Cardiovascular Fitness Notes

Chapter 7: Cardiovascular Fitness

Learning Objectives

Describe components of the cardiovascular system.
List health benefits of cardiovascular fitness.
Outline the FITT formula for cardiovascular fitness.
Identify methods for determining exercise intensity levels.
Describe guidelines for monitoring cardiovascular exercise (self-monitoring heart rate).
Indicate self-assessments for cardiovascular fitness.

Introduction

Cardiovascular fitness is crucial for overall physical fitness.
It reduces the risk of heart disease and premature death and enhances the quality of life.
Regular cardiovascular exercise extends health and wellness benefits beyond disease risk reduction.
Understanding the cardiovascular system is key to determining appropriate exercise intensity.

Elements of Cardiovascular Fitness

Cardiovascular fitness synonyms: cardiovascular endurance, cardiorespiratory fitness, and aerobic fitness.
Cardiovascular endurance: Ability to persist in physical activity for long periods without fatigue.
Cardiorespiratory fitness: Requires oxygen delivery and utilization through circulatory and respiratory systems.
Aerobic fitness: Aerobic capacity is the best indicator; aerobic activity is the preferred method.
Cardiovascular fitness is complex and requires fitness of several body systems.

The Heart Muscle

Good cardiovascular fitness requires a fit heart muscle.
The heart pumps blood throughout the body, approximately 40 million times a year.
The heart pumps over 4,000 gallons of blood daily.
A strong heart is crucial for an effective cardiovascular system.
Exercise strengthens the heart, increasing its size and pumping efficiency.
The heart pumps more blood per beat, reducing the number of beats needed.
Typical resting heart rate (RHR) is $70-80$ beats per minute, but highly trained athletes may have an RHR in the $40s$ or $50s$ .
A decrease in RHR with training indicates cardiovascular fitness improvements.

The Vascular System

Good cardiovascular fitness requires a fit vascular system.
The heart has four chambers pumping blood rhythmically for good circulation.
The left ventricle pumps oxygen-rich blood through the aorta to tissues.
Blood flows from arteries to capillaries to veins.
Veins carry oxygen-depleted blood back to the right side of the heart.
The right ventricle pumps blood to the lungs for oxygenation and $CO_2$ removal.
Oxygenated blood returns to the heart, entering the left atrium and then the left ventricle.
Arteries distribute oxygenated blood to tissues, muscles, and organs.
Healthy arteries are elastic and unobstructed, allowing for proper blood flow.
Muscle layers in arteries control arterial opening size via nerve impulses.
Unfit arteries may have reduced internal diameter (atherosclerosis) due to deposits or hardened walls (arteriosclerosis).
Blood in the heart's chambers doesn't directly nourish the heart; coronary circulation does.
Poor coronary circulation can cause a heart attack.
Deoxygenated blood returns through veins intertwined with skeletal muscles.
Muscle contraction squeezes veins, pushing blood back to the heart.
Valves in veins prevent backward blood flow; defects can lead to blood pooling.
Varicose veins: blood pooling in the legs.
Regular physical activity helps reduce blood pooling and keeps vein valves healthy.
Capillaries are transfer stations where oxygen and fuel are released, and waste products are removed.
Veins receive blood from capillaries for the return trip to the heart.

Blood and Respiratory System

Good cardiovascular fitness requires healthy blood and a fit respiratory system.
External respiration: Taking in oxygen and delivering it to the lungs, where it's picked up by the blood.
External respiration requires fit lungs and blood with adequate hemoglobin.
Hemoglobin carries oxygen through the bloodstream.
Lack of hemoglobin reduces oxygen-carrying capacity (anemia).
Internal respiration: Delivering oxygen to tissues from the blood.
Internal respiration requires adequate healthy capillaries, which also remove carbon dioxide.
Good cardiovascular fitness requires fitness of both external and internal respiratory systems.

Muscle Tissue

Cardiovascular fitness requires fit muscle tissue capable of using oxygen.
Muscle tissues use oxygen to sustain physical performance.
Physical activity promoting cardiovascular fitness changes muscle fibers to use oxygen more effectively.
Distance runners have well-conditioned muscle fibers for sustained running, activities elicit similar adaptations in specific muscles used.

Cardiovascular System During Exercise

During exercise, the cardiovascular system's performance is maximized.
Breathing rate and depth increase to take in more oxygen.
The heart beats faster and pumps more blood per beat (increased stroke volume).
Higher heart rate and larger stroke volume increase oxygen availability to muscles.

Terminology

Aerobic Capacity: A measure of aerobic or cardiovascular fitness.
Hemoglobin: The oxygen-carrying protein (molecule) of red blood cells.
Anemia: A condition in which hemoglobin and the blood's oxygen-carrying capacity are below normal.

Maximum Oxygen Uptake (VO2 max)

VO2 max is an indicator of cardiovascular fitness.
VO2 max (aerobic capacity) is measured in a laboratory by assessing oxygen use during maximal exercise.
The test is often performed on a treadmill with gas analyzers.
Treadmill speed and grade increase until oxygen use reaches its maximum.
The test indicates overall cardiovascular fitness dependent on the heart, blood vessels, blood, respiratory system, and muscles.

Cardiovascular Fitness and Health Benefits

Good cardiovascular fitness reduces the risk of heart disease, hypokinetic conditions, and early death.
Studies confirm that good cardiovascular fitness is associated with a reduced risk for heart disease.
A review of studies showed that low fitness correlated with a 70% higher death rate from all causes and a 56% higher death rate from heart diseases.
Benefits of cardiovascular fitness are independent of its effect on other risk factors.
Physical activity has beneficial effects on cholesterol, blood pressure, and body fat.
Cardiovascular fitness benefits are independent of these other effects.
Active/fit people have lower health risks even with cholesterol, blood pressure, and body fat levels identical to inactive/unfit people.
Physical inactivity is a major, independent risk factor for heart disease, equivalent to other established risks.
Good fitness reduces risks for normal weight, overweight, and obese people.
Physical activity builds cardiovascular fitness even in those with excess body fat.
A fit, overweight person has a lower risk of chronic disease than an unfit person with normal weight.
Low fitness is a greater risk than excess body fatness; the greatest risk is among people who are both unfit and overfat.
Good cardiovascular fitness enhances task performance, improves function, and is associated with wellbeing.
Moving out of the low fitness zone reduces disease risk.
Wellness benefits include the ability to enjoy leisure activities and meet emergency situations.
Cardiovascular fitness in the high-performance zone allows for high performance athletic events and jobs (e.g., firefighters).

The FIT Formula for Cardiovascular Fitness

The FIT formula varies for people of different activity levels.
Adaptations are based on the overload principle and the principle of progression.
An appropriate challenge should be provided to the cardiovascular system, increasing gradually as fitness improves.
Vigorous physical activity is generally needed to improve cardiovascular fitness; moderate activity improves fitness for those with low fitness.
The frequency of exercise is similar for different levels, but intensity and time spent vary.
The frequency (F) of physical activity to build cardiovascular fitness ranges from 3 to 5 or more days a week.
ACSM suggests at least 5 days a week of moderate physical activity for low-fit people.
Moderate activity can be safely performed daily and provides additional benefits.
Vigorous physical activity is recommended for more active people at least 3 days a week.
5 days a week is the maximal recommended dose for most people.
People who are fit, active, and without joint problems may train up to 6 days a week, but at least 1 day off is beneficial.
Fitness assessments should be completed to determine the appropriate exercise frequency.
Fit people need to exercise at a higher intensity to challenge the cardiovascular system.
Heart Rate (HR) indicates the challenge presented by exercise.
Intensity guidelines are based on percentages of heart rate reserve (HRR) or maximal heart rate (maxHR).
HRR range is 30 to 85 percent, and maxHR, 57 to 94 percent.
Lower intensities benefit low-fit people, while higher intensities are needed for more fit people.
The amount of time (T) for building cardiovascular fitness is based on minutes of activity per day.
Minimum recommendation: 150 minutes of moderate activity per week or 75 minutes of vigorous activity per week.
Extending exercise time has additional health and wellness benefits.
150 to 300 minutes of moderate activity per week aids in losing body fat and maintaining a healthy body weight.
Extending vigorous activity from 20 up to 90 minutes has health/wellness benefits and enhances cardiovascular fitness.

Maximal Heart Rate (maxHR)

An estimate of maximal Heart Rate (maxHR) is needed to determine appropriate target heart rate zones for aerobic exercise.
MaxHR is the highest heart rate attained during exercise.
MaxHR decreases with age, estimated by subtracting age from 220: $maxHR = 220 - age$

Guidelines for Heart Rate and Exercise Monitoring

Counting heart rate helps monitor physical activity intensity.
Each heartbeat pumps blood into arteries, causing a pulse.
Pulse can be felt by holding a finger against an artery.
Common arteries for pulse counts: radial (wrist) and carotid (neck).
Counting the pulse at the carotid is the most popular procedure.
Count pulse immediately after exercise; Locate the pulse first then stop and take a 15-second count. Multiply the number of pulses by 4 to convert heart rate to beats per minute or your 30-second pulse by two
Heart rate slows after exercise. The heart rate has already slowed considerably within one minute after activity ceases.
Locate the pulse quickly and count the rate for a short period to obtain accurate results