Chapter 8 - Cardiorespiratory Training Flashcards
Cardiovascular System
Cardiovascular or circulatory system is a closed loop system composed of the heart, blood vessels, and blood. Blood travels through the heart to arteries, capillaries, veins and back to the heart.
Blood - Plasma & Non-plasma
The liquid portion of the blood which carries hormones, proteins, food materials, ions, and gases throughout the body. The non-plasma part of blood are the formed elements: red blood cells, white blood cells and platelets. Bloods primary function is transportation. Other functions are temp regulation and acid/base balance.
Arteriosclerosis definition
Hardening of the arteries and narrowing of the arteries due to plaque accumulation
The heart
Size of a human fist.
Right 2 chambers for pulmonary circulation (atrium/ventricle), receives depleted blood
Left 2 chambers for systemic circulation (atrium/ventricle) receives oxygenated blood
Respiratory System
Provides a means to replace oxygen and remove carbon dioxide from the blood. It makes speech possible. Helps regulate acid/base balance during exercise. Comprised of nose, nasal cavity, pharynx, larynx, trachea, bronchi and lungs. Passages that filter air and transport it into the lungs where gas exchange occurs within alveoli. 300 million alveoli!
Oxygen carrying capacity of blood is determined by:
- Ability to ventilate the alveoli in the lungs
- Hemoglobin concentration in the blood
In most healthy individuals the oxygen carrying capacity of the blood is not a limiting factor in the performance of cardiorespiratory exercise.
Pulmonary ventilation is a function of:
Rate and depth (tidal volume) of breathing
Oxygen Delivery
Most important factor in cardio fitness is delivery of 1) more blood to active cells (muscles) which is a function of cardiac output and 2) less blood to inactive cells (digestion)
Cardiac Output Formula
Cardiac Output = Heart Rate (HR) BPM x Stroke Volume (SV) in liters
Cardiac Output Volumes
At rest typical cardiac volume is 5 liters/min.
During maximal exercise this increases to 20-25 liters/min
Can reach 30-40 liters/min for highly trained person
SV can increase 40-50% and then plateaus
Oxygen Extraction
The amount of oxygen extracted is largely a function of muscle fiber type and the availability of specialized oxidative enzymes. (slow twitch muscles are adapted to oxygen extraction due to high levels of oxidative enzymes)
Adaptation to Training (oxygen exchange)
One of the most important adaptions to training is an increase in the number and size of the mitochondria with a corresponding increase in the levels of oxidative enzymes used to aerobically produce ATP
First Ventilatory Threshold (VT1)
Intensity of aerobic exercise at which ventilation starts to increase in a nonlinear fashion in response to an accumulation of metabolic by-products in the blood.
Second Ventilatory Threshold (VT2)
A metabolic marker that represents the point at which high intensity exercise can no longer be sustained due to an accumulation of lactate.
Low Intensity Exercise Adaptations
- Involves Type 1 muscle fibers (slow twitch)
- Increases size and quantity of mitochondria which aids ATP production
- Growth of more capillaries around the recruited muscle fibers which enhances delivery of oxygenated blood
- At upper limit of muscle capacity to generate force there may be contractile adaptations leading to hypertrophy. (actin and myocin filaments)
High Intensity Exercise Adaptions
- Involves Type 2 muscle fibers (fast twitch)
- Increase in the number of anaerobic enzymes so that anaerobic energy production is enhanced
- Contractile proteins may increase resulting in hypertrophy
Adaptations of Respiratory System
Muscles of the respiratory system will adapt as exercise is performed regularly to allow for increased ventilation of the alveoli, which is where the respiratory system interfaces with the cardiovascular system.
Cardio Adaptation Time Required
- begins with first exercise but usually takes about 2 weeks before readily measurable
- Maximal Oxygen Uptake (VO2 max) increases with training but plateaus and peaks at about 6 months of training.
- Ventilatory threshold may adapt for years. It is a significant marker of metabolism that permits prediction of lactate threshold during progressive exercise. (due to capillary growth and increased mitochondria density)