The DEBUNKING thread.........myths that need to be trashed

Walking and running are not the same activities and shouldn't be compared. When walking, only one foot leaves the ground at a time. In running, both feet are off the ground. It's more of a jumping action and burns more calories. Now, running slowly vs running quickly probably burns about the same calories per distance, as does strolling vs brisk walking. If I were to hop like I was on an invisible pogo stick for one mile, I'm sure I'd burn a crap-ton more calories over the same distance as running OR walking.

This has been an interesting thread for me, as a physics instructor, to read. LorinaLynn gets it. A quick thought experiment will demonstrate that the physical work done is not simply a function of the distance traveled: imagine running in place for an hour. You didn't go anywhere, so you didn't burn any calories, right? (Not right.)

By the way, for the person who multiplied their weight by the distance they traveled, please understand that you have correctly calculated the work required ... assuming the distance was vertical. Most of us run horizontally.

An exercise for any physics students out there: Jane Doe starts from rest, accelerates to 3.0 m/s in 10 m, runs at that speed for an additional 5000 m, then decelerates to rest over a final 10 m. What is the net work done on Jane Doe?

That's right ... zero.

Thanks james... my question is why is it vertical compared to horizontal?

Thanks james... my question is why is it vertical compared to horizontal?

Portexploit sent me a message, but let me copy my reply here, too.

If you travel straight up a distance Y at a constant velocity, you (or whatever's moving you) do positive work in the amount:

W = mgY

where m is your mass and g is the acceleration due to gravity (9.8 m/s^2 at Earth's surface).

The gravitational force does the same amount of work on you, but it's negative work ( = -mgY). Work is positive if it's done by a force in the same direction as the displacement, or travel; it's negative if done by a force directed opposite the displacement.

The total work done on you is zero (mgY - mgY = 0). This has to be true if you move at a constant velocity; the work-energy theorem says that the total net work done on you is equal to the increase in your kinetic energy. Your total mechanical energy increases, however, because you end up higher than you started. The increase is in the form of gravitational potential energy and is also equal to mgY. If you then fall freely from that height (Y) above ground, you will arrive with a speed V, where mgY = (0.5)·m·V^2. The (0.5)·m·V^2 term is your kinetic energy. The work you did in climbing that height Y is returned to you as kinetic energy.

If you move horizontally through a distance X, and there's no friction (think of an air-hockey puck, where there's ALMOST no friction), no force is required to keep you moving. So the work is equal to F·X, but F is zero, so the work is also zero. If there is a frictional force (F) that opposes your motion, then you have to do work = F·X to travel a horizontal distance X. In any real situation, though, F is going to be much less than your weight (mg).

Sorry to let my inner geek out for a walk like this. I didn't teach all last year, and I think I'm jonesing for it a little.

One other thing, looking back at LorinaLynn's reply (up a couple): she makes an excellent point about traveling a mile by invisible pogo stick and consequently burning a crap-ton of calories. To make that even stronger, consider: suppose she just invisible-pogo-stick-jumps in place for the same amount of time she'd have needed to pogo-stick that mile? You can see that her calorie expenditure would be the same. The net distance traveled -- if any -- is irrelevant.

I really like that quantity, by the way: the "crap-ton." With your permission, I'll borrow it. "My next trip to the dentist is gonna be a whole crap-ton of fun!" :-)

As for the Calorie thing, I have to comment because this has been such a fun conversation so far. Exercise Physiologists don't use Physics equations. First of all, the calories that physicists use do not equal the Calories exercise physiologists use. Ours are Kilocalories and actually 1000 times larger then the physics calories. Second, physicists keep saying we aren't doing any work when we lift a weight and put it back down because the weight is in the same position at the end of the movement as at the beginning of the movement.

What we do use are equations based on VO2 estimations. The reason for that is because the usage of 1 Liter of Oxygen by the body requires 5 Kilocalories of energy. So, if we can determine how many liters of oxygen you use to do something, then we can determine how many kilocalories you are burning doing that activity. There are several ways of estimating these things. Some formulas use heart rate because there appears to be a positive relationship between exercise heart rate and VO2. Unfortunately, if the elevation in heart rate isn't related to the actual activity of the body, then cellular respiration is virtually unchanged so the VO2 doesn't actually increase, meaning you aren't really burning more calories just because the heart rate increases. So, if your heart rate is already elevated by medications, caffeine, smoking, etc. a heart rate monitor isn't going to give you an accurate estimate of calorie burn. Nor is it going to give you an accurate estimate of calorie burn for anything that isn't steady state aerobic activity. (IE: it's inaccurate for intervals, weight training, etc.) The other methods we use to estimate calorie burn include formulas that take into consideration the mass, distance, speed, and incline. These formulas are based on years of research that show them to be fairly accurate for the AVERAGE population. Meaning some people will burn more and some people will burn less based on their fitness level and the efficiency of their body to utilize oxygen, carbohydrate, fat, etc. Those things actually can change within a matter of hours in the same individual too, based on what fuel they have consumed so even estimates based on the same person aren't 100% accurate. The only 100% accurate way to estimate your calorie burn is to live in a human calorimeter. In the calorimeter, everything that is consumed is weighed and measured and everything that is expelled is weighed and measured. You are basically stuck in this room where even the air you breathe is measured for it's oxygen content as you are breathing in and out. So, we do the best we can with estimates.

Anyway, the real point of the calorie thing is not necessarily how many calories you burn in a mile, but how many of the calories you burn are actually being burned from fat as opposed to carbohydrate and protein. Yes, you may burn 500 calories by running for 30 minutes and only 300 for walking an hour, but what percentage of those calories came from your fat stores? If you are doing a lower intensity workout, you can get 50% from fat, or in this hypothetical case, 150 fat calories. At the intensity of a run, however, only about 20% of the calories come from fat, so this hypothetical person would only burn 100 calories from fat. Yes, they burned more calories, but they burned fewer from their fat stores. And isn't it body fat we're actually trying to lose?

Now, if you are trying to improve your VO2 max and strengthen the heart, that has only been proven to be done at higher intensities, so we don't need to cut all high intensity exercise so we get more fat burning. It needs to be a balance, some high intensity, some low intensity, and some moderate intensity so we get all the best benefits to the body.

References:
Exercise Physiology by Powers and Howley
NSCA Essentials of Strength Training and Conditioning
ACSM Guidelines for Exercise Testing and Prescription
And Dr. Green T. Waggener, Professor of KSPE3420 Exercise Physiology at Valdosta State University, Valdosta, GA

As for the Calorie thing, I have to comment because this has been such a fun conversation so far. Exercise Physiologists don't use Physics equations. First of all, the calories that physicists use do not equal the Calories exercise physiologists use. Ours are Kilocalories and actually 1000 times larger then the physics calories. Second, physicists keep saying we aren't doing any work when we lift a weight and put it back down because the weight is in the same position at the end of the movement as at the beginning of the movement.

What we do use are equations based on VO2 estimations. The reason for that is because the usage of 1 Liter of Oxygen by the body requires 5 Kilocalories of energy. So, if we can determine how many liters of oxygen you use to do something, then we can determine how many kilocalories you are burning doing that activity. There are several ways of estimating these things. Some formulas use heart rate because there appears to be a positive relationship between exercise heart rate and VO2. Unfortunately, if the elevation in heart rate isn't related to the actual activity of the body, then cellular respiration is virtually unchanged so the VO2 doesn't actually increase, meaning you aren't really burning more calories just because the heart rate increases. So, if your heart rate is already elevated by medications, caffeine, smoking, etc. a heart rate monitor isn't going to give you an accurate estimate of calorie burn. Nor is it going to give you an accurate estimate of calorie burn for anything that isn't steady state aerobic activity. (IE: it's inaccurate for intervals, weight training, etc.) The other methods we use to estimate calorie burn include formulas that take into consideration the mass, distance, speed, and incline. These formulas are based on years of research that show them to be fairly accurate for the AVERAGE population. Meaning some people will burn more and some people will burn less based on their fitness level and the efficiency of their body to utilize oxygen, carbohydrate, fat, etc. Those things actually can change within a matter of hours in the same individual too, based on what fuel they have consumed so even estimates based on the same person aren't 100% accurate. The only 100% accurate way to estimate your calorie burn is to live in a human calorimeter. In the calorimeter, everything that is consumed is weighed and measured and everything that is expelled is weighed and measured. You are basically stuck in this room where even the air you breathe is measured for it's oxygen content as you are breathing in and out. So, we do the best we can with estimates.

Anyway, the real point of the calorie thing is not necessarily how many calories you burn in a mile, but how many of the calories you burn are actually being burned from fat as opposed to carbohydrate and protein. Yes, you may burn 500 calories by running for 30 minutes and only 300 for walking an hour, but what percentage of those calories came from your fat stores? If you are doing a lower intensity workout, you can get 50% from fat, or in this hypothetical case, 150 fat calories. At the intensity of a run, however, only about 20% of the calories come from fat, so this hypothetical person would only burn 100 calories from fat. Yes, they burned more calories, but they burned fewer from their fat stores. And isn't it body fat we're actually trying to lose?

Now, if you are trying to improve your VO2 max and strengthen the heart, that has only been proven to be done at higher intensities, so we don't need to cut all high intensity exercise so we get more fat burning. It needs to be a balance, some high intensity, some low intensity, and some moderate intensity so we get all the best benefits to the body.

References:
Exercise Physiology by Powers and Howley
NSCA Essentials of Strength Training and Conditioning
ACSM Guidelines for Exercise Testing and Prescription
And Dr. Green T. Waggener, Professor of KSPE3420 Exercise Physiology at Valdosta State University, Valdosta, GA

This doens't make sense to me. You said the more oxygen we consume the more calories we consume. VO2MAX part of the formula for VO2MAX is based on bodyweight. If nothing changes for a person in terms of fitness except weight their VO2MAX would be higher. So according to what you said, or maybe I didn't understand fully you're saying a lighter person would burn more calories, which we all know not to be true.

Another thing you said, about less fat being burned during high intensity. I am pretty sure we all agree on this to be true. As you also know the POC(Post Oxygen Consumption) when we rest from high intensity, we aren't in a anerobic state anymore so most of the calories in theory would come from fat.

One more thing, from my understanding the higher the mitochondria the more fat burning ability. Mitochandria is produced by low intensity work, yes you can do it with high intensity work of course. You pretty much said low intensity work won't increase VO2MAX much. The people who have the highest VO2MAX are endurance athletes, the majority of their training is in a aerobic state.

where do i start

1. "YOU'RE BUILDING AND GAINING MUSCLE, THAT'S WHY THE SCALE IS MOVING"

YES you can build muscle on a caloric deficit(4). (btw 2out of 5 Americans are obese) saying that is rare doesn't mean it can be done. It depends more on your body type. Endo vs Ecto vs Meso each will gain muscle at a different rate and loss fat at a different rate. Meso would build muscle as long as they took in enough protein and stayed over the starvation point, were an ecto couldn't build muscle with out going heavy on calories, an Endo would fall in the category you based your topic on.

2. "YOU ARE BUILDING LONG LEAN MUSCLES"

no you can't change the length of your muscle all you can do is control the size of it . (see below)

3. "I DON'T LIFT BECAUSE I DON'T WANT TO GET BULKY"

Alright ... here we go Look the "Bulk" of your muscle is controlled (in part) by the amount of testosterone(1)you have , most women lack enough to look like a body builder and never have to worry about it. Also (in part) by hypertrophy training(2) which will allow you to grow bigger muscles where endurance training will allow you to get stronger with out the bulk.

4. "YOU CAN'T LOSE WEIGHT UNLESS YOU EXERCISE WITH AN ELEVATED HEART RATE"-

You are right on this one , you can lose weight watching TV and not moving all you have to do is not eat anything.
Does that make it effective? no
does that even make it a good idea? no
If you are going to commit to a weight loss program you have to understand it won't be comfortable if it is you are doing it wrong.
They use to talk about fat burning zone, your HR hits that point you are burning primarily fat, if you amp it up you burn more fat but you will also burn muscle. Its like this you burn more calories doing HIIT every other day opposite steady rate cardio every other day then you will doing steady cardio every day(3). You compare a 2 mile walk to a mile run. a mile run will not only burn more calories but will also increase your Resting Metabolic Rate... meaning you burn more during you exercise and will continue to burn more throughout your day.

Sources:
(1)http://ajpendo.physiology.org/content/283/1/E154.short
(2)http://www.t-nation.com/free_online_article/sports_body_training_performance/endurance_and_hypertrophy_paradox
(3)http://www.teenbodybuilding.com/justin6.htm
(4) http://www.fourhourworkweek.com/blog/2007/04/29/from-geek-to-freak-how-i-gained-34-lbs-of-muscle-in-4-weeks/

Just to point out, you're quoting a source that claims to have put on 34 pounds of muscle in a month. The average muscle gain for a weight lifter is 1 pound of lean muscle a month. I'm not sure I'd put too much stock in that article, especially when he's selling stuff from it. People in a controlled experiment testing a protein supplement put on 8 pounds of muscle in 6 weeks. I find his claims of putting on 34 pounds of muscle with just 4 hours of training in a month to be sketchy, at best.

As for the Calorie thing, I have to comment because this has been such a fun conversation so far. Exercise Physiologists don't use Physics equations. First of all, the calories that physicists use do not equal the Calories exercise physiologists use. Ours are Kilocalories and actually 1000 times larger then the physics calories. Second, physicists keep saying we aren't doing any work when we lift a weight and put it back down because the weight is in the same position at the end of the movement as at the beginning of the movement.

What we do use are equations based on VO2 estimations. The reason for that is because the usage of 1 Liter of Oxygen by the body requires 5 Kilocalories of energy. So, if we can determine how many liters of oxygen you use to do something, then we can determine how many kilocalories you are burning doing that activity. There are several ways of estimating these things. Some formulas use heart rate because there appears to be a positive relationship between exercise heart rate and VO2. Unfortunately, if the elevation in heart rate isn't related to the actual activity of the body, then cellular respiration is virtually unchanged so the VO2 doesn't actually increase, meaning you aren't really burning more calories just because the heart rate increases. So, if your heart rate is already elevated by medications, caffeine, smoking, etc. a heart rate monitor isn't going to give you an accurate estimate of calorie burn. Nor is it going to give you an accurate estimate of calorie burn for anything that isn't steady state aerobic activity. (IE: it's inaccurate for intervals, weight training, etc.) The other methods we use to estimate calorie burn include formulas that take into consideration the mass, distance, speed, and incline. These formulas are based on years of research that show them to be fairly accurate for the AVERAGE population. Meaning some people will burn more and some people will burn less based on their fitness level and the efficiency of their body to utilize oxygen, carbohydrate, fat, etc. Those things actually can change within a matter of hours in the same individual too, based on what fuel they have consumed so even estimates based on the same person aren't 100% accurate. The only 100% accurate way to estimate your calorie burn is to live in a human calorimeter. In the calorimeter, everything that is consumed is weighed and measured and everything that is expelled is weighed and measured. You are basically stuck in this room where even the air you breathe is measured for it's oxygen content as you are breathing in and out. So, we do the best we can with estimates.

Anyway, the real point of the calorie thing is not necessarily how many calories you burn in a mile, but how many of the calories you burn are actually being burned from fat as opposed to carbohydrate and protein. Yes, you may burn 500 calories by running for 30 minutes and only 300 for walking an hour, but what percentage of those calories came from your fat stores? If you are doing a lower intensity workout, you can get 50% from fat, or in this hypothetical case, 150 fat calories. At the intensity of a run, however, only about 20% of the calories come from fat, so this hypothetical person would only burn 100 calories from fat. Yes, they burned more calories, but they burned fewer from their fat stores. And isn't it body fat we're actually trying to lose?

Now, if you are trying to improve your VO2 max and strengthen the heart, that has only been proven to be done at higher intensities, so we don't need to cut all high intensity exercise so we get more fat burning. It needs to be a balance, some high intensity, some low intensity, and some moderate intensity so we get all the best benefits to the body.

References:
Exercise Physiology by Powers and Howley
NSCA Essentials of Strength Training and Conditioning
ACSM Guidelines for Exercise Testing and Prescription
And Dr. Green T. Waggener, Professor of KSPE3420 Exercise Physiology at Valdosta State University, Valdosta, GA

This doens't make sense to me. You said the more oxygen we consume the more calories we consume. VO2MAX part of the formula for VO2MAX is based on bodyweight. If nothing changes for a person in terms of fitness except weight their VO2MAX would be higher. So according to what you said, or maybe I didn't understand fully you're saying a lighter person would burn more calories, which we all know not to be true.

Another thing you said, about less fat being burned during high intensity. I am pretty sure we all agree on this to be true. As you also know the POC(Post Oxygen Consumption) when we rest from high intensity, we aren't in a anerobic state anymore so most of the calories in theory would come from fat.

One more thing, from my understanding the higher the mitochondria the more fat burning ability. Mitochandria is produced by low intensity work, yes you can do it with high intensity work of course. You pretty much said low intensity work won't increase VO2MAX much. The people who have the highest VO2MAX are endurance athletes, the majority of their training is in a aerobic state.

Okay, I think you're confusing VO2 Max with VO2 during exercise. VO2 max is the maximum amount of oxygen that person can consume, which will improve with training. The VO2 during exercise is the volume of oxygen that they use to do that activity. The individual who is advanced in their training will become more efficient and actually consume less oxygen to do the same activity so therefore, their VO2 during exercise will be lower then it previously was doing the same activity so they will burn fewer calories for that activity then they previously did. The formulas for estimating calories burned also take weight into account because VO2 is generally listed in milliliters of oxygen per kilogram of body weight per minute. So, someone who is 50 kg will burn fewer calories then someone who is 100 kg if they are using the same amount of oxygen milliliters per kilogram per minute.

As for the EPOC curve, yes, we have an elevated burn after the workout and yes, it is primarily aerobic metabolism. However, the EPOC doesn't raise the metabolism so much that we even count those calories in our calorie burn estimate, so it's not much from fat stores because it's not a whole lot overall.

As for mitochondrial density, yes that is increased by aerobic endurance training. Mitochondrial density does increase the ability of the body to burn fat by using oxygen. Unfortunately, the research I've seen doesn't indicate that this increase in mitochondrial density elevates the VO2 max for an individual. In fact, it shows that oxygen is produced as a part of the chemical reaction in the mitochondria where fat is being burned, so there will be more oxygen in the body to be exhaled and read as less being used if we are going strictly by the volume of oxygen consumed which is O2 inhaled - O2 exhaled. Therefore, someone with more mitochondria from lots of low intensity training would be able to produce more oxygen in the body for the chemical processes of producing ATP and their VO2 during exercise would be lessened.

Thank you for this thread!!!! This is exactly what I needed to hear today. I just recently starting lifting weights and am currently holding the water weight as a result. My question to you is, should I keep my heart rate lower when doing cardio to allow my muscles to build? I've heard that if you do cardio too intense when trying to build muscle, you can halt your progress?

I dont get why you think you're retaining water as a result of weight lifting.

Because the first physiological response to heavy weight training is actually an increase in glycogen storage in the muscles. Glycogen is stored in 3 times as much water. So, if you store an additional gram of glycogen, you store 3 additional grams of water.

Reference: NSCA Essentials of Strength Training and Conditioning

.

But at the same time aren't you burning glycogen for energy during weight lifting and thereby reducing your glycogen stores?

Yes, you are burning glycogen, but the response of the body to the usage of the stored glycogen is to store more glycogen for the next time you do that activity. It will then store more then it had previously stored to be able to do more work as you progress your training. It generally levels off after a couple of months of steady training to a balanced amount to what you regularly need for your workouts provided you fuel properly with carbs.

Gotcha', thanks.

If the distance it the goal, let's say 1 mile, whether you run it or walk it the calories burned is the SAME.

This definitely doesn't hold true for cycling: 10 miles at 15 mph burns less calories than cycling 10 miles at 18 mph. There is empirical proof of this in a number of places, not to mention my own experience with my heart rate monitor and numerous exercise calculators. Therefore, I don't see how it could hold true for walking or running.

I'm confused too. If I jog a mile I burn almost DOUBLE the amount of calories as I do walking...at least according to my HRM. I'm not an expert, but I don't see how they can be the same.