Thoughts on calorie burns

My ramblings about your ramblings:

With regards to how hard something feels, don't we have to take conditioning and neuromuscular adaptation into account?

For me, running a mile in 10 minutes isn't much harder than walking a mile in 20 minutes, but I remember when it was. I wasn't conditioned for it. Back in that day, if I based my calorie burn on how hard I FELT my body was working, I would have thought I was burning a lot more calories than I actually was.

Doing 15 squats with a 65lb barbell would be nearly impossible for me right now. It would get my heart rate up, and my muscles would need a break at the end of it. 2 years ago pre-injury, that was my warmup before my working sets. I banged it out and didn't even think about it.

I imagine in either of these situations, the difference in calories burned due to heart rate would be very few compared to the calories burned by the exercise itself.

And then you're also comparing a constant exercise (walking 20 minutes) to an interval exercise where there are longish periods of rest. You may have spikes in calorie burning during a weight training session, but a good portion of your session is spent recovering, i.e. doing no "work."

Aaron_K123 wrote: »

sijomial wrote: »

I've never understood the "don't log weight training calorie burns" argument.
Let's use the MFP rough estimate (based on METS) of about 250 cals for an hour for me.
Most people calorie counting would advocate logging a buffet meal where it's impossible to be accurate but your best guess is 250 cals. So why not log your best guess on the other side of the equation?
I just accept there's no practical way to estimate the burn (HR is meaningless for strength training as is perceived effort) and have a wild stab at it. Could well be low for me as I tend to move more weight in my hour than I guess is the "average".

Also clearly there isn't a difference in calorie burn between a stationary bike and an actual bike so your movement over distance doesn't matter as much as the movement of your legs themselves so not sure if the whole "work" thing works, so to speak.

It's the power you produce not the twirling of your legs that is the real measure of work.
My smaller, but much more talented, cycling mate can produce 30% more power than me for the same cadence.
That energy may be expressed as heat from a friction based resistance brake, or moving a huge volume of air with fan resistance, or (outdoors) moving your body mass from here to there.

Oh yeah I don't disagree with this. I'm just wondering about the difference between something that does not have much percieved effort (walking) versus something that has a ton of percieved effort (weight training) and if the reason for the discrepency is one has more "work" in terms of transport of mass over distance than the other. I'm just commenting on how the common sense of "well this is harder so it must burn more calories) clearly fails us.

I guess my question is this to make it more simple. Is the fundamental part of caloric burn weight transfer over distance or is it something else?

I think part of the problem is people's definition of weight training vs cardio. A lot of the people, and this is complete observation over the years, discuss cardio as LISS (running mainly) for fairly long periods of time. But when the discuss weight training, it mainly refers to going to a gym and doing a bunch of random things. Even if it's a program like stronglift, the length of the program isn't equal to that of their cardio.

Aaron_K123 wrote: »

Now obviously there is another variable which is time. If I walk 1 mile in 20 minutes or run 1 mile in 10 minutes I have moved the same mass over the same distance but presumably I burn more running because I do it in less time which increases the intensity.

Walking, you always have one foot on the ground. Running, you jump from one foot to the other. So you're actually doing a lot more work when you run vs walk the same distance.

Aaron_K123 wrote: »

So intensity (kind of determined by heart rate) plays a role, just not sure how much.

The standard formulas suggest that walking a mile in 20 vs 30 minutes should burn the same number of calories. Riding a mile on a bike is different because you can coast (not using energy) or you can pedal (burning calories). Also the faster you go, the more work you have to do overcoming air resistance, but it's not a meaningful difference at walking speeds.

Aaron_K123 wrote: »

Also clearly there isn't a difference in calorie burn between a stationary bike and an actual bike so your movement over distance doesn't matter as much as the movement of your legs themselves so not sure if the whole "work" thing works, so to speak.

Very strongly disagree. On a stationary bike only your legs are moving, your body remains stationary. You have to push hard enough to overcome whatever resistance the machine is set to. On an outdoor bike, you're moving your entire body weight against gravity and against the wind. How hard you push is dictated by conditions. What I'm saying is riding an outdoor bike up a hill will burn more calories than spinning lightly.

Aaron_K123 wrote: »

The_Enginerd wrote: »

The weight * distance engineering definition of work analogy breaks down in your example though because you are lifting that weight against gravity. You are effectively doing work every time you lift something. When walking, you are moving (mostly) horizontally. You don't need anywhere near 170 lbs of force to move since you are overcoming just frictional losses.

I logged my calorie burns for weight training, because I was losing slowly without it, and with the variety in my activity level from week to week, I prefer that method over building it in.

Yeah that is a good point. I guess the real equivalent would be climbing a mile-tall ladder which is obviously insane. So yeah obviously the incline of the distance has a big factor of how much weight you are really moving against gravity.

But assumption errors and calculation errors aside is the core of how much calories are required come down to the transport of mass over distance (where the amount of mass is the amount you are moving against gravity)? In otherwords exercise X moves more mass over distance than exercise Y then exercise X burns more calories no matter how "hard" exercise Y is.

I think the biomechanical efficiency would throw off such a simple comparison.

Even going on a perfectly flat path where you don't need to account for moving weight against gravity, walking burns a bit less than 1/2 the number of calories/mile as running because there is a lot less "wasted" motion and force that doesn't go directly into propelling you forward. Most of your calories burned during running are burned propelling yourself upward a little with every step, absorbing the impact of each step, and generating force to move lift/bend your legs and move them against their own inertia.

I struggled with the same mental block that @Aaron_K123 pointed out. For a while I couldn't accept that the calorie burn from walking was as high as it is. I'd think about what it takes to burn 250 kCal on a bike and by walking; cycling as a workout, walking as leisure and for relaxation. I'd point to my elevated heart rate on the bike and be incredulous. Of course walking burnt calories, but surely not that many. (On the other hand, I spend 99 % of my time on the bike sitting down...)

Walking on level ground is not a high-intensity activity, nor is it a particularly big calorie-burner.

The aerobic intensity of walking on level ground is between 2 and about 4.5 METs. For an 80kg person, that's 160-360 calories per hour. (Activities such as incline walking or hiking with a load are not "walking"--they are completely different activities). Walking can be a successful walk of weight loss because it can be done for longer periods of time and it can be done frequently. So it means that someone, esp a beginner, can accumulate a useful volume of work if they can put in the time.

A similar concept can apply to lifting weights. While the direct burn during the activity itself may be modest (although it can be the equivalent of walking on the level), it can also be done for extended periods. That plus the "afterburn" likely means that one can reach the 300-500 calories per workout session recommended for a weight loss program. I suspect that most of the people who say "I only lift weights, never cardio, and lose weight" are lifting for at least 60 min per workout (it only makes sense if you are someone who really enjoys lifting and doesn't like cardio).

So, I think sometimes weight lifting gets undervalued as a calorie-burning tool. Again, just because it doesn't burn at the highest rate (cals/min), doesn't mean it can't burn at a sufficient rate to augment weight loss efforts.

The reasons for the discrepancies in calorie burn vs perceived effort for weight lifting vs cardio are pretty straightforward. Calorie burn is increased by a metabolic demand that increases cardiac output, i.e. a volume load. Elevated heart rate during aerobic exercise is accompanied by an increase in oxygen uptake.

Heavy weight lifting places a pressure load on the heart, mostly due to increased peripheral resistance and increased afterload. This results in a dramatically increased heart rate, but LITTLE increase in cardiac output and oxygen uptake. So you feel like you are working harder, and heart rate increases, but oxygen uptake does not increase the same way it does when your heart rate goes up during cardio.

(This effect occurs to a much lesser degree in different types of cardio as well--at the same aerobic effort/calorie burn, exercisers report notably higher rates of perceived exertion on steppers and bikes compared to running on a treadmill. Why? Increased resistance for the legs).

The intermittent nature of heavy weight lifting also plays a role. Intensity during a heavy squat is higher, but the longer recovery period means the overall cal/min of the workout session is lower.

The "lifting weights burns fewer calories" statement is also complicated by the fact that there are an infinite variety of "weight training" workouts. Routines like boot camps or other higher intensity circuits will burn more calories than 4 RM squats (however that will also lessen the quality of the strength workout).

The "log or don't log" question is personal and subjective. When I did log exercise, I wouldn't log strength training because a) I burned 500-900 during my cardio workouts, so the extra lifting calories didn't seem that important; b) I only lifted for 30-45 min, so the total burn was not that great and c) there are so many variables, it would have been a made up number anyhow. I just looked at it as "buffer" to help with the inherent inacccuracies of logging.

I concur with others who promote the TDEE method. Most recently I used my activity tracker (Polar V800) to track my TDEE. I found that if I kept that number over 3200 cals/day, and kept my intake to 1700-2000 cals/day, I lost weight. If I ate more or was active less, I plateaued. It was very simple.

So I think I am a little late to the party, but wanted to chime in on this. It is impossible to accurately calculate caloric expenditure from resistance training, as we still don't understand post-exercise energy expenditure. It is estimated that for every calorie you burn with heavy resistance training it takes 4-5 calories to recover/build muscle. So an hour of high intensity weights can easily burn 1000 calories. You can also burn practically no calories in an hour at the gym doing low intensity work, or just messing around (which is 99% of the people I see in the gym).

Simply put, we do not understand how to quantify energy expenditure for weight training, and the component that is expended during training itself is potentially a small fraction of post-exercise expenditure, something we only also see in Tabata and similarly intense HIIT protocols.