Age-Defying Fitness: Aerobic, or Endurance Exercise

Summarized by Robert W. Griffith, MD
May 31, 2007

Marilyn Moffat and Carole Lewis are physical therapists who have been in private practice for a number of years. They have both published and lectured extensively, and have written "Age-Defying Fitness" based on their experience with their aging patients. Their aim is to inspire and motivate readers to do something good and long-lasting for themselves: exercise. We are pleased to post several extracts from their book. Here is the fifth. Robert Griffith, Editor.

Endurance

"You have to run faster and faster just to stay in the same place!"

Lewis Carroll

Endurance is a combination of aerobic capacity, cardiopulmonary performance, and stamina. Whether you are running a marathon, walking the dog, or learning to use a new walker - and whether you're 29, 59, or 89 - endurance enables you to do what you want to do for as long as you want to do it. The bad news is that as you age, you must work harder to maintain your level of fitness. The good news is that you can improve your capacity every day. Raising your endurance levels will provide you with the stamina and vitality you need to develop your pos¬ture, strength, balance, and flexibility.

Phil, 52, was quite an athlete in high school. The first time he came up to bat in his law firm's softball game, he hit one out of the park. That crack of the bat felt great! He didn't feel so great, how¬ever, after running the bases. He couldn't believe how out of breath he was when he crossed home plate.

Proper Endurance

Endurance is the body's ability to sustain an activity over a period of time. There are 2 basic types: muscular and cardiovascular.

Muscular endurance allows you to perform any activity that requires repeated muscle contractions, such as climbing 3 flights of stairs. It is best achieved through strength training with increased numbers of repetitions, such as the exercises in our chapter on Strength Training.

Cardiovascular endurance allows you to walk, run, jump rope, swim, or perform any other activity that uses large body muscles (such as those in the front of the thigh and the buttocks) over a prolonged period. Healthy cardiovascular endurance enables your lungs, heart, and circulatory system to function efficiently so that you don't develop shortness of breath or excessive fatigue.

Some activities require both cardiovascular and muscular endurance. Your lungs, heart, and circulatory system must function efficiently to comfortably climb 3 flights of stairs, but so must your leg muscles.

If you have any coronary artery disease risk factors, we recommend that you seek the guidance of your physician before you start any conditioning program. Here are the commonest risk factors for coronary artery disease.

Modifiable Risk Factors (those you can control)

• High blood pressure
• High cholesterol levels
• Good cholesterol/bad cholesterol ratio
• High triglyceride levels
• Smoking, second-hand smoke
• Obesity
• High stress level
• Sedentary lifestyle
• High blood sugar levels/diabetes
• Diet
• Poor education about heart health

Non-Modifiable Risk Factors (those you cannot control)

• Age (men over age 45, women over age 55)
• Race (whites have a greater risk)
• Gender (men are at higher risk until age 70, when risk evens out)
• Family history of heart disease
• Fibrinogen levels in blood
• Enlargement of left ventricle
• Previous heart attack
• History of heart valve or peripheral vascular problems

Checking Your Heart Rate

This chapter focuses on improving your cardiovascular endurance. To accomplish this, you need to know how to check your heart rate, and then how to set your target heart rate.

This is the most accurate way to check your resting heart rate: on 4 con¬secutive mornings, before you get out of bed, count the number of times your heart beats in one full minute. The best way to do this is to take your radial pulse at your wrist artery. Place your right index and middle fingers against the inside of your left wrist just below the base of your thumb. Press gently; if you press too firmly you might not get an accurate reading. After recording your resting heart rate for 4 consecutive morn¬ings, calculate the average of the 4 readings. A resting heart rate is usually between 60 to 80 beats per minute (BPM), although a rate of 60 to 100 beats per minute is considered normal.

Once you are proficient at finding and counting your pulse, you can use a shortcut. Count your heart rate for 10 seconds and multiply the number by 6. This gives you your heart rate for 1 minute.

Before you begin exercising, relax in a chair for one minute, and then take your resting heart rate. You are now ready to monitor your heart rate while exercising aerobically.

To see how activity affects your heart rate, take your resting heart rate and then jump or run in place for 2 minutes. Take your pulse immediately afterward. Depending on your aerobic condition, your pulse should rise anywhere from a few beats to more than 20 beats per minute. Continue to exercise for the next 10 minutes, taking your pulse every 2 minutes. Your heart rate should return to its resting level 2 to 20 minutes after you've fin¬ished the exercise.

You should check your pulse before, during, and after any endurance exercise. Keep a log and record your heart rate at least once a week; you should be able not only to see an improvement in your heart's ability to recover, but also to chart the increase in your aerobic capacity, or cardiovascular endurance.

Determine Your Target Heart Rate

There are mathematical formulae for calculating your target heart rate (THR) that takes into account your resting heart rate and your age. The math is done for you on this page (just click): http://www.healthandage.com/Home/gm=4!gk=122. If you are in a hurry, use this table as a rough guide:

Age	Desired Range for Heart
40	126-153
50	119-145
60	112-136
70	105-128
80	98-119
90	91-111
100	84-102

Caution: If you take medication that alters your heart rate or blood pressure (such as vasodilators, calcium channel blockers, angiotensin-converting enzyme inhibitors, and alpha and beta-adrenergic blockers), or if you have a pacemaker, an irregular heart rhythm (atrial fibrillation), or any other condition that affects your pulse rate, do not use the target heart rate method to make decisions about your endurance training. Your heart rate is a reflection of how hard your body works. Because these medications and conditions can slow your heart rate, you might not be able to reach the heart rate derived from the target heart rate calculation; if you try to do so, you may end up overexerting yourself.

Endurance Changes

Your cardiopulmonary capacity is significantly reduced as a result of a combination of age-related changes and little or no exercise. Starting in the mid-twenties, cardiovascular system fitness declines by about 8% per decade for inactive adults and about 4% per decade for physically active adults. As you age, your maximum heart rate declines. Your heart's ability to pump blood and use oxygen efficiently is lower both when you are at rest and when you exercise, and your blood pressure at rest is higher.

The loss of elasticity in the aorta (the large artery that carries blood from the heart), leads to a 1% decrease in the output of the heart each year. A loss of elasticity may also occur in the peripheral arteries and veins. Varicose veins and a rise in blood pressure (at the rate of about 1% per year) may develop as a result of these changes. Degenerative changes in heart valves may also contribute to high blood pressure, irregular heart rhythms, a decrease in maximum heart rate, and some¬times the presence of heart murmurs.

As you age, you may develop orthostatic hypotension, a drop in blood pressure that occurs when you move from lying to sitting or sitting to standing. This can lead to dizziness or light-headedness.

The pulmonary system also undergoes changes related to aging. Lung tissue stiffens and loses elasticity; as a result, your lungs operate less effectively, requiring you to breathe more frequently. You may become more susceptible to respiratory problems. There may be spinal degeneration leading to a loss of height, rounding of the upper back, and a loss of rib cage flexibility. These changes also can make breathing less efficient and may cause shortness of breath. If you combine these age- related changes with a lifetime of little or no exercise, you will experience a significant reduction in lung capacity.

After this introduction, the chapter goes on to sections dealing with assessment of your endurance fitness, followed by 8 great exercises based on walking, cycling, skipping, water aerobics, stepping, skiing, rowing, and circuit programs.

The next, and final extract from "Age-Defying Fitness" will discuss "putting it all together".

You can buy "Age-Defying Fitness" from Amazon or from Peachtree Publishers.

Source

• Age-Defying Fitness: Making the most of your body for the rest of your life. M. Moffat, CB. Lewis, 1st edition. Peachtree Publishers, Atlanta, 2006

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