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: Heart Rate

Apple Watch Week 2 - Run/Walk Tracking Accuracy

*You can read all about my Apple Watch Initial Thoughts here.*

So I have now had the watch strapped to me for just under a week. I am still learning new things here and there, but for the most part, I feel as though I have a pretty good handle on how things work, as well as the functions and limitations. So far, I have to admit, I am really enjoying the Apple Watch experience!

I have used the watch for several workouts already, including a couple of runs that were just under 5km. I will write about my experiences with the watch and how it tracks more traditional strength training at a later date, but today is all about my experiences with its run tracking abilities so far.

On my runs, I wore my iPhone in an armband on the same arm as the watch strapped to my wrist. I used the RunKeeper app, using GPS to track my distance/pace/etc. I would like to think that RunKeeper would be accurate since it is using GPS tracking, however, I have seen the app misbehave a bit in the past, so this should by no means be a clear and decisive scientific study. There will be a slight discrepancy in time simply due to not being able to start both apps at the same time. Apple has a webpage set up detailing how to Calibrate your Apple Watch, so I tried to follow the directions as well as I could. The route I took for both runs was essentially the same with only slight differences towards the end of the run. There were slight changes in elevation, but nothing crazy by any means!

Posted below is the data collected from those 2 separate runs I went on in the past few days. The top images details the data collected from the Apple Watch whereas the small images underneath represent the corresponding 

Apple Watch

Apple Watch



Apple Watch

Apple Watch



So, on the first run, there was a 0.07km, or a 1.5% difference between the Apple Watch distance and the RunKeeper distance. The second run, however, gave me a 0.12km or 2.5% difference.

Now I am by no means saying that the RunKeeper app on my iPhone is the most accurate and detailed tracking device out there, but I would at least assume that it would be a bit more accurate than just my Apple Watch alone in collecting this type of data. If you are an avid runner that lives by your distances, split times, etc., then this may be too much discrepancy between the data for your. On the other hand, if you are that serious about your running then I would guess that you are probably already using other means to collect data on your training and races.

The other notable discrepancy in data is the amount of calories burned on these runs. The RunKeeper app is estimating a 65% and 30% increase over the Apple Watch's estimation. If I was to take a guess, I would say that the Apple Watch is probably more accurate in this regard. The first run listed there, for example, pegs me at burning over 500 calories in just 4.66km of running with the RunKeeper app. That certainly isn't impossible, but seems awfully high to me considering my level of effort on that run. For those of you wondering, yes, the data that I put into the RunKeeper app, including my height, weight, age, etc. is all up-to-date.

I am actually quite impressed with how accurate the watch is already, and it still has time to improve! According to Apple, the goal is to continue to use the watch so that it is calibrated to understand your stride, so over time, it can be even more accurate in tracking your activity. I will continue to test the watch on my runs to see if this gets even more accurate over time or if this slight discrepancy in data continues to exist. Time will tell, so stay tuned!

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.

Day 352 - My Unusual Heart...

There is something I have been meaning to share with all of you for some time now, but I wasn't too sure how to approach it, so I will be as open about it as I can, and hopefully it can educate all of you.

I have been diagnosed with Atrial Flutter. I am not entirely sure what caused this, or how long I have potentially known about it. I have my own theories and hypotheses based on my own life experiences, but I will keep those to myself as they are just that, hypotheses. I will, however, give you the story of what I know up until now.

A few years ago, every one in a while, I would notice my heart doing funny things when I would be at rest. If I was sitting down, relaxed, watching tv or something, I randomly feel these 'flip-flops' with my heart, like it would skip a beat. Fine. Not a problem. They would usually be very short episodes, and I would forget about it just about as quickly as they would happen.

Around the time I was first noticing these incidences was about the time I was training for my first half marathon, so I was in some of the best shape, cardio-wise, I had ever been in, so I just figured my heart would skip a beat because my resting heart rate was so low.

The incidences began to happen a bit more frequently, but still not alarming to me. It wasn't until about a year ago now, at the start of 2012 that I decided to just casually mention it to my doctor during a physical. She checked me out, listened to my heart, explained that I may have a "pause" that can be perfectly normal, especially in healthy individuals, and sent me for some tests. I had various tests done (ECG, ultrasound, etc.) and went and saw a local heart specialist. After seeing him, I had more tests done, all the while being reassured that my "pause" was fine, safe, and normal. I took a stress test, I wore a holter monitor for two weeks, all the while still exercising and training without any problems at all.

After my test results came back, I sat down the heart specialist again, and as it turned out at the time, I was safe and healthy as could be. I learned along my travels that people's hearts are actually more abnormal than most think. I also learned a heck of a lot about the pacing and electrical work of the heart (it really is quite an amazing piece of machinery!).

All of the tests I had done have shown that my heart is healthy, there are no structural abnormalities or problems, I just seem to have this random beat every so often. In speaking with my dad, turns out, he started having similar experiences around the same age I was when I first started noticing them (27 years old). This leads me to believe that this 'thing' really is just a genetic fluke basically.

For months I went about my daily life, training, exercising, doing the things I love with 'episodes' here and there, but knowing in the back of my mind that I am safe and it is normal, helped me not worry about the problem.

However, for the past few months, my random heart "pauses" seem to have changed a bit, and I now have episodes from time to time where my heart not only "pauses" from time to time, it also skips and races a bit. It is not painful, but noticeable. It almost feels like my heart is a bowl of jelly and someone just shook the bowl. Hard to describe, but definitely a weird sensation.

I decided to go get things checked out again, so back in I went for more tests, and back in to speak with the heart specialist again. My newest round of tests has shown that I have what is known as Atrial Flutter. You can read all about atrial flutter on the linked Wiki page, but I will say that I have been reassured by the heart specialist yet again that this is actually quite a common, and safe condition, especially someone young and fit as I am.

So what does this mean for me now?

Well, naturally, I am heading for more tests in the coming weeks. Whenever you are dealing with the heart, doctors like to make sure they know everything there is to know about your heart, so that it keeps on tickin'. I will have a chest x-ray, stress test, another 72-hour holter monitor, etc. My doc even wants me to wear my holter monitor when I go for a run so that he can see what my heart function is like while exercising.

From there, I am going to take my test results and go see a specific cardiologist known as an Electrophysiologist. Basically, they are cardiologists that specialize in the internal electrical work, especially with abnormal heart rhythms. After I see the electrophysiologist, I will then update you on where and what my next steps will be.

I am scheduled to run Tough Mudder in May with my wife. I am still going ahead with this, as I have been cleared to exercise, but I will be opting-out of the electrical obstacles. When speaking with the heart specialist, he said that getting zapped at this event is not necessarily dangerous to my survival, he said that at this point in time, I should not be messing around with the electrical systems of my heart.

What else can I take from all of this?

The original heart specialist I saw has remarked time and time again how fit I am, and how much that has helped this whole situation. When I have episodes of "fluttering" with my right atria, it is possible for that section of my heart to race at a pretty high rate. Because I am fit, my heart itself has no problems taking on that kind of heart rate.

Secondly, because of my health, I am at a much lower risk of blood clotting. When I have these episodes, there is the potential for pooling blood in my heart, which can increase the risk of clotting, for older or unfit individuals.

In fact, when I have been in for my stress test, I get a good chuckle out of doing the stress test. If you have ever done a stress test before, you walk on a treadmill at increasing pace to deliberately stress your heart to a certain heart rate. Last time I was there, the test took far longer due to the fact that the test is designed for folks who aren't in as good of physical shape. The test I took, I was not allowed to run, only walk faster and faster. I actually reached a point where I could physically not walk fast enough to keep up with the pace of the treadmill...yet my heart rate had not reached the desired 175bpm or whatever I was aiming for, my heart was just too efficient!

I am still ok to exercise! I have to admit, that was one of the first things that always goes through my mind when I am in speaking with the specialist or anyone surrounding my situation. I have grown to love exercise and training so much throughout my life and I honestly can't see myself handling not exercising very well. I have been told, however, to not completely push myself to the limit (aka, Insanity) but regular exercise is fine, at least until I get everything sorted out.

So, I will still continue to train for my Tough Mudder in a few weeks. I will participate (skipping the shocking obstacles). Following Tough Mudder, however, I will most certainly be heading back to my own Body Beast concoction with just moderate cardio exercise thrown in, and will go take all of my required tests, and see the required specialists to make sure I am cleared to continue!

As always, if you have any questions regarding any of this, please let me know or comment below. You may have a question regarding feeling something similar, so it never hurts to ask, and it NEVER hurts to get things checked out, so if you have any problems, go see your doctor.

I will keep everyone updated as the rest of this story unfolds, so stay tuned!

Quote of the day:
"There is little you can learn from doing nothing."
~ Zig Ziglar

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