Additional calories used when carrying a load

mtaratoot

OK, so here's a weird one.

I can go to sailrabbit and play around with getting a different TDEE based on how much I weigh and what my activity level is. That's maybe a very rough answer to my question, but definitely very rough.

Clearly it takes more energy to carry yourself around the more you weigh. Sailrabbit can show that easily. On a daily basis, especially as a more active person, this can be a reasonable amount of calories. It's the same reason why folks should recalculate their calorie goals as they lose weight; as people get smaller, it takes less fuel to schlep themselves around.

I am curious about what happens when a person carries a load. I started thinking about this today because I had walked downtown to pick up mail at m PO Box and mail a few things. On the way home, I stopped at a grocery and loaded up my lumbar pack and one of the collapsible bags I also carry. It is only about a mile or so from the grocery back to my house, and out of curiosity I hopped on the scale when I got home, then put down my groceries and weighed again. It was only about 15 pounds. Not like a big backpack or anything, but it was still 15 pounds of stuff that wasn't part of me. Law enforcement officers deal with perhaps twice this load every day they kit themselves out for work.

I remember a few years ago when I had initially lost weight. I put a Sea-Soft lead SCUBA belt on before I took a walk. I remember feeling it in my knees and thinking that I used to carry more than that around every day. My knees thanked me for losing weight. I loaned that belt to a friend who now uses it when she walks, but not to burn calories, but to increase the load on her bones to help reduce bone loss.

Anyway, does anyone have an idea of how many extra calories it takes a person to carry, say, ten extra pounds a given distance versus just carrying themselves?

This will not affect my logging of exercise; I'm really just curious. I suppose I could estimate how many joules I am expending if I know the mass and distance and then convert to calories. I need to wrap my head back around the units since a Joule has a denominator of "per second per second." I suspect there's also a confounding factor that it would take some energy just to hold the mass even if I wasn't moving, then more energy to move it horizontally as I walk.

Anyone got an idea?

Yeah. I know. It's a weird question. I'm just a curious recovering scientist.

Retroguy2000

You're basically describing rucking, or light to moderate (depending on the weight and time) intensity resistance training. A quick look at estimates for rucking suggest it's quite a lot higher MET than walking. You can try this site I found. I don't vouch for it, I just glanced at it.

https://www.ruckformiles.com/guides/calories-burned-rucking-calculator/

mtaratoot

@Retroguy2000

Thanks for the link. I'll check it out. I am not familiar with the term, although I know what a rucksack is. A first glance suggests the calculation can't possibly be right. I get just under 100 calories just for walking a half hour, and that's already wrong. It adds 150 if I'm on the flat with 20-40 pounds.

penguinmama87

I've never been able to tell an appreciable difference in calories, but it would be cool to be able to work it out. I regularly use a baby carrier with a 8-22ish lb infant, either for puttering around at home or going on walks. It's definitely harder than not wearing a baby, but I also get used to it.

(22 lbs is about my limit; after that baby goes to a stroller or has to suffer with glaring at me through a baby gate if I'm not carrying them around the house, ha.)

Retroguy2000

mtaratoot wrote: »

Thanks for the link. I'll check it out. I am not familiar with the term, although I know what a rucksack is. A first glance suggests the calculation can't possibly be right. I get just under 100 calories just for walking a half hour, and that's already wrong. It adds 150 if I'm on the flat with 20-40 pounds.

Yeah you can add weight on purpose, to make it more challenging. Make sure the backpack fits well. There are specific vests for this, and flat plates you can buy to fit in the vest pockets.

Looking at the site, putting in my own weight, it says 300 cals for walking 1 hour, MFP says 330 for walking moderate pace, and that site said 850 for rucking with 20-40 pounds. I don't know if that's a good estimate, you should look around, and I'd be curious what you find.

If I were near hiking trails I'd definitely be researching this more. Sounds like a great workout.

AnnPT77

I don't know whether this does anything for you, but the Compendium of Physical Activities** has some different METS values for carrying different loads. You can use those with any METS calculator**** to turn the different METS into a calorie estimate.

** Examples in the walking section here, but there may be others in other categories, dunno:

https://sites.google.com/site/compendiumofphysicalactivities/Activity-Categories/walking?authuser=0

**** Like this random one I usually use for stuff I wonder about from the Compendium:

https://ergo.human.cornell.edu/MetsCaloriesCalculator/MetsCaloriesCalculator.htm

mtaratoot

Thanks @AnnPT77

I didn't even think to check the Compendium.

Walking 3.5 mph on its own shows to be 4.3 met. Carrying a 15-pound suitcase is 5.0 met. That's a difference of 0.7 met.

That calculator suggests at my body weight, 4.3 met for 30 minutes is 136.8 calories, and 5.0 met is 159.1 - a difference of about 22 calories. I'd call that de minimis! Oddly, if I just say 0.3 met for 30 minutes, it's just nine calories. Not that even the extra 22 calories means much, but it's a little odd that the calculation spits out a different number for the difference in met versus the difference between the numbers from two different levels of metabolic activity.

This is fun. Thanks for pointing me to both of those.

tomcustombuilder

Unless you’re carrying that load for awhile it won’t make much of a difference so don’t try to figure it out. If you really wanted to get down to it all you have to do is look at the calculator for calories burned at your weight plus whatever weight you’re carrying around and figure that in but that’s just way too much work and probably will be in accurate anyway.

I WILL tell you though that there is an exercise called the Farmers Walk that is probably the best overall exercise there is. It works pretty much everything but your chest.

yirara

mtaratoot wrote: »

Thanks @AnnPT77

I didn't even think to check the Compendium.

Walking 3.5 mph on its own shows to be 4.3 met. Carrying a 15-pound suitcase is 5.0 met. That's a difference of 0.7 met.

That calculator suggests at my body weight, 4.3 met for 30 minutes is 136.8 calories, and 5.0 met is 159.1 - a difference of about 22 calories. I'd call that de minimis! Oddly, if I just say 0.3 met for 30 minutes, it's just nine calories. Not that even the extra 22 calories means much, but it's a little odd that the calculation spits out a different number for the difference in met versus the difference between the numbers from two different levels of metabolic activity.

This is fun. Thanks for pointing me to both of those.

So what's the calorie difference between your normal bodyweight and your bodyweight plus the extra weight, ignoring the mets? Does it also come to about 22 calories more? Because I've been wondering if carrying a backpack with some weight burns 1-2 extra calories compared to being as heavy as 'normal weight' + pack. I'd guess walking changes a bit more with a weight on the back, and possibly burns a tiny bit extra, but I'm not sure.

mtaratoot

yirara wrote: »

mtaratoot wrote: »

Thanks @AnnPT77

I didn't even think to check the Compendium.

Walking 3.5 mph on its own shows to be 4.3 met. Carrying a 15-pound suitcase is 5.0 met. That's a difference of 0.7 met.

That calculator suggests at my body weight, 4.3 met for 30 minutes is 136.8 calories, and 5.0 met is 159.1 - a difference of about 22 calories. I'd call that de minimis! Oddly, if I just say 0.3 met for 30 minutes, it's just nine calories. Not that even the extra 22 calories means much, but it's a little odd that the calculation spits out a different number for the difference in met versus the difference between the numbers from two different levels of metabolic activity.

This is fun. Thanks for pointing me to both of those.

So what's the calorie difference between your normal bodyweight and your bodyweight plus the extra weight, ignoring the mets? Does it also come to about 22 calories more? Because I've been wondering if carrying a backpack with some weight burns 1-2 extra calories compared to being as heavy as 'normal weight' + pack. I'd guess walking changes a bit more with a weight on the back, and possibly burns a tiny bit extra, but I'm not sure.

The calculator that @AnnPT77 shared requires you to input METs. So I'll try a couple. The compendium says "walking, 2.8 to 3.2 mph, level, moderate pace, firm surface" is 3.5 METs, and "walking, 3.5 mph, level, brisk, firm surface, walking for exercise" is 4.3 METs.

Let's say 3.5 METs; Just me walking for an hour would be 223 calories, and me plus 15 pounds would be 247 - an additional 24 calories per hour.

Let's say 4.3 METs, since that might be closer to my normal speed. Walking for an hour just me would be 274 calories, and me plus 15 pounds would be 303, an additional 29 calories per hour.

Neither of these is even remotely significant.

They factor similarly to the other results; I used a half hour since that's how far I walked yesterday. Looking at an hour; Walking at 4.3 METs would burn 274 as mentioned above, but at 5.0 METs (carrying a 15-pound suitcase) would burn 318; a difference of 44 calories. This is clearly more than just adding more weight to my own body, perhaps because it takes different effort to carry things that aren't part of yourself, and probably also because these are all just estimates. It also might actually be at the beginning of some significant difference - it would be a 16% increase in caloric expenditure.

This leads to the last question: If I could oxidize an extra 50 calories by strapping on a 20-pound load when I went for an hour walk, would I even bother? Maybe. I bet I'd walk slower. Maybe I'd rather just walk an extra ten minutes to add the same additional caloric expenditure.

Retroguy2000

mtaratoot wrote: »

Walking at 4.3 METs would burn 274 as mentioned above, but at 5.0 METs (carrying a 15-pound suitcase) would burn 318; a difference of 44 calories. This is clearly more than just adding more weight to my own body, perhaps because it takes different effort to carry things that aren't part of yourself...

If I could oxidize an extra 50 calories by strapping on a 20-pound load when I went for an hour walk, would I even bother?

There's a difference between yourself weighing more, and yourself carrying a load. The former means more calories burned throughout the day. The latter means more effort, higher MET, more calories burned during that exercise time. And if your goal is burning calories, that works. There's a reason they train soldiers with hill hikes and heavy packs, it's hard work.

The other thing is 15 pounds isn't very much, not for my weight anyway. If you want to get serious about it, add more. A quick Google shows recommendations to start at 10% of bodyweight, and progress up to 25%.

AnnPT77

Retroguy2000 wrote: »

mtaratoot wrote: »

Walking at 4.3 METs would burn 274 as mentioned above, but at 5.0 METs (carrying a 15-pound suitcase) would burn 318; a difference of 44 calories. This is clearly more than just adding more weight to my own body, perhaps because it takes different effort to carry things that aren't part of yourself...

If I could oxidize an extra 50 calories by strapping on a 20-pound load when I went for an hour walk, would I even bother?

There's a difference between yourself weighing more, and yourself carrying a load. The former means more calories burned throughout the day. The latter means more effort, higher MET, more calories burned during that exercise time. And if your goal is burning calories, that works. There's a reason they train soldiers with hill hikes and heavy packs, it's hard work.

The other thing is 15 pounds isn't very much, not for my weight anyway. If you want to get serious about it, add more. A quick Google shows recommendations to start at 10% of bodyweight, and progress up to 25%.

I think the main reason they train soldiers with hill hikes and heavy loads is that they're training them for a job that can require long stints of hill hikes with heavy loads, and conditioning is remarkably activity specific.

Calorie burn and conditioning/fitness are two different topics, though I admit that it's common for people on MFP to conflate them. There's some overlap, of course.

I think @mtaratoot's reasoning about calorie burn here is sensible. If someone wants to play out the math for higher carried weights, there may be data in the Compendium for that.

Like him, I'd assume that carrying something that's not distributed like bodyweight is a little less efficient in practice. But I'm not sure how much reliance I'd place on METS vs. a TDEE calculation to quantity that difference. Each is only a general estimate, and each embodies different assumptions and have different potential sources of error.

Fun thought experiment, though.