Chapter 4 cardiorespiratory fitness

COMING UP IN THIS CHAPTER Learn how your cardiorespiratory system works and what affects its functioning Discover the benefits of cardiorespiratory fitness Assess your level of cardiorespiratory fitness Develop a personalized cardiorespiratory fitness program

Factors Affecting Cardiorespiratory Fitness Cardiorespiratory fitness (CRF) The ability of the circulatory and respiratory systems to sustain physical activity Also known as cardiorespiratory endurance, aerobic fitness, or aerobic endurance

Factors Affecting Cardiorespiratory Fitness I have a friend on the track team. I tried running with her once and it was so hard. Why is it so easy for her? Things to consider: Genes Health Cardiorespiratory (CR) conditioning Nutrition Training

The Condition of the Cardiorespiratory System What are the parts of the system that make my muscles go? Major components of the cardiorespiratory (CR) system: Heart Lungs Network of blood vessels (vascular system)

The Condition of the Cardiorespiratory System Heart Acts as muscle pump to circulate blood Lungs Take in oxygen and expel carbon dioxide; exchange takes place in the alveoli Respiratory system: air passages, lungs, breathing muscles

The Condition of the Cardiorespiratory System Vascular system Circulates blood to lungs and around body Arteries: carry blood away from heart Veins: carry blood toward the heart Capillaries: tiny blood vessels with thin walls; substances can pass between the blood they carry and the surrounding cells and tissues

Figure 4-1 The cardiorespiratory system

Figure 4-2 Circulation of oxygen and carbon dioxide

The Condition of the Cardiorespiratory System When I try to run fast, why does it feel like I can’t breathe? As exercise intensifies, CO2 and lactate (lactic acid) accumulate Increased ventilation lowers both In fit individuals, this effect is lessened Increased CR system efficiency is directly related to increased training

Figure 4-3 Increase in breathing rate during exercise

The Condition of the Cardiorespiratory System Can I eat before I exercise? It depends on the type of exercise Exercise redirects blood to active muscles Less blood to the gut to help digest Can result in “side stitch”

Energy Production I feel tired all the time. What can I do to get more energy? Energy level versus energy production: Adenosine triphosphate (ATP) is fuel for muscles Catabolism ATP is produced from carbohydrate, fat, or protein Carbohydrates are the main source Converted to ATP from blood glucose or from carbohydrates stored in the liver and skeletal muscle (glycogen)

Energy Production Carbohydrates (glucose or glycogen) are stored in limited amounts, but are the most readily converted Preferred energy source for ATP Fats have unlimited storage but do not convert readily to ATP Beta-oxidation Protein has limited storage; it is inefficient for energy conversion Distant third choice for energy

Energy Production The three energy systems that can produce ATP and generate energy: ATP/CP energy system Short duration, less than 10 seconds Glycolytic energy system Activities that last longer than 10 seconds Aerobic energy system Occurring in the presence of oxygen

Energy Production ATP/CP energy system When the body needs energy fast Anaerobic Ideally suited for extremely short bouts of activity Jumping, throwing, lifting, sprinting Can replenish itself rapidly Fueled by stored ATP and creatine phosphate (CP) Stored creatine is critical Red meat is the best source of this compound

Energy Production Glycolytic energy system This system will take over when activities last more than 10 seconds Anaerobic Glycolysis Pyruvate (pyruvic acid) Can be converted to lactate under certain conditions Relatively inefficient at generating ATP Best suited for activities that last up to 90 seconds

Energy Production How is aerobic exercise different, and why is it so important? To build cardiorespiratory fitness (CRF), you’ll need to perform activities that primarily use the oxygen-dependent aerobic energy system It does not produce ATP fast enough for a brief, all-out intense effort When oxygen is present, the potential for ATP production increases dramatically when compared to the other systems Mitochondria

Figure 4-4 Time span of action of the three energy systems

Diseases Affecting the Cardiorespiratory System Can you still achieve cardio fitness if you have something like asthma? Is cardio exercise safe after a heart attack? Asthma and COPD (chronic bronchitis and emphysema) Can exercise; but frequency, intensity, duration, and type of exercise may be restricted Cardiovascular disease Exercise is critical in both primary and secondary prevention

Genetics I don’t like to exercise, and neither do my parents. Is my problem genetic? How much you like exercise not affected by genes, but genetics may play role in your ability to get fit No more than 50% of your ability to improve your cardio respiratory fitness is inherited The other half is based on how active we are and what activities we engage in

Biological Sex How do men and women differ in getting fit? Men and women have the same ability to increase their levels of cardiorespiratory fitness Men can typically achieve a higher absolute level of cardiorespiratory function Difference is in size between the sexes

Use and Age My dad is 58 and wants to start exercising. Is he too old? It is never too late to start a fitness program A natural result of aging is a steady decline in the functioning of the cardiorespiratory system The rate of decline is lower in those who exercise on a regular basis “Use it or lose it”

Improved Performance My boyfriend made me do an online fitness survey and it said my VO2 was 41. What does that mean? VO2: volume of oxygen consumed over time Largely determined by the amount of oxygen you bring into your lungs, which is affected by size VO2max: maximum amount of oxygen you can consume during peak exercise

Improved Performance Every time I start an exercise program I feel worse! Does it ever get better? Start gradually Over time: Your heart muscle will grow stronger Your lungs will become more efficient Your blood vessels will become more elastic Your cells will develop more mitochondria

Improved Performance If your heart is a muscle, can you bulk it up? The heart can grow in size (hypertrophy) Regular exercise allows the heart muscle to stay flexible Greater stroke volume Higher cardiac output

Reduced Risk of Disease My mom’s doctor told her to walk every day to help lower her blood pressure. Does just walking really work? Positive effects of physical exercise: Improved blood pressure Improved cholesterol levels Reduced risk of type 2 diabetes Reduced risk of certain cancers Reduced risk of osteoporosis Reduced risk of cardiovascular disease (CVD)

Figure 4-5 Summary of the effects of cardiorespiratory exercise

Reduced Risk of Disease Will exercise make me live longer? Regular cardiorespiratory exercise may increase longevity and quality of life

Healthier Body Composition How much exercise do I need if I want to lose some serious weight before spring break? And what is the best weight-loss exercise? Healthy weight loss is 1–2 pounds per week A one-pound change in body weight represents a change of 3,500 calories through diet, exercise, or both The best choice of exercise is one that you will do regularly

Stress Management and Improved Emotional Wellness I feel better after exercising. Why is that? Almost any type of physical activity, moderate in duration and intensity, can cause feelings of elation Provides distraction Increases body temperature Changes brain chemistry

Types of Cardiorespiratory Fitness Tests How do my friend and I figure out who is more fit? Take the same type of CRF assessment Lab tests Field tests Resting heart rate assessment The usual point is for motivation

Types of Cardiorespiratory Fitness Tests Lab tests Measure VO2 accurately Metabolic cart Field tests Rockport walk test Walk a mile as quickly as possible 1.5-mile run/walk test 3 minute step test See Lab Activity 4-1

Types of Cardiorespiratory Fitness Tests Resting heart rate Measuring your true RHR doesn’t involve exercise at all Heart rate is counted for 1 full minute after waking

Evaluating Assessment Results and Setting Goals How much can I improve? How much do I really need to improve? Improvement varies Aerobic capacity can increase by 10–30% It is best to progress no more than 10% a week in frequency, intensity, or time (not all at once) Recall the principle of progressive overload

Evaluating Assessment Results and Setting Goals How often should I do an assessment to check for improvement in my cardio fitness? Can I judge my fitness without taking a test? Achieve goals, then set new ones Re-assess your fitness 4–6 weeks initially and then every 8–12 weeks Use your exercise performance as a guide Get baseline measurements

Getting Started How do I learn to like exercise? Right now, I just don’t. For a successful cardiorespiratory fitness program: Apply the FITT formula Include activities you enjoy and will stick with Finding exercise you like is most important

Applying the FITT Formula How do I know I’m doing the right things— not going too far, or too fast, or too slow? Use the FITT formula: Frequency Intensity Time Type

The FITT Formula: Frequency Is it safe to work out every day? Most guidelines encourage 1–2 days of rest to prevent injury and burnout Daily is fine if you vary routine, exercises, intensity Intensity and frequency need to be balanced ASCM: 3 days a week for vigorous intensity (for at least 20 minutes a day) and 5 days a week for moderate intensity Bouts of at least 10 minutes count toward the minimum- duration recommendation

The FITT Formula: Intensity How hard should I exercise? Exercise in your target intensity zone Balance with frequency and duration Intensity is tied to your personal goals Difference between moderate-intensity and vigorous-intensity: Two minutes of moderate activity confers the same benefit as one minute of vigorous activity

The FITT Formula: Intensity What’s considered moderate activity and vigorous activity? The talk test is a simple method for judging intensity Moderate-intensity exercise: you can talk but not sing Vigorous-intensity exercise: you can say only a few words before pausing to take a breath More…

The FITT Formula: Intensity Other methods for judging intensity: Heart-rate maximum method (HRmax) Exercising at certain percentage of maximum heart rate (MHR) Target heart rate = MHR × % Can also use age; subtracting age from 220 Target heart-rate range More…

The FITT Formula: Intensity Heart-rate reserve (HRR) method More complicated but more accurate Target heart rate = [(MHR – RHR) × %] + RHR RHR determined by counting pulse before you get out of bed Rating of perceived exertion (RPE) Subjective measure of exercise intensity Rate on scale of 6 to 20 Metabolic equivalents (METs) Estimates amount of oxygen body uses during physical activity

Table 4-1 Recommended Starting Intensity Of Exercise Based on Current Activity Level

Figure 4-7 Rating of perceived exertion (RPE) scale

Applying the FITT Formula What’s the best way to take my heart rate when I’m exercising? Heart-rate monitor Fingers on the inside of the wrist at the radial artery or on the neck by the carotid artery

Applying the FITT Formula Doesn’t lower-intensity exercise burn more fat? What matters is total calories used Lower intensity uses more fat; higher intensity uses more overall calories and total fat

Figure 4-8 Intensity Levels of different physical activities

Figure 4-9 Fat and carbohydrate used during exercise

The FITT Formula: Time How many hours of cardiovascular activity are necessary to be healthy? Balance time with intensity Individual workouts and weekly exercise plan: ACSM: moderate-intensity exercise at least 30 minutes/day, 5 or more days/week; or 20 minutes of vigorous exercise, 3 days a week HHS: 150 minutes of moderate-intensity or 75 minutes of vigorous intensity (doubling brings even greater health) Beware of time spent sitting

Figure 4-10 Relationship between exercise time and intensity

The FITT Formula: Type Cardiorespiratory fitness can improve through a variety of activities Those that are aerobic, rhythmic, and involve regularly performed work by large muscle groups Individual activities and team “pick-up” activities Outside or in the gym

Putting Together a Complete Workout Do I really need a warm-up just to go walking with my friends? No; because you will probably start off slower and increase speed as you go (you will in fact be warming up) A workout has three stages: Warm-up Conditioning Cool-down

Figure 4-11 Cardiorespiratory workout

Making FITT Work for You I don’t have much time to work out but I still want to get fit. What can I do? You need to consider your: Current level of fitness Schedule Activity options Preferences Goals

Table 4-2 Summary of Recommended Exercise Guidelines

Making Progress Toward Your Fitness Goals How long until I can run for 5 miles? Choose proper progression

Making Progress Toward Your Fitness Goals Do I need a special diet to increase cardio fitness? Diet can’t directly increase CRF, but it can go a long way in improving overall health Fitness gains come from training Diet impacts the quality of training

Making Exercise Safe I have a cold. Can I still work out? Yes, if you don’t have a fever and your symptoms are from the neck up Maybe at a slower pace or for a shorter duration If you have the flu, take time off and start back slowly

Personal Training Online, in Person, or Somewhere in Between? How do I know who is a good personal trainer? Look for certification and a relevant degree Ask for references Check the fees Read the fine print Discuss expectations

Fine-Tuning Your Program to Maintain Success and Enjoyment Is there anything in particular I should keep track of over time? Setting goals and tracking progress are good strategies for success You can track your miles, minutes, days per week, heart rate, RPE, etc. It helps in seeing your progress and in identifying problems

Fine-Tuning Your Program to Maintain Success and Enjoyment I get bored easily. Any suggestions? Investigate boredom-busting technology Add faster or higher intensity spurts (interval training) Cross-training Investigate skill-related sports

Sticking with Your Program—and Restarting It After a Lapse How am I supposed to stick with exercise over time? I’ve never had much luck. Maintaining an exercise program is the hard part Have a plan to prevent relapses 6–12 weeks before exercise becomes a routine

Sticking with Your Program—and Restarting It After a Lapse How do I find more time to exercise? Keep a time log to identify time to exercise Fit mini-exercises into the day

Sticking with Your Program—and Restarting It After a Lapse I used to exercise but haven’t for a while. What would you recommend for me since I’m just getting back into working out? Start back slowly Focus on progression without increasing too much or too fast