ENERGY SYSTEMS/CARDIOVASCULAR FITNESS

The Cardiovascular System The cardiovascular system is comprised of the heart and the vast network of blood vessels that carry blood with vital nutrients to every cell in the body. Through increased physical activity and training, we can strengthen this system, making movements (exercise) more efficient and ultimately, improving general health.

Why Is Cardiovascular Fitness So Important? Some benefits of c-v training include: reduced resting heart rate; lower blood pressure; reduced risk of heart disease; Improved metabolism; Maintains/improves body composition…less obesity, less chance of diabetes, etc. Why Is Cardiovascular Fitness So Important?

Mechanics of the Cardiovascular System RESTING HR - While resting, the heart pumps about 72 beats per minute on average. As the demand for oxygen increases with exercise, the heart must pump faster to provide more oxygen. With improved fitness, the resting heart rate DECREASES because the heart muscle gets stronger and creates a greater contraction. This forces more blood out with each beat (more efficient pump). Mechanics of the Cardiovascular System

Blood Pressure – in healthy individuals at rest, the blood is pumped through the arteries at a pressure of around 120/80 mmHg. As a person becomes more fit, this resting pressure stays near constant due to healthier vessels (more elastic vessel walls). Poor health (especially diet and inactivity) can cause the lining of the vessels to “harden” and lead to higher blood pressure at rest and with exercise.

Stroke Volume – this is the amount of blood pumped out of the heart with each beat. As c-v fitness improves, the ventricles (parts of the heart) get larger. Therefore, they hold more blood. This, plus the added force from stronger muscle with each contraction, leads to increased blood per beat when compared to the unfit heart.

Aerobic Capacity (Maximal Oxygen Consumption) – a measure of an individual’s ability to consume oxygen at the cellular level. It depends on the delivery of oxygen to the muscle through blood and the ability to take the oxygen from the capillary and turn it into muscular energy. Also called MAX VO2; (measured as milliliters of oxygen consumed per kilogram of body mass)

Energy Systems The energy we derive from food is stored in the high energy compound called GLYCOGEN. Most energy is derived from the breakdown of carbohydrates and fat. Protein is used in the building of tissue.

Anaerobic Alactic System AKA “CP-ATP” Uses creatine phosphate Requires no oxygen Yields no by-product 100% intensity, good for 10-15 seconds

Anaerobic Glycolysis Requires the break down of glucose (sugar/carbs) Requires no oxygen 80-95% intensity for 1-3 minutes Lactic acid is produced as by-product

Aerobic Pathway aka. Cellular respiration Can use carbohydrate, fat, or protein for fuel Requires oxygen, produce lots of ATP 3 minute + ….until you run out of fuel No by-products

Anaerobic Threshold Anaerobic Threshold (Lactic Acid Threshold) – the point when significant lactic acid accumulation occurs and muscle failure results. With improved c-v fitness, oxygen delivery improves, as does lactic acid tolerance. This allows a person to work at a higher intensity before reaching the threshold

Measuring Training Intensity It is generally recognized that your Target Heart Rate Training Zone should be between 60% and 85% of your maximum heart rate or HRR (see below). Where you train in that range will depend on your experience, goals and fitness level. Measuring Training Intensity

METHOD 1 (you must know this!) Calculate % of heart rate using the formula: (220-age) x _____(desired intensity) e.g. 40 year old… (220-40) x 0.6 (60 percent) = 108 METHOD 2: Uses your resting heart rate as well.

Other ways to measure Intensity 1. Breath sound/talk test 2. Rating of perceived exertion Other ways to measure Intensity

* If you can talk easily while working out… Perceived exertion of 2-4 (scale of 10) In the 100-110 beats/min range (about 50-60% max HR) * If you hear yourself breathing while working out (reached the ventilatory threshold) Perceived exertion of 5-7 In the 140-165 bpm range (about 70-85%) * If you can hear yourself breathing and can hardly talk (anaerobic threshold) Perceived exertion of 8-10 In the 165 bpm + range (85% +)

TESTS OF C-V FITNESS Submaximal tests: - Harvard step test, YMCA step test Max effort tests (predicted max VO2) Beep test, Cooper 12 min run Max VO2 tests Require oxygen and carbon dioxide analyzers TESTS OF C-V FITNESS