Garmin 305 Calorie Counting

blu3cat

Hi,

I have a Garmin 305 which I use as a raining aid / cycle computer, and I was wondering how accurate the calorie calculation using the device was.

According to my Garmin, my pretty flat 16 1/2 mile round trip commute eats up about 1500 calories a day - this seems like a lot. Any one else done a comparison with other devices?

always_tyred

blu3cat wrote:

Hi,

I have a Garmin 305 which I use as a raining aid / cycle computer, and I was wondering how accurate the calorie calculation using the device was.

According to my Garmin, my pretty flat 16 1/2 mile round trip commute eats up about 1500 calories a day - this seems like a lot. Any one else done a comparison with other devices?

That does seem high. Its possibly in the region of 1000. Have you put your personal stats into it?

My polr hrm has some calculation supposedly based on your age, weight, and max/resting hr. On a 50-60 minute hilly 13 mile e/w commute it tells me I use about 800 cals.

Its a guide, nothing more. I have compared it to the values on stationary bikes at the gym and they seem similar, but this may very well be because they use the same algorithms.

The only other comparator I have is a concept II rowing machine which, to my knowledge, calculates the energy stored in a flywheel and doesn't pretend to calculate how much the rower expends. The values on it should be a bit higher than cycling because its typically more intense. However they are too similar, for my money, suggesting that my hrm is overestimating.

dodgy

16.5 mile round trip at what speed, up any hills etc? It's not really worth worrying about Calorie calcs on consumer gear, it will always be a rough estimate. Just be assured that ride 'x' will show more calories consumed than ride 'y' if ride 'x' is faster, further (or possibly) hillier.

bratboy

Garmin don't have very good algorithums for calculating calorie usage. I don't think they wanted to pay for the license/usage of more accurate calculators like polar. There have been some updates from Garmin over the years to improve the accuracy so it maybe worth a look on there support website.

Polar are quite accurate and it does depend on your max/rest heart rates, your weight and speed and only records exercise over 90bpm. There are a few site on the web that will calculate for you too.

I would guess your commute take in the region of an hour and thus the 1500 figure seems like it'll be about twice what you really consume.

Hope that helps.

blu3cat

hmmm, seems to confirm what I thought, All the details are entered into the '305 correctly, and there are certainly no big hills (nothing over 2% on the easy route).

Anyone own a power meter and done the conversion to calories from total power used?

John Stevenson

blu3cat wrote:

Hi,

I have a Garmin 305 which I use as a raining aid / cycle computer, and I was wondering how accurate the calorie calculation using the device was.

Not very. I think Jeff has compared the numbers from a 705 and a pukka power meter and concluded that eating to replace Calories measured by a Garmin device would be a good way to end up the size of a barrage balloon.

Garmin says the numbers are useful for comparing one ride with another, which demands the question of why they can't just put in a scaling fudge factor.

blu3cat

Not very. I think Jeff has compared the numbers from a 705 and a pukka power meter and concluded that eating to replace Calories measured by a Garmin device would be a good way to end up the size of a barrage balloon.

Garmin says the numbers are useful for comparing one ride with another, which demands the question of why they can't just put in a scaling fudge factor.

Any idea what the conversion factor is / was?

May also explain my total lack of weight loss no matter how many miles I seem to put in.... :roll:

Stone Glider

Rather than counting calories and taking guidance from "fitness experts" who are thin as a rake and couldn't put on weight if they tried, harken to the "fatties" on this forum for weight loss advice. We have been there, done it and burst the T shirt.

blu3cat

I think the best way to start losing weight again would be to stop eating the contents of the fridge / larder / freezer after every ride.

mmmnom nom nom,
trouble is it tastes too nice
nom nom nom nom.