I quit writing about the ABCs of exercise years ago, after I realized nobody was listening. That, and I really don’t care too much about the ABCs of exercise anyway. People are going to do what they’re going to do – despite my experience and my desire to share my wisdoooooom. However, for those so inclined to read further, I have something which you might find a little useful this week…
As we depend more and more on electronics to track our exercise data, it’s important to understand that the information feedback isn’t always accurate when it comes to the calories/energy utilized during exercise. There are many variables at work here.
Example: My BMR (basal metabolic rate) has me burning roughly 95 calories per hour at rest. I burn a few more per hour when I am casually active, and shitload more when I am very active. However, an accurate BMR has to factor in your lean muscle mass. Online BRM calculators, and those that are connected to personal exercise devices don’t always do this. Unless you use hydrostatic weighing to calculate and factor in your lean muscle mass, your BMR will be an approximation.
Because I know what my lean body mass is, I have an accurate number for my BMR. Knowing my accurate BMR, I also have a better idea how much energy I use when engaged in running, cycling, or hill climbing. During intense cardio activities such as these, and if I maintain a heart-rate of roughly 155 bpm, I will be burning roughly 100 every 10 minutes, or 600 calories per hour, though this also depends on load, as well as the range of motion being used by my legs. But overall, I burn roughly 600 calories per hour during a hard cardio session.
The attached graphs are from two steep hill hikes I did last week, 24 hours apart. Time, distance and calories burned are noted.
The app I chose on my iPhone is a generic step counter. It doesn’t factor in my BMR so it doesn’t know how much muscle mass I have when as it calculates calories burned, which is kind of important. This app tracks distance only, and not even elevation changes. The hike I do has 800 feet of climbing on the front side, and 400 feet on the back side, for a total of 1,200 of climbing in just 4.1 miles. That’s’ a shit-ton.
Since this app does not factor in my relative muscle mass, and that the GPS mechanism does not factor in elevation changes, it calculated that I burned roughly 365 calories during two very intense 1hour+ hikes.
The reality is, based on my heart-rate and my muscle mass, that I probably burned in excess of 800 calories during each of these hikes – more than double what the app suggests.
Additionally, note that the hike of 1:15:28 showed me burning only 2 calories more for 5 minutes less over the same distance. Since my average heart-rate on the 1:15:28 was 161, and my average heart-rate on the 1:20:54 hike was 154, I probably burned 60-70 more on the shorter hike.
Now to the bike…
The app I chose doesn’t know if I’m peddling, running, or hiking. It only knows that I’m moving. The graph below is from a 10-mile bike ride which I did earlier this week. The ride was challenging to be sure, but not 930 calories worth of challenging. Again, based on my BMR and average heart-rate (145 for this ride), it was probably more like 400-450 calories of energy used, despite that the app calculated 930.
My point to all of this is that, although the GPS portion of the data provided by my app was accurate, the calorie data was based on a generic, one size fits all hominid profile. The data you get from your app will only be as solid as the data you provide about you; age, accurate BMR, heart-rate, whether or not you are running, biking, or walking, etc. Without that information, it’s probably not going to be accurate, and is likely to be quite wrong.
This is not to suggest that we don’t use electronics to track our fitness data – these can be very useful tools when used properly. But as I like to say, we have gotten by for tens of thousands of without depending on apps and devices to track our fitness. If we’re breathing hard and sweating, we’re ahead of the game. If you’re sitting still, you’re simulating death. Be well… Jhciacb
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