Unit 2

Aerobic Fitness

Objectives

• Gain knowledge in types of activity that are aerobic
• Understand how aerobic exercise reduces your risk of heart disease
• Learn how to begin and progress in an aerobic fitness plan

Focus Questions

1. What benefits could you personally experience if you started an aerobic fitness program?
2. If you currently engage in regular aerobic exercise, what benefits have you noted as a result of your endeavor?

Concepts

• Cardioprotective mechanisms
• Target heart rate
• Warm-up and Cool-down

Chapter 3

Wellness: Choices for Health & Fitness, Donatelle.

American Heart Association

Visit this web site to determine your activity level and follow the guide for increasing your physical activity. Link opens new browser window.

Study Guide

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Lecture Introduction

Aerobic Fitness is defined as the ability of the cardiovascular and muscular systems to provide energy to sustain large muscle group activity over an extended period of time. The aerobic fitness body systems include:

Pulmonary System: Lungs & Air Passageways

Oxygen is brought from the atmosphere into the lungs to be distributed to the body tissues. Tiny air sacs in the lungs are highly vascularized with capillaries. This is where the oxygen diffuses into the blood and waste gases are transferred from the blood to the air sacs, to be excreted out of the body through the mouth.

Cardiovascular System: Heart, Arteries, and Veins

The heart is the pump, the vessels that carry blood away from the heart are called arteries and the vessels that carry blood toward the heart are called veins.

Muscular System: Muscle fibers

The muscle fibers are highly vascularized with capillaries and this is where the exchange of gases, nutrients, and by-products occurs. Oxygen and nutrients are delivered to the muscle cells (fibers) or other cells of the body, whereas carbon dioxide, lactic acid, and other metabolic waste products are carried away from the cells.

Acute responses are the body’s responses to a single exercise bout. Ventilation increase as the body’s demand for oxygen goes up, you need to breathe harder or more frequently to get more air from which to extract the oxygen. Cardiac output or the total amount of blood delivered into the cardiovascular system per minute also increases. This is measured taking the heart rate and multiplying it by the stroke volume (stroke volume is the amount of blood pumped out of the heart with each contraction or beat of the heart) Systolic blood pressure, the pressure exerted on the walls of the arteries by blood as it flows through during heart contraction, increases as well.

Chronic Responses are the adaptations by the body to regular aerobic exercise. Resting heart rate decreases as your heart gets more efficient and stronger through regular aerobic exercise, it will pump more blood for each beat (increased stroke volume), thus it does not have to pump as many times at rest to provide the body with the same amount of blood and oxygen. VO2 max increases with aerobic exercise training. The body increases its capacity to efficiently utilize oxygen and thus VO2 max will increase. There is a genetic component to VO2 max limits; generally improvement levels at a 20% increase. VO2 max, is the maximal amount of oxygen the body uses to produce energy during exercise, which involves use of large muscle groups – this is the standard evaluation factor by which all tests of aerobic fitness are based.

General warm -up includes general movements to warm the body temperature and move joints through their range of motion, and specific targeted movements or stretches for muscle groups related to the activity. This prepares the cardiovascular system by increasing blood flow and elasticity of muscles. The specific warm-up is done through stretching the prime muscles movers specific to the activity. Cool-down is done after the workout and includes slower movements of the specific activity to decrease the heart rate and body temperature toward resting values. This is important to prevent the blood pooling or collecting in the large muscle groups of the lower body that are typically the muscles that have been working hard in the aerobic exercise. This blood may have trouble getting back to the heart because veins do not have smooth muscle to facilitate blood flow against gravity back to the heart. Veins have valves that stop back flow of blood however, and when these valves stop working the blood pools permanently in lower vein sections contributing to varicose veins. So, the quadriceps muscles and other muscles in the thigh have been called a "second heart pump" because their contraction puts pressure on the veins, facilitating that blood flow back to the heart. Keep moving to continue to contract the muscles until heart rate is under 120 beats per minute (bpm) or at 20 beats in a 10 second count. Stretch the working muscles after the cool-down.