HEART RATE TRAINING

A perspective from this fitness professional

Those of us who enjoy educating others often create metaphors to make concepts eaiser to understand. That's why the use of the word zone, and zone training, when talking about fitness training, has become a current buzzword. It puts some structure around some basic concepts.

If you've looked at any of the new heart rate charts, you've seen the term fat burning zone or "weight management zone" to describe the pace at which your body prefers to use fat to fuel the muscles (partially true) and thus the intensity at which your most likely to lose fat as weight (not true). People who work out as hard as possible are said to be in the "red line zone". The color red infers warning because in addition to not being able to sustain this pace for a lengthy period of time, the intensity predisposes you to injury. There's currently a best selling diet book in which the author encourages you to eat 'in the zone'. Like fitness zones, it's catchy. It gets your attention. It gives you a goal. But is it right for everyone?

The Zone diet controversy can be cleared up quite quickly. You only have to look to years of research and a nutritional biochemistry book to discover that there is no rationale for the low carbohydrate 'zone' diet encouraged by the author of this book. Lose weight quickly? Perhaps. Gain it back quickly? You can count on it. As for fitness zones and zone training, the idea has some merit but like everything else in fitness, one size doesn't fit all.

Ultra racer, Sally Edwards, who has had considerable (and successful) experience using a heart rate monitor in her racing career, coined the term Heart Zone Training. It describes a series of exercise intensity levels that are relative to the maximum number of times that your heart can beat in one minute. With a maximum heart rate (MHR) as an anchor, zones in 10% increments of that number can help define more precisely what kind of benefits you'll be gaining as you move through these various intensities. Heart Zone Training is another way to provide structure to a variety of training strategies. Zone training makes use of the new heart rate charts. (See ours at the bottom of this newsletter.)

Nevertheless, there's a flaw in anchoring your workout to your maximum heart rate. Few people know what it actually is. To learn it, you need to exercise at maximum intensity (red line zone) for 30 seconds or so and record your heart rate. Exercising at this intensity is hard. It's very uncomfortable. Even highly trained athletes can't spend much time there. Exercise at 90-100% of your maximum heart rate and you significantly increase your risk of injury. I often meet athletes who are willing to take the risk to do a self test. They have usually used a heart rate monitor and have pushed themselves to their limit in an attempt to learn how high their heart rate will go. They have a good sense of the stress their body will tolerate. They're used to pain for gain. They believe the benefits outweigh the risks. They know the value of anchoring their training to a true maximum heart rate. But even for those willing to put themselves through a max heart rate test the result can vary on any given day for any number of circumstances. Maximum heart rate is affected by heat, cold, altitude, dehydration, medication, stress, poor sleep, too much to eat. It changes as activity changes. Get my drift? The heart is the king of all the muscles. Its ability to beat a maximum number of times in a minute in response to internal and external changes and to adjust the body accordingly is awesome.

In lieu of the maximum heart rate test, physiologists suggest people use an age related max heart rate to anchor their zones. You've probably been advised to exercise anywhere between 55 and 90% of your age related maximum heart rate (different 'experts' advise different percentages). At about 50-60% of your max heart rate you get sufficient health benefits to prevent many illnesses. That's why there is so much press encouraging sedentary folks to exercise at these low, less challenging levels. It's easier to convince a sedentary person that 'a little bit will do you.' It's also more likely that they'll agree and get off the couch. They may not 'see' the effects their effort is having on their body, but most admit they feel better.

At 60-70% of your maximum heart rate, in addition to changing how efficient your heart is, you begin to train your muscles. Your body needs more fuel and begins to access stored fat for fuel.. That's where folks start noticing the benefits of exercise that they rarely see in a healthy heart zone. Early in zone training, Sally Edwards named this 'zone' the fat burning, then later, the weight management zone. It's true that fat is the preferred fuel for muscles when exercising at lower intensities and that the muscles require more glucose (sugar) and less fat as that intensity increases. However, the number of calories required at exercise intensities over 70% increases the total amount of fat (and calories) burned. Once again the terms fat burning zone and weight management zone are good marketing tools to get overweight people moving beyond healthy heart zone to higher levels of exercise. There's a saying that bikinis tell a lot about a body but not the whole truth. The same is true with calling exercise intensity at 60-70% of max a fat burning or weight management zone. When I worked with Sally, I insisted that term be changed. We spent a lot of time brainstorming to come up with an appropriate name. Linda Shelton, the fitness editor of Shape magazine, joined our effort (if you'll excuse the pun). Ultimately she suggested 'temperate zone'. Like temperate weather or a temperate personality, it suggests a good place to hang out. Temperate Zone was a winner (thank you, Linda).

At 70-80% of your maximum heart, rate the body really gets tuned up. You become more than healthy. You're a performer. Your fitness level improves significantly. The heart gets really strong. You burn lots of fat for fuel. In fact, the term aerobic means air. Stored body fat requires oxygen to burn. Aerobic exercise is fat burning exercise. This is the famous target heart rate zone that we've seen on exercise charts. It's here that you see significant changes on the outside of your body that match the significant changes taking place inside your body. Endorphins, the brain's feel good chemicals, increase. Best of all, the exercise you do here creates significant after effects of your workout that make you stronger. That's why sometimes an hour after your workout in the aerobic zone you still feel warm. It's the metabolic after effects still burning fat and making you stronger and fitter.

Exercise at 80-90% of your maximum heart rate and you can feel the stress on your body. The number of calories you burn in a minute is high but that increased intensity has a price. It's discomfort and risk of injury. This is the zone that gave us the phrase 'no pain, no gain'. It's here that most fit people go from being breathless but able to talk to a friend while exercising (aerobic exercise) to an intensity where they can't talk without gasping for breath (anaerobic exercise). Most people don't enjoy exercising at this intensity. However, there are advantages to making short bouts or intervals or 'wind sprints' into this almost breathless place. Wind sprints raise the threshold (called anaerobic threshold) at which your muscles go from burning fat to not burning fat for fuel. Add half a dozen twenty second intervals or wind sprints to your 30 minute workout and in it's attempt to recover your body will perform miracles. Metabolism will change to tolerate the intensity by raising the anaerobic threshold. You'll notice it because you won't get breathless at the heart rate you did previously. If muscles burn fat in aerobic exercise, a higher anaerobic threshold means an increased ability to burn fat during exercise.

At 90-100% of your maximum heart rate you may be doing more damage to your body than you are helping it. Only very highly trained athletes or people performing maximum heart rate tests venture into this zone.

Once you know about the benefits (and liabilities) of exercising in various 'zones' which are a percentage of a maximum heart rate, it's easier to understand why folks want to know that number. It's a dangerous assessment for most people, so scientists have spent a lot of research time in an attempt to figure out alternatives to max heart rate testing. Most involve mathematical formulas. You're probably most familiar with the one that subtracts your age from 220. This is the calculation that has been posted on charts in exercise classes for years and is now used on exercise machines where you are asked to 'enter' your age in order for the machine to calculate your workout pace. Again this is flawed. There's conflicting research about the accuracy of these calculations. Those of us who work in the fitness business know many people whose age related maximum heart rate is erroneous. I know a very fit 75 year old man who works out at 170 beats per minutes without being breathless. I also know a 28 year old Olympic cross country skier whose heart rate at maximum exertion never goes above 168. So these 'formulas' are guidelines.

The good news is that you don't need a formula to design your exercise program and you don't need a reading of your maximum heart rate. You just need to know your heart rate at your anaerobic threshold. It's easy to find out with a 'talk test.' That takes a little bit of time and a willingness to exert some energy. If you have a heart rate monitor, this assessment will be easy. Here's how it works. Start walking to warm up your muscles. (I like the Reebok walking shoes best!) As you walk, attempt to monitor your pulse with periodic pulse checks (preferably using your heart rate monitor). You can also pay attention to your perceived level of exertion (sometimes called rate of perceived exertion). Here you use a scale of 1-10, then describe your pace as easy, fairly easy, medium, etc. using this range of numbers where 1 is very easy and 10 is very hard. After you are warmed up, increase your pace to an intensity where your perceived level of exertion or heart rate increases about 5 beats every 30 to 60 seconds. Pay attention to your breathing. When your pace is sufficient that you can't sing a song without taking a breath in a place where you normally wouldn't, check your heart rate. I encourage folks to have fun and learn to say Mary Poppin's phrase, supercaclifragilisticexpialidocious!! When they test for their anaerobic threshold, they know they've reached it when they can't repeat that word without taking a couple of breaths. That pace is what I call your 'functional' anaerobic threshold.

I believe knowing this 'threshold' number is much more important than knowing your max heart rate because it is the place at which your body shifts from aerobic (primarily fat burning) metabolism to anaerobic (primarily sugar burning) metabolism.

Whenever I work with a client, we determine this number and, for the purposes of designing a workout, look at a heart rate chart and find out where this number is on the 80% heart rate line. This may or may not truly be 80% of that client's maximum heart rate. But with that point as an anchor we can design a multiple zone (and multiple benefit) exercise prescription that will increase fitness and decrease fatness. We'll know we're doing wind sprints when the intensity goes above that number. Most deconditioned folks are encouraged to exercise only at 50-60% of an age predicted max heart rate. With this program they exercise just like everyone else.

There's more value to knowing this number. It's about motivation. Your heart has a resting point. It's the lowest number of beats your heart rate goes to at rest or the resting heart rate (RHR). The most accurate RHR is counted when you wake up in the morning before you sit up to get out of bed. You can get a pretty close approximation if you lie down and are still for ten minutes or so. Once you have your resting heart rate and your functional anaerobic threshold numbers, you can create a 'chart' that in relation to being dead (no heart rate at all) and your maximum heart rate (which you don't know) defines that range of exercise where the body prefers to burn fat as fuel.

(Heart Rate Chart)
With regular workouts that include 'wind sprints' above your anaerobic threshold, this number will not only go up, your resting heart rate (for most folks) will go down. If you create a graph like the one above you will be able to plot and see the changes in your fitness on a daily, weekly or monthly basis. We're talking major motivation here!!!

Heart Zone Training breaks this fat burning range and the two levels above anaerobic threshold into the zones described earlier. Believing 'you can only manage what you can measure' Edwards encourages you to spend a specific number of minutes in specific zones based on training goals. Each zone has points (1 for Healthy Heart, 2 for Temperate, etc.) which are multiplied by what she calls time in zone--the number of minutes you spend in each zone. Recording accumulated points validates your experience. It's an incarnation of Ken Cooper's point keeping system.

I believe folks with a competitive based training program or those who like specific records of their workouts will find it useful. Others will be more like me. They'll discover that a focus on all those numbers and times and record keeping takes the fun out of getting and being fit. Agreeing that I needed to work out at more than one intensity and disagreeing that it is important (or even necessary) to know my maximum heart rate, I like my alternative. It takes the best of zone training concepts and make them more usable for us regular folks. I hope you agree.

If you'd like a copy of The Heart Rate Monitor Book ($12.95) or Heart Zone Training ($10.95) call our toll free # at 1-480-242-4812.