Can training reduce calories.

Not sure if this is health or training but would like to know if the following is normal or my HR monitor is wrong. Like everyone I have favourate routes that I do because they are nice. One on the NY moors is lovely on an evening. I always wear a HR monitor and burn around 1150 calories (10 miles with hills and a big arse).

I've been away from it for over a month as Ive started training for the BG round so if its not a huge hill no point. It was a nice evening tonight so just went out for a run on my old fave. My garmin tells me that my average HR is just thes same (1 or 2 beats less if anything), the time is over 5 minutes faster (got carried away on relatively flat ground and no rain) but the calories showed 820, over 300 less!!!

I have had a check back at another regular run and that I did last week (it is a big hill so allowed) and that had dropped from just over 1000 calories to just over 700 calories. Again the average HR was the same or slightly less and the time was a little quicker.

So is the HR monitor wrong or is this normal, weight is the same and routes the same, effort pretty much the same so bit confused. The only perceptable change is I am reaching that "ooh this is getting a bit hard" stage about 6 or 7 BPM earlier but then again I have been trying to keep my HR low for a month so no huge shock really.

Any HR clued up people out there?

I'm no HR expert, but it could be that your body's adjusting to the BG training and therefore expecting a lengthy flogging when you don the fell shoes, hence burning its precious calories more carefully. Likewise, longer, slower paced runs make shorter, quicker stuff harder, hence stuff feeling harder sooner.

Certainly in my experience of BG training earlier this year I've been goosed whenever I try a short, sharp run, but find my endurance is still good. That's probably why the L100 seems more appealing than a BOFRA series.

The heart rate monitor has nothing to do with the calculation of calories on a garmin - I get calories burned figures (which I ignore completely) and don't have a heart rate monitor at all. I think the calories figure is calculated based on your age and sex as well as the distance, speed and time etc. That said last time I fiddle faddled with my garmin settings I found out that I was a female!! I didn't realise that I been wrong all these years :D

(theres a chance that your settings may have changed, especially if you've had to reboot the watch??)

Fair point, will have a look at the settings. If its only calculated on age, sex, height, weight distance etc it should have been the same. may be it is the settings have changed, will have a look tonight, thanks stolly.

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Originally Posted by Stolly

The heart rate monitor has nothing to do with the calculation of calories on a garmin - I get calories burned figures (which I ignore completely) and don't have a heart rate monitor at all. I think the calories figure is calculated based on your age and sex as well as the distance, speed and time etc. That said last time I fiddle faddled with my garmin settings I found out that I was a female!! I didn't realise that I been wrong all these years :D

(theres a chance that your settings may have changed, especially if you've had to reboot the watch??)

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Interesting idea and one that I tend to agree with, its just the scale of the reduction 25% is a lot but then again the body is an amazing thing.

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Originally Posted by Hank

I'm no HR expert, but it could be that your body's adjusting to the BG training and therefore expecting a lengthy flogging when you don the fell shoes, hence burning its precious calories more carefully. Likewise, longer, slower paced runs make shorter, quicker stuff harder, hence stuff feeling harder sooner.

Certainly in my experience of BG training earlier this year I've been goosed whenever I try a short, sharp run, but find my endurance is still good. That's probably why the L100 seems more appealing than a BOFRA series.

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Garmins tend to work on Distance and Hr not just Hr alone.
I don't pay much attention to it either.
Fewer calories in than you require = weight loss

Agree with comments above.

I don't use a HR but get Calorie figure from my Garmin. If I do a mile it will give the same amount of calories used whether I have gone up Yewbarrow to start with or jogged along a flat road (I know which mile I think has used more calories!). I think its main factors are sex, age, weight and distance. From my experience the time you take has little to do with the figure it produces.

Anyway, regardless of how they calculate it, its impossible for it to be accurate, although I guess if its consistent you can at least measure one run against another.

The watch sounds like a setting or something has changed though. I get the same figure as you quoted normally i.e. about 110 a mile.

Agree, it has nothing to do with HR, or even speed or sex.

From a purely physics point of view, the amount of energy required to move a certain mass a certain distance is the same irrespective of speed ( I know that doesn't sound right, you intuitively think you must burn more energy if you go faster, but you don't. The effort is more as you are burning that energy over a shorted time period, but actual energy is the same ).

If it is showing a lower figure for the same distance then your weight setting in the watch must have reduced.

That was my thinking of things which is why I asked the question. I light of the replies here I have had a look back through the stats and on one occasion I went out without the HRM and just used the gps and the calorie burn is there. In theGarmin blurb they claim that calories recorded are related to BPM's. It looks like the watch has lost a setting, going to investigate tonight and will report back.

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Originally Posted by Yaks

Agree, it has nothing to do with HR, or even speed or sex.

From a purely physics point of view, the amount of energy required to move a certain mass a certain distance is the same irrespective of speed ( I know that doesn't sound right, you intuitively think you must burn more energy if you go faster, but you don't. The effort is more as you are burning that energy over a shorted time period, but actual energy is the same ).

If it is showing a lower figure for the same distance then your weight setting in the watch must have reduced.

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I read somewhere on the web that taking a blood sample to measure the sugar content is the only accurate way of measuring calories being burnt.

In theory being fitter (or lighter) would mean a lower calorie burn to achieve the same distance and climbs. Not sure it would be that much lower though.

don't use HRM as it tells me i am dead- seems to not like my ribs.
Lost 3kg on B Smitthy- calories burnt. Or was it just dehydration as now weigh the same as usual.

JUst take the view- eat lots. drink what I like- beer and wine, plus whiskey in wn=inter. Run lots and all will be well.
Well it might not be but I will have had a good time

Did some digging last night. The settings are all as they were on the watch. So, the watch hasn't changed 310xt, the run hasn't changed and as far as I can tell I havn't changed. I think I may have found the answer though. According to an article by DC rainmaker the 310 has two ways of calculating calories. The distance+person suggested above when no HR monitor is linked. When you use a HR monitor it does calculate the calories on hearbeat using what sounds like complex maths. The software learns about you and changes as it understands how you work. The BG training coupled to the fact I have done a couple of bike rides without switching it to bike (didn't think it would matter) has no doubt confused it. Going to give it a reset and then while I am on holiday take it on some more normal runs to see if it goes back to sensible numbers.

I have a plain HRM (Polar) you put in age, weight, fitness category, max HR, rest HR.
and it tells you how many calories you have burned.
I always took the absolute values with a pinch of salt but did think the relative values might be useful.

On Sunday I was out for 7.5 hours in the Cairngorms (glorious!) and found myself wondering how many calories the HRM would tell me I had burned (therefore how big a feast was I due)
The I tolfd myself - nah its rubbish anyway
then I decided to have a think about it and came up with this.

burning calories, burns oxygen at specific rates (more oxygen required to burn fat than carbo).
so you can take the number of calories burned as directly related to the amount of oxygen aborbed,
amount of oxygen absorbed is represented by the amount of blood transported,
amount of blood transported is represented by the activity of the heart.

I did a rough calculation in my head.
Assume I normally burn 3000 kcal a day
I'm out for 8 hours = 1/3 of a day
So normally I would have used 1000kcal
but I'm running (and walking) for these 8 hours and my average heart rate is increased I guessed at this being double my daily average (HRM measured at 129 so I reckon that was a pretty good guess)
That means twice the amount of oxygen transported, therefore 2000kcal
But its not only your HR that incresaes, but also stroke volume increases( amount of blood pumped per beat of the heart).
off the top of my head I went for 2.5 times incresa in stroke volume.
giving a total of 5000kcal for the run.

Once I finished I checked the watch - 4912kcal !

so either I'm a genius, it was a lucky guess, or its not all that tricky - I'm going for the last of these.

My HRM doesn't pretend to work out how much fitter you are, it simply asks you what your level is.
Sounds like your watch is being clever and atributing a significant increase in running economy and efficiency -- perhaps too much.

Effect of training is to improve your CV efficiency - i.e. after a period of training a given HR will equate to a quicker pace than you would have achieved at that same HR prior to training, all other things being equal.

From what you're saying, your intensity - HR - is (more or less) the same but you are now working at this intensity for a shorter period of time (because you are covering the route more quickly), ergo you have used less fuel.

If you've updated other settings, e.g. reduced weight if you've lost any over this training period, this will also go to reduce fuel used estimates (as you are effectively running with less resistance).

As to how accurate it is, well it only estimates based on certain parameters it can either measure, or are assumed based on what you tell it (i.e. the settings). It won't factor in other external factors like outside temperature, body temperature, hydration levels, etc. which can all have a bearing on the rate at which you burn fuel.

I said I would post when back in the country and I have a bit of a twist. My holliday dictated that I couldnt run for 2 weeks and the day I got back into the country I got a cold. Now I know that I shouldn't run with a cold but I did and the results were interesting. just short of 15 miles and I would expect something in the region of 1500 calories based on recent outings.

However the lack of training but mainly the cold put my HR through the roof, my average HR was 161 which is normally my max for a run and the max recorded was 184, I have never seen a 180 before without trying to find my max and in fact I don't think I've seen that for over 6 months. Its fair to say I was Ill, not going quick and even had to resort to walking at times. calories recorded 2650!

My conclusion, calorie burn can vary hugely with fitness and you shouldn't run with a cold.

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Originally Posted by beenatitforyears

you shouldn't run with a cold.

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Unless you are trying to loose weight

And enjoy pain, suffering and humiliation.

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Originally Posted by DrPatrickBarry

Unless you are trying to loose weight

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Originally Posted by beenatitforyears

..... and you shouldn't run with a cold.

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Oh yes you should! (said in a pantomimey voice).

I got my first cold in about 18 months last week and, despite streaming buckets of snot and having real difficulties just trying to breath and run at the same time, I persevered. To be fair all I could manage on the first day of the cold (last Wednesday) was a pathetic one and a bit miles but a run is a run... and it has been a terrifically bad cold :). I doubled that on Thursday, even though I felt even worse, and managed over 3 miles on Friday. Normal service was almost resumed on Saturday with a 11.5 miler and, in theory too, on Sunday with 7 odd miles. I actually felt completely washed out, weak and woolly on Sunday though but by then I'd broken the back of the cold and the completely gorgeous weather helped massively. Still bunged up but now back on schedule :D

I don't really know whether you should or shouldn't run with a cold, my usual approach is; if I'm feeling up to a run or want to run, then I run. If I'm feeling really off and just want to rest, I chuck the schedule and don't run. Works for me.

I've found running with a cold to actually help, certainly there has always been an improvement on the cold front post run.

Never ran to exhaustion or anywhere near when cold ridden though, but just enough to get the blood pumping for an hour or two