Exercise Basic Chapter 14


Build a Better Cardiovascular System

Aerobic exercise turns your heart, lungs and blood vessels into a strong, efficient system. As you build endurance, your body adjusts, growing networks of new blood vessels to accommodate larger amounts of incoming oxygen. Your heart strengthens. Your blood pressure lowers. You're in the flow.



PART 1

The Heart

Your heart is the exercise engine, pumping oxygen-rich blood to every extremity so that your body can make fuel to keep going. With every heartbeat, the cardiac muscle forces blood out through the network of vessels. The organ becomes more efficient at this task the more you exercise.

Your heart is a muscle, and the work that it does during exercise makes it stronger. A stronger heart can pump blood with less effort than the heart of someone who hasn't exercised, which results in less pressure on your arteries with each beat—lower blood pressure. READ MORE

When you are performing aerobic exercise, you should work at an intensity that requires your heart to beat at 60% to 85% of its maximal rate, or beats per minute. There are many formulas and calculators that help determine your target heart rate, including this one: www.sparkpeople.com.

An easy, common-sense test is the talk test. While exercising, you should be able to answer a question. If you can talk easily for several sentences, you are likely not challenging your heart enough. If you must take a breath between every word, you may be exercising at too great a heart rate, which means you are working anaerobically, rather than aerobically. Adjust your speed or stride to reach that mid-range intensity. LESS
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PART 2

Building New Pathways

As your heart grows more efficient, the superhighway of blood vessels in your body has a greater load to deliver to your muscles. When more oxygen is taken in to be transported to tissues, your arteries accommodate the increased traffic by building new pathways for blood to travel. A factor called vascular endothelial growth factor, or VEGF, stimulates construction of more blood vessels to nourish the skeletal muscles. READ MORE

“The main factor that leads to stimulation of angiogenesis during exercise is a decrease in oxygen levels within the muscle fibers,” says Thomas Adair, Ph.D., professor of physiology and biophysics at the University of Mississippi Medical Center. “This low level of oxygen is called 'hypoxia.' The hypoxic muscle cells release a power growth factor called vascular endothelial growth factor (VEGF).”

Adair has conducted research showing that, in lab animals, intensive exercise results in a robust growth of skeletal muscle capillaries. The presence of VEGF can increase in a single workout, but vessel growth takes place over time. In humans, says Adair, “aerobic exercise three or more times per week is likely to stimulate significant angiogenesis, if the exercise is intensive.” The exercise must also be routine, week after week. Muscles that become sedentary lose their capillaries, says Adair. The “use it or lose it” principle strikes again! LESS
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PART 3

Deep Breath, Deep Benefits

What are the benefits of a stronger heart and more blood vessels? The more oxygen your blood vessels can speed to your tissues, the more fuel you can create and burn during exercise. Many athletes measure and track the amount of oxygen they take in to gauge how efficiently they are creating and burning fuel. This measure is called maximal oxygen intake or VO2 max (the V is for volume, the O2 is for oxygen). It can be measured with sophisticated equipment, or estimated through various physical tests. The effect of increasing VO2 max is more important than the number: Building the most efficient fuel-burning mechanism possible will enable you to work longer and harder. READ MORE

Cross-country skiers have the highest VO2 max measurements ever taken, for both men and women. Other sports that require continuous intake of oxygen include rowing and running. Heredity plays an important role. Even some well-trained athletes may have genetic limitations to the density of vessels they can build, and the amount of oxygen they can take in. The ability of the body to respond to your oxygen needs by changing its physical structure is truly amazing. So observe your breathing as you exercise, setting a steady rhythm of deep inhalations through your nose and full exhalations out. Remember not to hold your breath on exertion during anaerobic exercise. This disruption of your breathing rhythm can also cause your heart rate to spike unnecessarily. LESS
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The material on this site is for informational purposes only and is not intended as medical advice. It should not be used to diagnose or treat any medical condition. Consult a licensed medical professional for the diagnosis and treatment of all medical conditions and before starting a new diet or exercise program. If you have a medical emergency, call 911 immediately.