intensity activities that carry a minimum risk for injuries METs (metabolic equivalents) measure intensity of exercise in multiples of resting metabolic rate 1 MET is the equivalent of a VO2 of 3.5 mL/kg/min MET levels for a given activity vary according to the effort expended

Getting Started The first few weeks are the most difficult Reduce muscle soreness, stiffness, and risk for injuries by gradually increasing exercise intensity, duration, and frequency Once you begin to see positive changes, it won’t be as hard

A Lifetime Commitment to Fitness Benefits are maintained through a regular lifetime program Four weeks of aerobic training are completely reversed in two weeks of physical inactivity Staying with a physical fitness program long enough brings about positive physiological and psychological changes

Assess Yourself Do you consciously attempt to incorporate as much physical activity as possible in your daily living? Do you understand the following concepts? Cardiorespiratory endurance training Aerobic and anaerobic exercise Assessing cardiorespiratory fitness 1.5-mile run test, 1.0-mile walk test, step test, Astrand-Rhyming test, 12-minute swim test