UKC

If I walk a mile carrying half my own bodyweight in a backpack, do I burn 50% more calories than without? Or is it not that straightforward?

In reply to Alyson:

Are you walking on a treadmill?

In reply to Alyson:
I'd expect moving you x2 not to double the calorie count, particularly if the you in the back-pack was quite aerodynamic.

There will be a sorts of overheads that are using calories.
I.e. even if you didn't move at all, you'd still be burning calories.

So say standing still uses 50 calories.

Say moving your mass 1.5mls uses an additional 200 calories.

Thats 250cal.

Moving your mass x 2 = 400cal

That would give a total of 450cal ie not double just moving one of you...

In reply to JLS:

Hmm, ok. Good point. I don't suppose you know whether a sports tracker app when calculating (estimating) the calories I'm burning while walking is also adding on the calories I'm burning just existing?

In reply to cap'nChino:

Absolutely not!

In reply to Alyson:

I'd expect it to have included the "just existing" caliories in it's count.

So my guess is you need to be walking four miles rather than just 1.5 if the post christmas diet plan is to work.

In reply to cap'nChino:

An old paper by David Coley of this parish, drawing from physiology &fitness & health textbooks says that the excess energy consumption beyond resting for walking is about 31kcal/km for a body mass of 64 kg and varies by 1.47% per 1 kg above or below 65 kg.

Which means almost 50% extra walking calories if you carry 50% of your bodyweight.

In reply to Alyson:
Interesting question, so I looked up this calculator

http://www.healthstatus.com/calculate/cbc

For my age height and weight, walking one mile in 20 minutes I get 131 calories. With 150% of my weight I get 197 calories.

I'm sure its not that simple. J

In reply to Alyson:

Basically a joule is if you move one newton one metre, and as calories are related to joules and Newtons are related to kg I would say yes in theory.

In reply to Alyson:


No.

In reply to JLS:


Ha! It's actually the opposite problem (unusually for me) - I'm losing weight quicker than I think is sensible or sustainable. So I'm trying to adjust my eating accordingly and just would like to tighten up my estimate of what I'm burning.

In reply to Malcolm Tucker's Sweary Aunt:

You need to show your workings out or the exam board won't mark you very highly!

In reply to marsbar:

That was my basic thinking too. It can't be far off anyway.

In reply to John Lewis:




This surprises me .

I'm regularly doing 16 miles round a forest complex. (Every weekend atm)

I don't have a Garmin or anything like that to show me figures.
I know I am doing 5 mph the whole way because I know where the 5 mile point is ,and I do it in not much more than 3 hours.

I just assumed I was burning 100 cals per mile. But maybe I'm burning a lot more.

All I know is I'm a hollow shell when I get back to the van.

In reply to Alyson:


Been there.

Walking shifts the Kgs like nothing else.imo.

Mistake I made a few years ago ,when I started my fitness thing was thinking I could still only eat 2000 calories .and not one more.

Got a verbal wake up call that I was far too thin.Strange how people become blind to their build.
Probably eat about 3500 cals now and I must need them.

Some weekends I probably take 5000 cals a day

You've got to put the fuel in the tank .as they say.

In reply to andymac:

Dont think it's actually that easy to assess the calorie burn based on weight / distance / effort. I think there must be a lot of personal specifics in it.

I run and use a GPS with HR monitor which uploads automatically to Garmin & Strava and they procede to give differing figures for almost everything.

As far as I understand (and I may well be wrong) its maintaining a raised HR for prolonged period that is best for reducing weight, short sharp effort builds muscle, long slow burns fat.

Someoone will be along soon enough to correct me I'm sure.

In reply to Alyson:

Can I ask a subsidiary question?

If I just walked 50% further, without the extra weight, would I burn 50% more calories?

In reply to Alyson:

Don't do it! I imagine if I carried half of my body weight for a mile that would probably be the last mile I would ever walk.

In reply to Kirill:

I do do it! My daughter plus the backpack she rides in adds up to just shy of half my bodyweight, and I take her out in it for walks of 2-3 miles. It's hard but not impossible, though it niggles one of my hips a bit.

In reply to Fredt:



Assuming the same terrain/gradient, yes I think you would.

In reply to Alyson:

Hardcore ()

One of my favourite foods is pasta, and apparently you're not ment to eat a lot of that if you're trying to lose weight.

In reply to Timmd:

Well you could put weight on eating grapes if you ate enough of them!

In reply to Alyson:

You would walk faster with lighter weight, hence it would be a little bit more intense (rather than strength exercise), hence the result might be different? Just guessing, but I haven't heard that weight lifters lose more weight than runners.

In reply to mbh:



Surely there is a distinction between extra body mass (I.e. Running body linked to your cardio vascular system) and carrying additional weight.

In reply to PPP:


That's why I asked in terms of a given distance rather than a given time - because it does take me longer, but overall I'm moving a mass M a distance of D which requires a certain energy input.


Well they exercise a certain way to promote fast-twitch muscle gain, but they require a calorific input to do so. Losing weight and burning calories aren't the same thing - it depends how much you're eating. If a 20-stone weight lifter and a 10-stone runner both walk a mile, the first will need/use more calories.

In reply to The New NickB:


That was the doubt which made me start this thread. (That and the fact that it feels a lot more than 50% harder to climb a hill carrying the extra 50% weight..!)

In reply to Alyson:

Simplistic physics doesn't always relate to a 'real world' situation that well, but also your simplistic physics there isn't quite right. Work = force x distance (not mass).

Moving a mass at a constant speed in a straight line requires no work at all. If you imagine putting the load onto a perfectly efficient wheels and pushing it along a perfectly smooth flat road, once you'd got it rolling it would just coast indefinitely with no further effort from you.

When you're walking you're lifting your bodyweight slightly with each pace, moving bits of your body relative to other bits of your body (arms & legs backward and forward etc. - some acceleration/deceleration each time), and overcoming a bit of resistance to your walking (wind resistance, some friction between your feet and the ground, etc..)

Only that first one has a direct relationship to the weight you're carrying, the others are more complicated and I would think likely to be complicated and affected by things like your gait, the surface you're walking on, stuff like that.

And then there are hills - when you're walking uphill you *are* doing some work simply to move the load, which is proportional to it's weight. (And that work, simplistically assuming everything is perfectly efficient is weight (force) x gain in height.)

My google-fu has failed me, but there *must* have been some proper empirical research into this. I bet one of the academic types who post here could dig it up.

I do vaguely remember reading a magazine article that said there'd been some research done into the efficiency of American infantry walking with packs, and they compared them to sherpas (who were much more efficient - no big surprise), but also to a people in Africa somewhere (I forget where), and discovered that the women who walk vast distances with loads balanced on the tops of their heads were even more efficient than the sherpas. (Being a magazine article though, even if I've remembered it right there's every chance it was horribly mis-reporting the science.)

For your purposes though, I wonder if you might be better off using one of those heart rate monitors that estimate the calories burned instead, and measure what the change is with/without your backpack that way. I imagine that would give you a better idea of the proportional increase in how many calories burned (if not the absolute amount) than any rule of thumb being proffered here. (If you'd like to try that and don't have a HRM, I have one you could borrow if you like.)

In reply to deepsoup:

Thanks - both for the detailed response and HRM offer! I do have a one, it's just that it needs the batteries replacing and you're supposed to send it off to Polar to be done... and remains one of those niggling things I haven't got round to. Yadda yadda yadda. Pull your thumb out Alyson and get on with it.

In reply to Alyson:
Thinking about it, you perhaps need to factor in the temperate outside in which you're exercising too, as we apparently burn more calories while exercising in the cold.

In reply to The New NickB:

Hmmm. I hadn't thought that through. You and Alyson may have a point!

On the other hand - we'd have to look a those sport, physiology & exercise books David was citing - if I put on 50% of my bodyweight as flab, and my CV system didn't change, how would that be different to carrying the 50% in a rucksack? I can imagine it might even be harder, what with all those bits flailing around, rubbing against each other and getting in each others way. A neat set of weights on your back seems much more ordered.

But if the question is whether a 50 kg person carrying 25 kg on their back would burn the same per unit distance as a similarly shaped but bigger 75 kg person. The smaller person would have a smaller engine, that would need to run at higher revs. it would feel harder for her, The bigger engined behemoth could run at lower revs, and so it would feel easier, but would be pushing more (fluids, muscle contractions etc) around per rev (heartbeat) and so the calories burned per rev would be greater, and in the end, therefore, the calories burned per distance covered would be about the same in each case.

So, I suggest that yes you would burn about 50% more calories if you carried 50% of your bodyweight than if you didn't.

In reply to mbh:

I think carrying 10kg on your gut may well be harder than carrying it on your back, so in that sense, I suspect I disagree with Alyson. You are not providing life support to the rucksack.

Of course if you put the weight around your ankles, it is going to be a lot harder.

In reply to Alyson:
Keep in mind that the metabolism continues to work more quickly on the day(s) following exercise, to possibly complicate your formulae further. ()

You may burn more calories if you did it while the metabolism was working more quickly following previous exercise than after enough time had passed for it to return to a slower pace.

In reply to The New NickB:


No but I'm talking to its contents the whole time, pointing out horses and sheep or singing The Grand Old Duke Of York, and occasionally I hear "dishoo" and I have to dislocate my shoulder trying to reach round and wipe a little nose with a tissue.

In reply to Alyson:

Kids are tiring even when not carrying them, but I think you may be testing the limits of science here.

In reply to The New NickB:

So in terms of child care, about 18 months from now?

In reply to Alyson:

>... and occasionally I hear "dishoo" and I have to dislocate my shoulder trying to reach round and wipe a little nose with a tissue.

Awwwww. Cute!
<barf>

In reply to Alyson:


A small hand held mirror could help in directing the tissue nose-wards?

In reply to deepsoup:

It is cute.

In reply to Alyson:


That's what hair is for, surely?

In reply to Alyson:



If I may complicate things further, it is worth remembering that you don't metabolise all of the calories you eat. This changes due to factors such as how well you chew your food, how much energy your body needs for a particular circumstance and what sort of food and how much are you eating...

So in answer to your question about straightforwardness - I think it is not so simple and you would definitely need to know the calorific value of your turds and farts too.

Regarding the niggle you mentioned with your hip carrying your nipper - you should be careful with that. We have tried a few carriers and I like the Tula one we have for comfort and lightweightness, although my 15 month old just wants to walk everywhere now

In reply to Alyson:

Basal metabolic rate covers the staying alive bit. For me, a 70kg male it's 1900cals. That's only 80cals an hour. Compare that with 120cals a mile. Say 3.4mph, the actual basal bit is only 80/480 (16% of the cals).

The basal figure is fixed as per your size. So the heavy person will do more work. But only a small proportion more. There are basal metabolic rate calculators if you want to play with real world figures.

In reply to Baron Weasel:


Mine too but it does involve stopping for every puddle, bright leaf, piece of litter, bird, worm, person and interestingly shaped twig. Sometimes I like to put her in the backpack and travel further than 200 yards in an hour

In reply to Alyson:
Perhaps you could carry your nipper on your shoulders, and work some triceps exercise into your walks by swapping between carrying and them walking. ()

In reply to DancingOnRock:

A few years ago now I wore a HRM for 24 hours to see what it calculated my basal metabolic rate as. It came out at 1800 which is the figure I have sinced used as a starting point whenever I want to lose a pound or two. I found it useful to know that if I ate the recommended 2000 kcal a day for a woman I'd put weight on.

In reply to Timmd:

Sounds like a good plan

In reply to Alyson:

Do that for a year and according to some theories, you'd put 10lbs on.

In reply to Timmd:


I've wondered about this from time to time. It seems logical that colder weather means more energy burnt keeping warm - but as I understand it the majority of energy used while exerting is 'wasted' as heat. Wouldn't the body just make less effort to dump this (sweating and so on) as temperatures drop, so the energy used would be about the same until the point where the temperature got so cold more heat was being lost in keeping warm than was being generated as excess?

In reply to nufkin:

You're dumping loads of heat in the moisture your breath.

Then when you inhale you're pulling in huge amounts of cold air that has to be heated to body temperature.

The excess heat you generate in your muscles is lost regardless of whether it's hot or cold as it's just a by product.

The hotter it is, the harder it is to lose the heat, but you still have to lose it.

In reply to DancingOnRock:


That makes sense - presumably breathing through the nose where possible helps reduce this. Or one of those heat-exchanger masks if you're feeling showy.

But there isn't a specific mechanism for heating the lungs, is there? It would just come from the heat in the blood, would it not, which in turn would come from the heat generated by the muscles doing stuff? So no extra heat needing to be generated, and no extra calories burned

In reply to nufkin:

Not really. The heat is in your legs (or arms), not your abdomen.

You're heating the air through your nose, windpipe and actually inside your lungs.

http://www.backpackinglight.com/cgi-bin/backpackinglight/00184.html#.VL-cGt...

In reply to Alyson:

I gave my nephew the hiccups by tipping him upside down over my shoulder.

A strange mixture of guilt/responsibility and amusement were swirling around while he hiccuped!

'This is kind of funny...but it is my fault...but it is funny...' He didn't hiccup for long. (:~))

In reply to Timmd:
In case that sounds mean, I'm a kind uncle (I've been told) , but there was nothing I could do about the hiccups once they'd started, and not seeing the funny side wouldn't have stopped them...

In reply to Timmd:

Don't worry. I'm a dad and I've done far worse.