The Aerobic zone gives you the most “bang for your buck.” Here you’ll get the most benefits in the least amount of time. If you said, “I want everything from exercise,” this is your zone. The Z3 Aerobic zone gets you fitter, gets you faster, gets you thinner. That’s why it’s been touted for decades as the guts of the one mythical “target zone.” The Aerobic zone might be called the heart of the heart of it.
The word “aerobic” itself has been the hallmark of the fitness revolution which began in the late 1960s with the launch of Ken Cooper’s legendary book Aerobics. Following right behind him were the other icons that drove the principle of aerobic fitness to the forefront. Women should take most of the credit for turning the theory of aerobics into practice – what we all now know as the “aerobic class.” Star ng with Jackie Sorenson, aerobic dance guru, dance exercise leaders have taught classes in their homes, schools, company cafeterias, and of course, health clubs. Credit should go, too, to Judi Shepherd Misset, who created Jazzercise.
Simultaneously, the running craze struck, and America started jogging. Jim Fixx’s Complete Book of Running emerged as an unlikely hit and landed, feet- first, on the best-sellers’ list. Jump forward into the digital age of the 90s. It’s the era of machine exercising and digital readouts – stair climbers, spin bikes, cross conditioning machines, and recumbent bikes. It’s the heyday of cross-training and adventures in the outdoors: quadrathlons, hiking, canoeing, ultra-distance events, and power-walking. But there are plenty of fans of the new wave of indoor sports: step aerobics, heart aerobics, lateral slide training, boxerobics, and personal training.
You have now arrived at the web-apps age of the 2010’s. The 21st century, and the faster-lifestyles that got even faster as we spin like a dervish from emotional, physical, environmental, and financial crisis to the planet and all of its inhabitants. Wars on obesity, terrorism, and sedentary lifestyles make heroes out of ordinary villains. The interests of fitness enthusiasts grow with new technologies like the Wii system, digital TVs connected to every cardio-machine at the health club, and fitness competitions from reality TV weight loss shows to web-racing. Smart fabrics make sensing physiological responses even easier and more non- intrusive with blood pressure, heart rate, sweat rate, body position and temperature more readily available. And, all of the entertainment and data in the world is being connected with social networking and web 2.0 technologies and devices.
Wondering which marvelous activity to turn to? Choose any of them, and do as many of the indoor and outdoor sports as your fun-loving inner child desires; just remember it’s the zones (and the amount of me you spend in them) that matter.
THE TRANSITION ZONE
The Aerobic zone has very specific parameters. The aerobic zone floor is 70% of your maximum heart rate and it is at this point that you begin to realize substantial cardiovascular benefits. If your true maximum heart rate were tested at 200 bpm, then the aerobic floor heart rate for your purposes would be 140 bpm.
Its neighboring zone to the lower side is the Temperate zone. Once you cross over from the Temperate to the Aerobic zone, it doesn’t mean that you stop burning fat as a source of calories. It just means that the percentage of types of fuels burned changes. No longer are you burning the vast majority of your calories from fats; instead you’re shifting into the zones that use more carbohydrates as their fuel source.
The ceiling for the Aerobic zone is 80% of your maximum heart rate. This is actually quite strenuous for the novice exerciser. For someone who has been training for a few weeks or months, this might be considered “somewhat hard” or “hard” if you were to give the feeling a verbal description. Above the ceiling of the Aerobic zone is the Threshold zone. When you cross this line you’ve entered the world of performance training. If your true maximum heart rate were tested at 200 bpm, then your aerobic ceiling heart rate would be 160 bpm. This Aerobic heart rate zone is also known as the “talk test zone” because it is within this zone that you can speak without a shortness of breath or loss of words; if you start to exercise above it, however, a friendly chat soon becomes the last thing on your mind.
The Aerobic zone is the fitness area at the heart of the wellness continuum. It is the transition zone between the two health zones and the two performance zones. It’s also the first of the zones where performance training effects begin. In the Aerobic zone you begin to realize the changes that lead to athletic conditioning versus basic health and fitness. That is, this is the zone where tremendous (but somewhat technical) physiological changes occur. As indicated below, the cardio- pulmonary changes from rest to the aerobic level are enormous.
The changes are incredible – it’s a comfort zone. (Don’t forget – it’s also comfortable.) The Aerobic zone is where you break sweat, raising your core temperature to just above the sweat point, but not much beyond.
You feel like you have had a workout when you train here, but you don’t feel any of the burn or the pain. If you do, you have pushed yourself through the Aerobic ceiling and into the Threshold zone, which isn’t the place to be if your goal is to achieve fitness. It feels great to take a shower after an Aerobic zone workout because you can feel that you have released both emotionally and physically some of your stored-up toxins. The Aerobic zone is a place where you get a lot of rewards and feel good about both your mental and your physical muscles. Quite simply, when you are an active exerciser, the Aerobic zone is the place to spend some of your most memorable workouts. It’s a training zone that enhances the features of most of the other zones, and it’s a wonderful place to be.
AEROBIC PERFORMANCE TRAINING
Now, even though we just said that the Aerobic zone is in the fitness, not performance area of the wellness continuum, ironically enough, for the performance-oriented individual, the Aerobic zone is where you want to spend the bulk of your workout me. Time spent training in the Aerobic zone is called “base work me” or just “base.” The Aerobic zone is really the comfortable center to your performance training program. Training in the zones below the Aerobic zone provides little measurable effect on performance, but may add to your training stresses. Training above the Aerobic zone causes excessive dependence on glycogen and not fatty acid metabolization. For athletes, the Aerobic zone provides enough of a stimulus to improve joint and tendon strength, but without excessive stress impact. It is a zone that teaches the metabolic pathways to spare carbohydrates and metabolize fatty acids. Exercising in Zone 3 leads to other cardiac and pulmonary changes but typically does not result in over-training.
For those returning to performance training after a lay-off or injury, the Aerobic zone is ideal because it provides an adequate training load to drive the training effect from adaptation mechanisms, yet it is gentle and fun. Quite simply, it is an endurance-building zone. Training a certain amount of me in Z3 builds resistance to fatigue and increases cardiovascular efficiency.
The Aerobic zone is the place where enhancements to the functional capacity of the heart, lungs, vascular and skeletal systems really occur. Maybe that is why the Aerobic zone is also the one loved by so many exercise purists. Maybe it’s because of the mood-altering endorphins that become so profuse when training in the Z3 and Z4 zones. Discovered in the 1970s, the blood level concentrations of these opiate-like stress reducers can increase up to five-fold from the resting state as a result of exercise. Labeled the “exercise high,” this state of euphoria, which arises particularly in these two zones, can result in mood improvement and is implicated in increased pain tolerance, reduction in anxiety, tension, stress, and improved appetite control. The beauty is these benefits continue for hours after you’ve worked out.
Endorphins are still highly controversial because of limited and varying research data. It seems that the higher the exercise heart rate levels,
the greater the production or sensitivity to endorphins. That’s one of the reasons the Aerobic and Threshold zones can become addictive.
Compounding this increase in quantity of endorphins from brief bouts of higher intensity training is the slower rate of disposal of endorphins in trained individuals compared to the untrained. This slower rate of disposal allows for the effects to linger and might increase one’s tolerance for high-intensity extended training. Clearly, all of the results are not in yet.
Remember, though, that the benefits of zones are not cumulative. You have to train in a specific zone to get its specific benefit. If you are a Z3 junkie, but you really need to maximize your fat loss, you’re going to have to slow down some times to do fat burning zone (Z1-Z2) workouts. Or, if you really need to improve your 10K run me, you’re going to have to occasionally ease yourself out of the smooth comfort of the Aerobic zone, and into something a li le more challenging, say Z4. But on the other hand, if you haven’t spent much me here because you love one of the other four zones, it’s me to try Z3. Once you’ve gotten sufficiently fit, the Aerobic zone is a great place to spend gobs of time and live it up.
If you were shocked at the amount of unfamiliar exercise terminology before, you’d better steel yourself, because it gets worse before it gets better. Once you enter the fitness and performance zones, you start hearing people toss around long and impressive words, like “cardiovascular” or “cardiopulmonary,” or short and weird ones, like “VO2 max” (but more on that later).
Taking the roots of the first word, “cardio” for heart and “vascular,” referring to your blood vessels, this is the zone that works the heart and its blood-transport system. The Aerobic zone gives us cardiopulmonary – referring to both the heart and the lungs – benefits, too. In reality, all three parts – heart and lung and vessels – are simultaneously worked by the wonderful Aerobic zone.
How many actually know what “aerobic” means? Well, literally, “aerobic” means “with air.” In fitness terms, it means that you are exercising at an intensity level such that the lungs can infuse sufficient oxygen into the blood, while the heart can pump sufficient quantities of the oxygen-laden blood to all of the muscles – including the heart muscle.
Some of the cardiovascular improvements that your body undergoes as a result of Aerobic zone exercise are:
• increase in the number of blood vessels,
• increase in the size of blood vessels,
• increase in blood delivery to your muscles,
• increase in oxygen delivery to the muscles for fuel,
• increase in the oxygen delivery to the fat cells to free them into the blood,
• increase in the blood to carry the fat from fat cells to the muscles,
• increase number of mitochondria within muscle cells that convert fuels for muscle combustion,
• increase in size of each individual mitochondria,
• increase in number of capillaries in the working muscles,
• increase in size of existing capillaries,
• increase in size of coronary arteries,
• reduction in blood pressure.
An increase in both the size and strength of the heart, resulting in increased stroke volume (the amount of blood pumped with each heart-beat),
• increase in cardiac output (stroke volume times heart rate),
• decreased heart rate for the same intensity level training load.
• increase in red blood cell volume, plasma volume, and total blood volume.
Some of the cardiopulmonary or respiratory changes that result from training in the Aerobic zone are:
• Increased vital capacity (the amount of air that can be breathed out after a maximal intake of breath).
• Decreased respiratory rate (the number of breaths you take in response to a given level of training load).
• Increased maximal pulmonary ventilation (the volume of oxygen per minute you can breathe).
• Increased pulmonary diffusion (the amount of oxygen exchanged by the lungs).
• Increased difference in arterial-venous oxygen (more oxygen is extracted at the tissue level).
Another value of the Aerobic zone is that if you train in Z3 your VO2 max improves. This rather cryptic benefit may not mean much to you if you are unfamiliar with fitness jargon, so let me explain. The more oxygen that you absorb and feed to your muscles, the better you will be able to exercise. With increased oxygen utlization at a given intensity level, your heart rate at that training load will be lower. Why? Your heart rate increases to provide more oxygenated blood to your muscles, but if you’ve trained your body to the point where it’s already circulating more oxygen, your heart isn’t going to need to work harder. That is a key definition of aerobic fitness improvement, and it is one of the primary benefits of the Aerobic zone.
Exercise scientists have devised a way of measuring the quantity of oxygen that your muscles burn and the quantity of carbon dioxide that they release as one of the by-products of exercise metabolism. This is called VO2 or volume of oxygen. It is quoted as a percentage of your maximum amount or your VO2 max. The average middle-aged unfit, sedentary woman’s VO2 max is about 30-40 milliliters of oxygen per kilogram of body weight, and a sedentary man’s is about 45-55 milliliters. The reason that men’s numbers are higher than women’s is because typically men have more muscle mass as a percentage of their total body weight. The larger muscle mass uses more oxygen because muscle is active oxygen-demanding tissue. The larger the fat mass the less oxy- gen used because fat is inactive tissue. For a woman with equal muscle and fat tissue percentages as a same-size male, the differences would not be great.
As you travel up through the heart rate zones, there is a continual shift in the percentages of different fuels burned. As you transition into the Aerobic zone, you are for the first time utilizing a higher percentage of carbohydrates than fats as a source of muscle fuel. This has several effects on your performance.
First, we don’t have as many carbohydrate calories in storage as we have of fat, because while our bodies may have plenty of fat cells, there are no such things as handy, quick-access, calorie-storing carbo- hydrate cells. We can only store a limited supply of carbohydrates in our muscles, blood, and liver in the form of glycogen. So, there is a limited supply of quick-energy carbohydrates stored within the body and a limitation on how much we can get out of our gut from foods that we consume while we exercise. The average person’s body contains between 375 and 475 grams of carbohydrates at any given me. Since one gram of carbohydrates equals four calories, if you multiply 375 grams times four and 475 grams times four, you know that the average person carries on board a supply of about 1,500 to 1,900 calories of glycogen. For example, if you burn 13 calories per minute in the Aerobic zone, then you would have about 2 hours of workout me available. That, of course, is if you burned only pure muscle glucose, which we don’t. Our bodies always burn some sort of blend of fat and carbohydrates together, which is why we can exercise longer than 2 hours, without having to refuel. But, the body’s increasing need for carbohydrates over fats at ever higher exercise intensity levels is why it is important to consume carbohydrates during Z4 and Z5 or very long Z3 workouts.
The quantity of carbohydrates stored in your body is dependent to a great deal on your diet. If, for example, you ate a low-carbohydrate diet or even worse, you fasted, when you started to work out there would be a huge drop in the amount of stored glycogen in your blood, muscles, and liver. This would limit your ability to train in the Aerobic zone and your overall energy level. The opposite is also true. If you eat a high carbohydrate diet you can store more glycogen on board and hence have more available to fuel you through the Aerobic zone.
One of the best, most reliable Aerobic zone workouts we’ve found is Step Aerobics. With this kind of workout, you use your heart rate to determine the height of the step, selecting a height that allows you to complete a steady-state 20-minute step training session all within the Aerobic zone.
It will take you several training sessions to achieve the best combination of step height and music cadence to get your steady-state Aerobic workout. This is because of the effects of heart rate drift, which means that at the same training load, over the dura on of a workout, your heart rate gradually drifts upwards. The same happens with your respiration rate, which drifts to a progressively increasing number of breaths per minute with any steady-state exercise.
Start with your favorite workout tape or your favorite instructor’s class and only put one riser on your step (which should make the step approximately 4” tall). For the next twenty minutes, exercise at this intensity level (one riser and at a fixed number of beats per minute for the music) and watch your heart rate change. Throughout the entire me you should be above your Aerobic zone floor yet never break through the Aerobic ceiling.
At the second session, keep the music intensity the same but add one more riser, making your step 8”. Now, determine the heart rate cost of adding that 4 inches of step height. For most, this equates to a 5–10 beat increase in average heart rate (if you have a heart rate monitor, measure the difference in the average as well as the high and low heart rate values). If it results in an increase of more than an average of 15- 25 beats per minute, this is a clear indication that your current fitness level could use some improving. It also means that you should take the second riser off and go back to a lower step level in order to stay in your Aerobic zone.
On the third exercise session if you haven’t already gone through
the Aerobic ceiling, add the final riser, which should make your step
12”, while keeping the choreography and the music identical. The only change will be in your step height. Again, measure your change in heart rate and adjust your step height accordingly for next me. After three sessions, you should have a pretty good idea of which step height gave you the best Aerobic zone workout, but keep in mind that as your fitness increases, you’ll need to start adding steps again, and retesting yourself.
Variations of this workout include mixing the choreography as well as the music cadence. Play with these variables and teach yourself how to change your zones (perhaps working through both your Z2 and Z3 zones in one workout) by varying the elements of your training load – music beat, resistance as step height, and choreography – to enjoy multiple training effects.
More to come ..
Keep your eyes peeled as we continue to release excerpts throughout upcoming weeks. If you want to read the entire book, make sure to swing by our online store and grab a copy: The Heart Rate Monitor Guidebook.