Aerobic Exercise
Aerobic Exercise Aerobic exercise is the stuff of life: It''s about blood and air, the two things we can''t go without for more than a few moments. If you don''t want to be so philosophical, think of it this way: Aerobic exercise is the stuff of living, because it''s also about having energy and stamina—not only to keep up an activity for long periods without fatiguing but also to keep active and healthy far into your twilight years.
Fitness fanatics sometimes toss around superlatives like "fountain of youth" when describing aerobic exercise. Such terms actually aren''t far off the mark when you consider just one significant benefit of aerobic exercise: its ability to prevent heart disease, the top killer of men in the United States. A regular program of aerobic exercise lowers blood pressure, knocks your ratio of good-versus-bad cholesterol into a healthier balance, makes the heart pump blood more forcefully, reduces body fat and can prevent diabetes. Bottom line, men between the ages of 35 and 74 who keep aerobically active have a 64 percent lower risk of suffering a first heart attack than more sedentary men, according to one large study.
Unlike weight training, which targets specific muscles or areas of the body one at a time during short, intense exercises, aerobic exercise works large muscle groups for sustained periods. (As a rule, any exercise that causes your heart to beat fast and can be sustained for more than 20 minutes is a good aerobic exercise.) "But in a sense, you''re still targeting one muscle—the heart," says Laura Gladwin, who chairs the board of certification and training for the Aerobic Fitness Association of America.
To understand why, you''ll need a basic anatomy lesson. Muscles need two ingredients to do their work—oxygen and glucose (a simple form of sugar that is the end result of the digestive process). The longer the exertion, the more muscle cells need of both. While muscles maintain small stores of fuel, they are unable to store oxygen. So it is up to your heart and lungs to deliver a steady flow of oxygen via the bloodstream. And when you exert your muscles for a long time, muscles also need extra fuel. That, too, is delivered via the bloodstream.
So where do lung and heart fitness fit in? Easy: The stronger the heart is, the more efficiently it can pump oxygen-rich blood to oxygen-hungry muscles. The more powerful your lungs are, the better they can get oxygen into the bloodstream. So the more aerobic training you do, the more you''ll fine-tune your heart and lungs, the two main engines of your body''s speed, strength and power, says Alan Mikesky, Ph.D., director of the Human Performance Lab and associate professor at Indiana University-Purdue University Indianapolis.
The trick is to keep going without working muscles so hard that their need for oxygen exceeds the ability of the lungs and heart to efficiently provide it—a task that gets easier as your conditioning improves.
What It Takes
Your ability to improve your aerobic fitness is limited by your genes and your current level of conditioning. Still, anybody can improve aerobically if they follow well-established guidelines regarding three fundamental factors.
How hard: the intensity factor. It''s critical both to work yourself hard enough to make a difference and to pace yourself. The whole idea with aerobic exercise, after all, is sustained activity. "If your oxygen demands are greater than what you can handle," says Gladwin, "you''ll have to slow down or stop to catch your breath."
Fortunately, each of us has an onboard intensity meter. Heart rate, oxygen consumption and exercise intensity all go up in direct proportion to each other when your body becomes active. Gauging your heart rate gives you a first-hand measure of how hard you''re working.
The optimal intensity level for aerobic conditioning is 70 to 85 percent of your maximal heart rate—the rate at which your heart just can''t pump any harder. Maximal heart rate tends to be fairly consistent from one person to another, although it varies with age, declining about 1 beat per year after adolescence. You can calculate your maximal heart rate by subtracting your age from 220. If you''re a 40-year-old man, that would give you a maximal heart rate of 180 beats per minute. To determine a target heart rate that''s at least 70 percent of that, you''d multiply 180 by .70, which gives you 126 beats per minute.
Remember, this is how hard your heart should pump while you exercise. To get a handle on what it feels like to work out at your target heart rate, you''ll need to take your pulse during your workout. "Don''t do it for a full minute, because your heart rate slows as you rest and it won''t be accurate," says Ben Hurley, Ph.D., director of the Exercise Science Labs at the University of Maryland, College of Health and Human Performance in College Park. He suggests taking your pulse for ten seconds, then multiplying that measure by six for the minute-long value.
Progressing by the Numbers If you''re new to aerobic exercise (or you''ve completely laid off for a few months or more), it''s wise not to start full-tilt at your target heart rate in the interests of avoiding overexertion or injury, says B. Don Franks, Ph.D., professor of kinesiology at Louisiana State University in Baton Rouge. Instead, take it one step at a time. 1. Start by walking (or running or biking) at a pace that''s easy for you, no sweating or heavy breathing necessary. Go for about 15 to 20 minutes at least three times a week, picking up the pace as it feels comfortable. For the moment, forget about your heart rate. 2. When you can comfortably walk about three miles, figure your target heart rate, the rate at which your heart should pump during exercise. If you want to skip the math, just set a pace at which you''re breathing hard but can still hold a normal conversation. Hold this pace for 20 minutes or so three days a week. Note how much distance you generally cover at this speed. 3. When you''re comfortable with your pace, set a higher distance goal and increase your mileage by 10 to 15 percent a week, keeping pace consistent. When you meet your mileage goal, work on increasing speed, keeping mileage the same. | Getting Your Body Ready Just contemplating a spin on a bike or a dash to the corner market makes your heart beat a bit faster and causes alertness hormones and brain chemicals to start churning. But your body can''t do all the preparation it needs on its own. You have to help it out. Prescription: Before, stoke the fire. Warm muscles are limber muscles, and keeping loose reduces the risk of injury and soreness. Before starting any strenuous activity, do a five-minute warm-up of walking or rhythmic limbering movements like jogging in place and shaking your arms. "It''s like a rehearsal," says Laura Gladwin, who chairs the board of certification and training for the Aerobic Fitness Association of America. "It readies the body for more vigorous movement." Hold off on stretching, which won''t benefit cold muscles. After, turn down the burner. After you''ve finished exercising, do a light cooldown activity such as walking. "You need to bring blood that has pooled in your extremities back to the heart," says Gladwin. "If you bring your body to a complete halt after vigorous activity, you could become lightheaded or even faint," she says. Now that your muscles are warmed and pliable, do some gentle stretching to improve flexibility. |
How long: the dirt on duration. As a rule, to qualify as a sustained activity, an aerobic workout should last at least 20 to 30 minutes. There''s nothing wrong with exercising for longer periods, but once you get beyond 30 to 40 minutes, you tend to decrease your intensity, which may lower the return on your time investment if your goal is to increase your cardiovascular fitness, says Dr. Hurley. "If your condition improves to the point where you can go for a longer period, it makes more sense to raise the intensity level than to draw out the exercise."
That''s the long of it. With the short of it, the story is slightly different. If you exercise for less than 20 minutes, you don''t get much aerobic benefit—unless you exercise again for a short period later in the day. Remember, the American College of Sports Medicine now suggests that if you can''t fit a 20-minute workout into your schedule, you instead exercise for, say, 5 minutes, four times a day. What''s important is that exercising in short bursts is said to confer health benefits akin to those of more lengthy aerobic workouts. But that''s different from becoming aerobically conditioned. To achieve optimal gains in your level of cardiovascular fitness, you''ll still need to exercise for a solid 20 to 30 minutes at a stretch.
How often: What''s the frequency? How many times a week must you work out in order to see improvement? This is one place where your current condition comes into play. Some studies find that if you''re so sedentary that any increase in activity would be a major improvement, significant changes in cardiovascular condition can be made with as little as one workout per week. But don''t be lulled by such extreme scenarios. For most men, the majority of research finds that getting an optimal training response—continually notching closer to peak aerobic condition—requires at least three workouts per week, says Dr. Hurley.
Here, too, it''s not necessary—or even desirable—to work out more than that. A number of studies find that training four or five times per week provides little or no benefit beyond exercising three times. "However, working out every day is okay, as long as you don''t overtrain," says Dr. Hurley.
A Man''s Armchair Guide to Aerobic Exercises No exercise is perfect. But some are more perfect than others—for you. To help you figure yours, here''s a rundown of some random pluses and minuses. Biking Hits: Wind-in-your-hair speed. Exercise doubles as transportation. Good bikes are cool. Equipment available for indoor workouts. Misses: Reason to wear Spandex. Yahoo motorists make road riding scary if not dangerous. Running Hits: Can do anywhere, anytime. Need minimal equipment. The most spiritual of exercises, if you believe the hype. Misses: Impact injuries common. Shoes must be replaced regularly. Walking Hits: Can do anywhere, anytime. Need even less equipment than running. Injuries nil. The only exercise virtually guaranteed to lengthen your life. Misses: Low on speed and action. For conditioning, you may need to pick up the pace. Cross-Country Skiing Hits: Highest calorie-burner. Works both upper and lower body. Equipment available for both outdoors and indoors. Misses: Indoor equipment hogs floor space. Outdoors, snow and skiable land required. Stair-Climbing Hits: Low-impact. Can do year-round. Misses: Dull. Step Aerobics Hits: Low-impact. Equipment simple. Misses: Annoying videos or classes generally required. Dance Aerobics Hits: Few guys—high babe ratio. Misses: Few guys—you look like a dweeb. Swimming Hits: Low-impact. Exceptional fat-burner. Doesn''t make you hot and sweaty. Misses: Pool required. |
Measuring Up
It doesn''t take long for aerobic exercise to make a difference—a fact that you''ll feel in terms of general well-being, but which you also can easily quantify. When it comes to measuring aerobic progress, again, "let your heart rate be your guide," says Dr. Hurley.
In this case, it''s not your heart rate while exercising that''s important, but your heart rate at rest. A sedentary man''s resting heart rate is high because an unconditioned heart has to work harder at all times than a conditioned one, just to keep a body alive while it''s horizontal watching ESPN. With training, your resting heart rate goes down. A middle-aged, out-of-shape man averages between 80 and 100 beats per minute, while highly conditioned endurance athletes fall more in the range of 30 to 40 beats per minute. A resting heart rate of 60 is normal for a moderately active person. Let''s say you''re at the low end of the sedentary scale, with a resting heart rate of 80. If you start a program of endurance training, that rate will drop by about one beat per minute each week. After ten weeks, your rate will drop to about 70—already halfway to levels typical of active people.
To find your resting heart rate, don''t take your pulse right before exercising: Your body knows what you''re about to do and raises your heart rate in anticipation. In fact, says Dr. Hurley, the only time you''re reliably at total rest is just after you wake up. Lie quietly before taking your pulse for a full minute.
Maintaining Your Gains
Some men make aerobic exercise one of life''s givens: It''s something they love and will always carve time for. For many of us, however, maintaining a continuous program is a challenge. That''s not necessarily bad. Don''t fall into the trap of thinking that anything less than a maximal effort is worthless. In fact, if you make mere maintenance your goal, you can get by with considerably less effort without losing anything you''ve gained.
The key to maintenance isn''t keeping up your schedule, but keeping up your intensity. Studies find that if you exercise hard, you can reduce both the frequency and duration of your workouts. For example, you could go from training six days a week to two, or from 40 minutes a day to 13, and show no decline in performance. If you back off your intensity, however, fitness levels decline significantly, even if you work out just as long and just as often.
