Back to Basics Part Two: How Exercise Fits In

Last week, we talked about how your nutrition affects your weight. There are websites where you can automatically calculate these numbers, but sometimes it’s important to understand the basics. In summary, this is where we were:

Exercise
So remember how last week, I gave a breakdown of how calories are processed? How does exercise fit in? Your body simply uses more of that energy you consumed from food to do more intense activities that just digesting food or talking. And of course, continuous exercise raises the metabolic rate you get from activity. So while the 5 basic steps I listed last week are still valid, the amount of energy your body would use to function regularly would go up too. So it’s a win-win all around.

Basic BMR
Now back to our example from last week, we are using a male with the following stats:
Age – 30
Weight – 192 pounds
Height – 6ft (72 inches)

Our basic BMR with no exercise came down to 2000 calories.

2000

General Activity
With only basic low intensity once-in-a-while exercise, metabolic rate increases by BMR x 20% (see the diagram at the top of this post). So his metabolic rate would come down to 2000 + (2000 x 20%) = 2400 calories, meaning his body is burning about 2400 calories a day.

Now consider this: If he amped up his exercise, and starts exercising most days a week, he could increase his metabolic rate by BMR x 40%. This brings his metabolic rate to 2000 + (2000 x 40%) = 2800. That’s a considerable difference! He just burned an additional 800 calories a day by exercising most days! I guess that crazy Michael Phelps diet doesn’t seem so crazy to you now…

Heart Rate
Granted, this is just an approximation, and it varies based on what “most days” and “intensity” mean to you. So the most accurate way to see how much you are actually losing is to calculate it for the types of exercises you do. Yes, there’s a formula for that too.

What the machines at the gym seem not to mention is that the number of calories you burn during exercise heavily depends on your heart rate. The good part is that most machines do have heart rate monitors. What I would advise is to calculate your heart rate during a few different workouts at the gym, and just note the average so you can use it to calculate the amount of calories you burn doing non-machine exercises.

The average resting heart rate is somewhere between 60 and 80bpm. However, if you are very fit or an athlete, your resting heart rate would usually be somewhere between 40 and 60bpm (usually 50 to 60bpm for women). This is just because the more you exercise, the more efficient your body’s circulation becomes.

During exercise, the average heart rate should increase. It would go higher based on the intensity of the exercise. The higher your heart rate, the more calories you should be burning. However, take care not to get above your maximum heart rate.

How do you calculate your maximum heart rate? Here is where I’ll introduce a little caveat. So far, experts have said there is no perfect way to calculate your maximum heart rate. However, the generally accepted estimate is:

Women: Maximum Heart Rate = 226 – Age

Men: Maximum Heart Rate = 220 – Age

This is not particularly scientific, but just what is generally accepted. It assumes that the older you get, the less intense you should be with your heart. Generally, when you exercise, your heart rate can go anywhere from 50% to 100% of this rate above. Fairly intense exercise is usually about 80% of this number. So back to our example, his maximum heart rate would be 220 – 30 = 190.

Maximum Heart Rate = 190

One last point I will make with the heart rate is that when machines spell out a “Fat Burning Zone”, it does not necessarily mean anything. Strive to go as high as you can below your maximum, rather than aiming to be within some phantom fat burning zone.

Actual Calories Burned
So we have the maximum heart rate. Now, we can calculate the number of calories burned during exercise. Here is the formula:

Women: Calories Burned = [(Age x 0.074) + (Weight x 0.05741) + (Heart Rate x 0.4472) – 20.4022] x Time / 4.184

Men: Calories Burned = [(Age x 0.2017) + (Weight x 0.09036) + (Heart Rate x 0.6309) – 55.0969] x Time / 4.184

My question is: Why does it always have to be different for men and women. Well, I guess only God can answer that one…

Back to our example, if our chosen man was doing average intensity cardio for 30 minutes, and had his heart rate at 70% of the maximum, he would have burned the following:

Heart Rate = 70% x 190 = 133bpm
Calories Burned = [(30 x 0.2017) + (192 x 0.09036) + (133 x 0.6309) – 55.0969] x 30 / 4.184 = 374 calories

That sounds like what you see on the treadmill, right? Now you know how they calculated it. We now have a more accurate calculation of how many calories he is burning based on the intensity of his physical activity.

In summary, our 192 pound, 6 foot, 30 year old man with a BMR of about 2000 calories working out moderately for an hour a day would actually be surviving on approximately 2000 + (374 x 2) = 2748 calories per day. You see that this is pretty close to the 2800 number we had calculated before.

We like our diagrams on Eights & Weights, so here’s one for today:

Questions, comments, feedback, concerns? Leave a comment, hit me up at editor@eightsandweights.com, find me on Twitter @eightsnweights, or join us on Facebook by searching for ‘Eights and Weights’.

Cheers Eights & Weights!

Photo credit: Weightloss-Systems.us

Back to Basics Part One: The Math Behind Your Weight Loss Goals

I hear this question a lot (and I’m pretty certain you do too): What do I have to do to lose weight? It seems like such a simple question with a “magic formula” answer. There is no magic formula to losing weight, but there are ways to make the process much less like some sort of black hole. The basics? Diet and Exercise. Besides plastic surgery and weight loss drugs, there is no other healthy way to lose weight. And no, that was not an endorsement for either plastic surgery or weight loss drugs...

Diet
You want to lose weight, but you don’t want to starve, right? And it’s very difficult to start figuring out how much you should eat. However, people have spent years and years gathering information and analyzing data to make the job easier for you. Here’s how it works:

• You consume food
• Food consists of fat, protein, and carbohydrates that provide energy
• This energy is measured in kilocalories (but usually, we just say calories)
• Your body uses this energy to function (run, walk, digest, talk, exercise, etc.)
• Whatever energy is left over that your body did not use is stored as fat

I know that was thoroughly simplistic, but hopefully, it demystifies the process. This is why the calorie is a very important measurement because it helps us decipher what our body is storing as fat. I like to call it the “Eat minus Burn”.

How do you calculate how many calories are in your food? Well, you could hire a Food Scientist, or you could use the cheapest tool available: the internet. As we all like to say, Google is your friend. It’s amazing how many websites available tell you how many calories are in your food; even local food! Some websites even go as far as telling you specific details of the meals in fast food restaurants. We do have so much information available to us.

But then that brings us to the question “How do I know how much I should be eating?” Most people calculate their calories per day for two reasons: One, it’s easier to do daily than weekly. Two, if you do make some mistakes one day, you can leave it behind and move on to the next. However, whatever way you choose to calculate, the calories you should be eating depend on a lot of things because every individual is different. We all have different heights, weights, ages, and sexes. Yes, your sex is a determining factor too!

BMR
To figure out how many calories you need, you need to first determine what your BMR is. BMR is the body’s Basal Metabolic Rate, that is the amount of energy you exert daily just being alive, eating, sleeping, showering, etc. Here is the formula for BMR (W = Women, and M = Men):

W: 655 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age)
M: 66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age)

Yes, men burn more calories just being alive. I know, just one more reason to be upset. Yes, I am jealous in this case. Don't judge me.

Anyway, let’s assume that when you plug in your numbers you get 2000 calories. This means that you can eat 2000 calories a day with no exercise, and maintain your current weight. Our current estimate is:

2000 calories

Activity
Now, if you do some form of exercise (even the minimum), this means you can eat even more and maintain your current weight. Again, you can Google all sorts of exercises, and calculate how much you burn based on distance, speed, etc. but we’ll talk more about the basics of exercise next week. Essentially, based on how active you are, you can estimate how many more calories your body needs by adding the following values to your BMR above:

• Basic walking about: BMR x 20%
• Minimal exercise a couple of times a week: BMR x 30%
• Exercise most days a week: BMR x 40%
• Exercise intensely on a daily basis: BMR x 50%
• Hard labor or intense athletic training: BMR x 60%

So let’s assume that you do minimal exercise a couple of times a week. Your new number would be 2000 + (2000 x 30%) = 2600. You would need approximately 2600 calories just to maintain your current weight. Note that this is an estimate and it completely depends on the kind of exercises you do, but you get the point. Our current estimate is now:

2600 calories

Lose
The next step would be to determine how this number would change if you wanted to lose weight. Now, the body works like this: 3500 calories equals 1 pound. To lose weight, you need to determine how fast you can do it in a healthy way. If 3500 = 1 pound, then you have to have a deficit of 3500 to lose 1 pound. That seems like a lot, right? Let’s go back to our example. If you deducted 500 calories a day from 2600 calories, how much would you get?

2100 calories

500 calories less a day means that you lose 1 pound in 7 days (500 x 7 = 3500). That’s totally doable, right? If you were not in a hurry, you could even spread that out over 2 weeks and make it 250 calories less a day.

But let’s backtrack for a second. Remember that we started on an assumption that your numbers produced 2000 calories? These numbers would change based on what your numbers actually produced. I’ll repeat the formula down here so you can start your own calculation:

Hope this helped! Let me know if you have any questions. All of the calculations above can be also done automatically at this website: Nutrition.About.com. Just in case you don’t really care about the formulae but are still interested in the actual numbers.

Cheers Eights & Weights!

Photo credit: Ehow.com