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Garmin 305 calories estimate?

FalconarFalconar Posts: 11
edited March 2009 in Training, fitness and health
Out of curiosity, anybody know if there's any accuracy to the Garmin 305 (+HRM) calorie estimate?

Yesterdays training ride was 35 miles in a bit over two hours in the south downs, a little over 2500 foot vertical (to whatever accuracy the 305 can manage) including the Col de South Harting three times via different routes up and a flat 5 mile 'time trial' loop in the middle which was done at an average of just under 23mph. Average heart rate for the ride was 169. For me that's a reasonable workout, but not unduly hard and I still felt good at the end of it. The 305 reckons that burned 1800 calories, which seems very high to me, probably double what i'd guess (although I have no real idea).

So any idea if that's realistic, or just a semi-random number? how does it figure it out? My body weight, age etc. is in the 305 (147lbs, 34 for the record :) )

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  • fuzzynavelfuzzynavel Posts: 718
    Falconar wrote:
    Out of curiosity, anybody know if there's any accuracy to the Garmin 305 (+HRM) calorie estimate?

    Yesterdays training ride was 35 miles in a bit over two hours in the south downs, a little over 2500 foot vertical (to whatever accuracy the 305 can manage) including the Col de South Harting three times via different routes up and a flat 5 mile 'time trial' loop in the middle which was done at an average of just under 23mph. Average heart rate for the ride was 169. For me that's a reasonable workout, but not unduly hard and I still felt good at the end of it. The 305 reckons that burned 1800 calories, which seems very high to me, probably double what i'd guess (although I have no real idea).

    So any idea if that's realistic, or just a semi-random number? how does it figure it out? My body weight, age etc. is in the 305 (147lbs, 34 for the record :) )

    Hi there....this has been discussed before and I think that the general concensus was that the calculations are ok for info only but don't rely on them...they are out by quite a lot.
    I apparently burn 3300 calories on my 50 mile loop according to my 705. Try taking about 30% off it to make it closer to reality.

    I think the reason is that the accurate calculations are all patented by others!
    17 Stone down to 12.5 now raring to get back on the bike!
  • mclarentmclarent Posts: 784
    I did an 80 miler yesterday, and my 305 had me down for >5000 calories...
    "And the Lord said unto Cain, 'where is Abel thy brother?' And he said, 'I know not: I dropped him on the climb up to the motorway bridge'."
    - eccolafilosofiadelpedale
  • sampras38sampras38 Posts: 1,917
    My 705 is well out with it's calculations. As an example it may say I'm burning around 1000 per hour, when the reality is probably closer to 600-700. Not bad as a guide but don't rely on it.
  • GavHGavH Posts: 933
    The simple fact everyone is different with regard to how many calories they burn regardless of whether you're sitting still or hammering up an alpine col. My Polar CS600 used to show about 650/hr whilst doing steady state cycling with an Avg HR of around 75%. My new 705 has that same type of riding as 1000/hr. I disregard that and still assume a figure of 650/hr and more if I've been working a lot harder. Bottom line: its just a guide regardless of where you generate the hourly figure from so what does it really matter? Even the Top Secret patented algorithims can't be 100% accurate.
  • kettrinboykettrinboy Posts: 613
    take off 30-40% of your 305/705 readings and you should be about right, you can fiddle about with the settings in the rider profile to get the readings nearer the truth
  • sampras38sampras38 Posts: 1,917
    kettrinboy wrote:
    take off 30-40% of your 305/705 readings and you should be about right, you can fiddle about with the settings in the rider profile to get the readings nearer the truth

    Agreed. today I did a climbing ride around Box Hill, Surrey, and my Garmin 705 said I burned 6900 calories in 3 hours. It was hard but not that hard..;-)
  • PokerfacePokerface Posts: 7,960
    So - are people saying that the Polar computers give better estimates on calorie burn? They seem accurate to me...
  • akkersakkers Posts: 140
    I use a Polar for running, and its generally spot on, according to HR, speed etc.
    I use a Garmin 705 for cycling. Initially it gave very high results. I contacted them and they told me to download the latest software which I did and now its far more accurate. its still a tad high, but probably only around 10% or so
  • Alex_Simmons/RSTAlex_Simmons/RST Posts: 4,161
    akkers wrote:
    I use a Polar for running, and its generally spot on, according to HR, speed etc.
    I use a Garmin 705 for cycling. Initially it gave very high results. I contacted them and they told me to download the latest software which I did and now its far more accurate. its still a tad high, but probably only around 10% or so
    How do you know?
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
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