Tyler Robbins Fitness

B.Sc. Biochemistry, Certified Strength and Conditioning Specialist (CSCS), Certified CrossFit Trainer (CCFT/CF-L3), USA Weightlifting Level 1

Filtering by Tag: Calculate heart rate

Heart Rate Zones

I received a question the other day that reminded me about a common misconception or thought amongst so many, especially those who may just be starting their health and fitness journey. Some things can be quite confusing, such as those "heart rate zone" charts you see plastered in nearly every gym, so I figured I would clear up some misconceptions.

For cardio exercise there various zones of heart rate and I know higher heart rate burns more calories overall but would I be better off dropping my intensity down to more of a fat burning heart rate?

I think the problem people run into, is when they see the type of "Target Heart Rate Zone" chart like the one on the right. There isn't necessarily anything wrong with the chart, however the titles for each "zone" can be a bit misleading, especially for someone who may not fully understand what each zone means.

This can be especially confusing for newcomers to the health and fitness world, those who are interested in burning body fat, so they think that keeping their heart rate at a lower pace will help them burn body fat (adipose) faster or more effectively.

Your body runs on (basically) 2 main sources of fuel: fat and sugar. Fat comes in the form of adipose tissue. Sugar comes from, well, sugar. Dietary sugars are digested and packaged into a product known as glycogen, which is stored in muscle cells for times of fast, explosive bouts of strength/power. Fat, as many of you probably know, is stored as adipose tissue at various places on our bodies.

Fat metabolism (turning body fat into energy) requires oxygen to be present for the chemical reactions to take place. This is also known as oxidation or aerobic metabolism.

Fast, short bursts of energy come from burning glycogen (muscle sugar). This chemical reaction does not need oxygen to be present in order to happen. This is known as anaerobic metabolism.

When we are doing daily activities, such as walking, climbing a few stairs, folding laundry, making dinner, etc. our heart rate stays relatively low and our breathing rate also remains quite constant and in control. This is because our bodies are primarily using aerobic metabolism to meet its energy demands. I say primarily because you may have short bursts of effort throughout your day such as picking up your child, or quickly dodging a bus on the street. In those quick bouts of energy usage, our bodies quickly use some of the stored glycogen.

We are able to keep up with the energy demands placed upon us by breathing and keeping a steady heart rate. As oxygen enters your lungs, your heart pumps the blood to the working cells, as well as removing respiration waste products (Carbon Dioxide) back to the lungs to be breathed out. As long as we can keep a quick enough heart rate and breathe fast enough, our bodies continue to keep up with energy demands through aerobic means.

As your heart rate climbs, however, your body begins to transition from aerobic metabolism to anaerobic metabolism. As you work harder and push yourself, your body physically can't breathe in enough oxygen to keep up with the demands, so that is when you begin to transition to more of an anaerobic energy source. Keep in mind that this is never a "one or the other" scenario. Our bodies are constantly producing a bit of energy from both systems, it's just that at lower heart rates, our primary energy system is aerobic, and as our heart rate soars, we transition to an anaerobic system.

Even when you are in the anaerobic zone (high heart rate), however, and you are primarily burning sugar (glycogen) as a fuel source, oxygen is still present and fat is being burned. Not only that, but as we "spend" some of our anaerobic energy credits, our bodies go into oxygen debt. Oxygen debt has to be paid back! That is why, when you physically push yourself, you then have to catch your breath afterwards. This is known as excess post-exercise oxygen consumption (EPOC).

So, are high heart rates potentially better? Well, let's say you start walking on a treadmill and walk at a brisk pace for 30 minutes. During that 30 minutes of moderate exercise, your body is burning a few calories, your heart rate is slightly elevated, and your breathing has increased a bit. This is beneficial for your cardiovascular system, don't get me wrong, but there are times when you certainly have to push yourself harder than that, especially if you wish to burn more calories. Since you are able to keep up with the energy demands by slightly elevated respiration, your slightly elevated calorie burn stops once that 30 minutes is up.

On the other hand, if you are doing highly intense exercise, perhaps in intervals (HIIT), for 30 minutes, your heart rate is going up and down. Your breathing is laboured. You have to keep fighting to catch your breath. Although the exercise session may end after 30 minutes, your heart keeps pumping at an elevated rate and your breathing stays high for a short time afterwards while your body tries to re-pay that oxygen debt. Not only that, but since you used up some of those glycogen stores, your body will now spend the next few hours trying to replenish those stores, including snatching up any dietary sugar you will be ingesting.

I think a better heart rate chart is one that explains the various zones such as the one on the right. There is definitely something to be said about various heart rate zones, especially if you are training for an aerobic event such as a 10k or half marathon. You can't sustain a high heart rate in your anaerobic zone for too long, so you need to train your aerobic zone to be more efficient so that you can not only run an entire race, but so that you can improve your pace and time as well.

Again, various heart rates are beneficial for various reasons, and elevating your heart rate for extended periods of time is great for overall health and cardiovascular fitness, but in order to burn more calories and have a quick, efficient workout, I say go hard and then go home!

Here's a quick and easy way to calculate your heart rate (grab your calculator):

220 - age = Theoretical Heart Rate Maximum (HRM)

For your targeted zones:

HRM x %

For example, I am 29 years old, so my "Hard" heart rate zone (80-90%) would be:

220 - 29 = 191 beats per minute (BPM)

191 x 0.8 = 153 (low end)

191 x 0.9 = 172 (high end)

So my "Hard" heart rate zone is between 153 - 172 BPM. That also tells me that if I push myself over 172 BPM, I am not going to be able to stay at that pace for very long.

Exercise - are you getting enough?

I read an interesting article over at CBC (Canadian Broadcasting Corporation) the other day. Although this was a Canadian study, I have a feeling the results apply to most of North America and possibly most of Western Society.

About 15 per cent of adults and fewer than 10 per cent of teens meet physical activity guidelines for health benefits, with some not really realizing what it takes to make gains, according to Statistics Canada.

Those are some scary numbers! I knew that there was a health crisis facing majority of the population, but to be honest, I didn't realize that it was this bad.

Canadian physical activity guidelines, published in 2011, recommend those aged 12 to 17 get 60 minutes of moderate to vigorous intensity physical activity daily. For adults, the guidelines recommend that adults obtain 150 minutes of
physical activity of that intensity per week, accumulated in bouts of 10 or more minutes.

So, 150 minutes of vigorous activity every week. Break that down and that works out to be 30 minutes of good, solid exercise, 5 days a week (P90X3 or Focus T25 anyone?). So how hard is vigorous exercise exactly? Well:

The guidelines say that for adults to achieve a moderate intensity, their heart rates should be within the range of 64 to 76 per cent of their maximum heart rate and between 77 to 83 per cent for vigorous intensity.

So how do I figure that out? Well, a really quick and easy way of calculating your heart rate goes like this (this is a basic method but should work for most of the population):

220 - your age = Theoretical Heart Rate Maximum (HRM)
%Heart Rate (HR) x HRM = Range Guideline

So, I will use myself as an example:

220 - 29 = 191 (HRM)
0.64 x 191 = 122 beats per minute (bpm)
0.76 x 191 = 145 bpm

0.77 x 191 = 147 bpm
0.83 x 191 = 159 bpm

So, for my, moderate exercise is when my heart rate falls between 122 - 145 beats per minute, and vigorous exercise is when my heart rate falls between 147 - 159 beats per minute. You can get heart rate monitors for relatively cheap these days, but if you don't wish to buy one, then try a couple of these tips:

  1. Stop and check your own pulse for 15 seconds during or immediately following exercise. It only takes 15 seconds so don't worry about losing momentum during your workout or anything like that. Multiply the number of beats you count by 4 to get your beats per minute.
  2. A less accurate, but still relatively useful tool is the talking test. If you can carry on a conversation with someone, you are more than likely doing "light" exercise. If you can talk, but only between breaths, then you are more than likely in the "moderate" range. And if you are breathing too heavy to speak or can only mutter a few words here and there, then you are in the "vigorous" zone.

That's it! I know, a lot of the readers of my blog are probably already hitting these goals...you are, aren't you? That is why these numbers are so scary. According to this study, only 15% of adults and 10% of teens are getting enough vigorous exercise. And according to the study, there seems to be a measurable percentage of the population who thinks they're getting enough, but simply aren't! Not only that, but make sure you are always pushing yourself,

Brown raised another potential issue. Sometimes she sees people working out at the gym doing the same exercise on the same machine at the same level each time without taking into account that they're getting fitter and need to increase the intensity to get fitter.

Remember, the more you exercise, the more your body will improve. As you improve, your cardiovascular system becomes more efficient and can complete the same level of work as before with less effort or strain. This means that even if you went for a light 1 mile jog the other day and were breathing heavy, that doesn't mean you will always will. Instead, try increasing your distance a bit or increasing your pace.