Estimation of calorie burn of physical activity levels

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This post is to help you figure out your calories burned by your physical activity levels. In the previous post I talked mainly about how to figure out your Resting Metabolic Rate (RMR). With your RMR in hand you next need to estimate, as accurately as possible, your Physical Activity or your Voluntary Metabolism (VM).

Your VM is divided into 2 parts, both equally difficult to quantify exactly, but worth the effort if you want to actually lose weight. The 2 parts I define as:

  • Passive: This is your Daily Activity Levels (DAL); This includes walking, climbing stairs, going shopping, doing housework and yes even at your computer typing a blog entry. This is hard to estimate but there is data on this.
  • Active: This is when you choose to exercise, regardless activity. You could go for a run, lift weights or take an aerobics class. Whatever it is, it is possible to estimate how much you can burn. I will tell you it is easier to calculate cardio than weights.

Now just because this is difficult to do, doesn't mean you shouldn't do it. We all know that what gets measured gets done. It is better to base your planning on inaccurate data than no data at all. Throwing things against a wall and hoping something sticks is a horrible way to plan your weight loss. With weekly tracking of your weight and activities, you can tweak the numbers you until you get results. Three major factors that influence calories burned are your weight, gender and the intensity level of the activity. The more you weigh the more calories you burn during exercise, which is good news if you are overweight. The intensity level is the biggest variable with higher intensity activities burning more calories. Do note there is also a difference by gender. So any calculation or online calculator you use should include these variables. Let's break this down.

Estimating your Passive VM

Now while there are databases on calorie burn for common activities,(I've been playing around with this one at CalorieLabs) For this method to work, you essentially have to keep a journal logging all your activities and time spent and then figure out how many calories based on that. This is extremely tedious and time consuming, so I don't recommend this if you don't want to spend an hour a day doing this. (I only did it for one day and it sucked). Enter the hack.

I like to use my fitness  tracker, and use the number for daily steps. If you remember I did give you some advice to acquire one and use it. Alternatively you can use your smart phone, either Apple Health or Google Fit, which uses your phone accelerometer to measure steps. Do note you have to keep your phone in your pocket at all times for more accuracy, which can be a pain. So get a fitness tracker already. 

For me I have a 10,000 steps per day goal, which I achieve 95% of the time. From my research, I have pegged this at about 400 calories per day based on moderate activity levels. 

Estimating your Active VM

There is a lot more data on exercise so all you really need to do is keep track of your workout sessions and estimate accordingly. This is best to do on a weekly basis, broken down by day. Then calculate it back based on your actual Active VM for any given day, in case you skip a workout (try not to) or you chose to add some more exercise. This will ensure that your VM calculation is accurate for that day and allow you to plan your calorie intake accordingly.

Cardio

The easiest to calculate is Cardio as there are many tools to help you. I personally use MyFitnessPal as I also use it to calculate my food intake. You simply choose what exercise you did at the estimated intensity (or actual intensity if you are using a running tracker or something) and It will add it for you. Here are some common activities and their approximate calories burned. Its based on a 75kg male for 30 minutes duration.

  • Walking: 150 calories
  • Jogging: 263 calories
  • skipping: 263
  • Cycling: 225 calories
  • Swimming: 263 calories
  • Aerobics: 263 calories

It is important that any calorie expended calculation takes into account your own personal weight, sex, and intensity. These are just averages. The number of calories burned is mostly affected by intensity, so if you go all out you should expect to burn more calories in any given session.

Weight training

To estimate the calorie burn from resistance (weight) training is a bit harder and in exact. The principle of intensity and your lean muscle mass are the two biggest factors. So the harder you workout and the bigger your muscles the more calories expended.

You can use this formula to estimate your expenditure. Unfortunately I can only give it to you in pounds (american), so 1kg equals to 2.2 pounds. I usually just convert my weight to pounds to use this.

Weight Training Burn = (your weight in pounds x duration in minutes) x Intensity Level

For the intensity level you would use these values:

  1. Bodybuilding  = 0.055
  2. Circuit training with weights = 0.042
  3. Strength training = 0.039
  4. Light lifting with moderate effort = 0.028

For the duration you include rest time between sets not just time under tension.

I'll show you how this works for me for a 30 minute session of strength training:

My weight = 75kg x 2.2 = 165 pounds

Weight Training Burn = (165 x 30) x 0.039

Weight Training Burn = 193 calories burned

Now that we can figure out our calories burned we can then move on to figuring out our week and specifics.

So how does this look like for me?

I do 3 main activities per week on 6 different days, and calculate burn based on intensity. Some of these are pure estimates based on research so I assume there is around a 20% margin of error. I would break my week down as follows: 

Monday: 2 hour Muay Thai training: 

  • 15 minutes stretching = 50 calories
  • 25 minutes skipping = 250 calories
  • 1.5 hours bag and pad work = 540 calories
  • Total = 840 calories

Tuesday: 1.5 hours Strength and Conditioning 

  • 20 minute warmup (1 km run, circuit callisthenics) = 150 calories
  • 30 minutes heavy compound lifts = 193 calories
  • 30 minutes power and functional training = 208 calories
  • 10 minute cool down - not included
  • Total = 551 calories

Wednesday: 2 Hour Muay Thai training = 840 calories

Thursday: Strength and Conditioning = 551 calories

Friday: Road work

  • 30 minute steady state jogging = 409
  • 10 minutes stair sprint intervals = 186
  • Total = 595 calories

Saturday: Rest

Sunday: Road work  = 595 calories

Total Weekly Calorie Burn from VM = 3972 calories

 

Putting it all together

So now lets say I want to calculate my total calories expended for a Monday:

Calories out = RMR + Passive VM + Active VM

Calories out = 1715 + 400 + 840

Calories out = 2955 calories

 

So you see I can now know with a reasonable degree of certainty that I will expend 2955 calories on a typical Monday. Armed with this knowledge, I can then begin to plan out my diet t0 figure out my personal Energy Balance Equation. That is the next step and the subject of the next post.

Got a question? Got a comment? Let me know, I am happy to answer. Hit me up.

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