Kelly McPherson CFT, CPT, CES

A very common question that I get is "What is my target heart rate zone?" This is an interesting question and the answer that I give is usually not exactly what my client wants to hear.

I don't usually like to train with heart rate as a guide. It has too much variance. A person's heart rate can vary depending on what time of day it is, what time of month it is, how much sleep they have gotten, what kind of stress they are under, what activities they have done that day, what they had for breakfast, or just plain genetics. Now I am not saying that the hundreds of heart rate monitors on the market are completely worthless. I just object to using them as a sole method of gauging intensity. It is important to monitor your body's personal Rate of Perceived Exertion (RPE) scale. If you become adept at using both of these methods together, you will very likely be fairly accurate in your intensity ratings. Most of my clients are hesitant to invest in a heart rate monitor and so I use a 10 point RPE scale with the vast majority of them with great success.

Let me explain the RPE scale a bit. Simply put, on a scale of 1 to 10, 1 being the easiest and 10 being the hardest, how hard are you currently working. Let me break it out a bit.

1 - asleep
2- awake, but just starting to get moving, sitting in a car, watching tv, etc.
3 - awake and starting to move around, getting breakfast, making dinner, etc
4 - very easy movement. Maybe grocery shopping?
5 - walking briskly, getting a little warm but completely able to focus mainly on conversation
6 - Warmer still, you should be able to carry on conversation, but should be getting that really nice warm feeling all over.
7 - Even warmer, you are struggling to carry on a conversation, but can still do it.
8 - You are kicking now! You should not be able to maintain this intensity for more than 5 minutes
9 - Wow! You could go a little faster, but not much! This intensity should not be able to be maintained for more than 2 minutes.
10 - Yikes! Is someone chasing you?!? You are going absolutely as hard as you can. This intensity can not be maintained for more than 30-60 seconds.

Ironically this scale also corresponds to your heart rate percentages on your heart rate monitor. 1=10%, 2=20%, . . . 9=90%, 10=100%

Mathematically your heart rate zones are figured at roughly (220-age)X%hr = zone. For example, for a 30 year old woman to find her 70% heart rate zone would be as follows

(220-30) X .70 = 133 (low point)
(220-30) X .79 = 150 (high point)

Alright, now that we have laid the groundwork, let talk about what kind of intensity you should be working out at. This is the part that my clients don't like to hear. There is no intensity that is just right. A good exerciser will use all of the intensity levels that are safe for him/her to use at proper times for the desired results. Agh.h h h ! That sounds like a politicians answer! I'm sorry, but it's the truth.

Some people ask me, "but what about the fat burning zone? Where is that? I only want to work out in that zone." Unfortunately as you go down the scale closer to one, our bodies are generally burning a higher percentage of calories from fat than from other sources. That means that while you are asleep you are burning a higher percentage of calories from fat than you are when you are exercising. Huh? The catch point comes in that as you work up the scale, you are burning more calories overall and so are burning more total fat calories even if the percentage is lower. It's like this. Would you rather have 2% of Bill Gate's income or 50% of mine. Yes, you would be getting a higher percentage of mine, but 2% of Bill Gate's will be a much bigger number overall.

Ok, so wouldn't it be more effective to just work out at the highest intensity possible all the time? More fat burned, right? Well, sort of. Remember, our bodies cannot maintain the higher intensities for more than a minute or two. That is not much exercise. Increased fitness and fat loss is a factor of both intensity and time. That is why I like to prescribe interval training for the vast majority of my clients. Exercise at a low intensity for a couple of minutes (about a 5 or 6) and then bump it up (about an 8) for a minute or two. You get periods of that high intensity training coupled with periods of lower intensity that you can maintain for longer periods of time. The overall result? A great fat burning, fitness building workout!

I talked a bit about interval training, but is that the only kind of intensity that I should do? Absolutely not. All of the intensities are useful for something or another in our fitness goals. The exact make up of what and how much will be largely determined by your goals, fitness level and limitations. A good trainer will be able to help you design a plan to include all the levels to your ultimate advantage. Below is a breakdown of what the levels are generally used for.

1 - sleep - get lots of this
2 - almost asleep - meditation
3 - daily living - recovery from injury or major workouts
4 - daily living - recovery from injury or major workouts
5 - warm ups and cool downs
6 - easy day workouts
7 - moderate day workouts
8 - hard day workouts
9 - performance enhancing workouts - only use this level under the guidance of a professional
10 - performance enhancing workouts - only use this level under the guidance of a professional

Variety is the spice of life. Use it to make your workouts more interesting AND more effective.