Garmin or Strava, who is more accurate?

Missybiker

Hi
I have a super little Garmin gadget (500), does exactly what I currently need. In particular I like it when it tells me the number of calories that I have used (helps with the coffee and cake stops). Then when I upload it, it links to Strava - great I thought, but whenever I look at strava it reduces the number of calories considerably. I did a ride on Saturday - 717 cal burned on garmin, but only 400 on strava (I find it extremely depressing looking at Strava's calories.

Any thoughts as to why this may happen and which is the most truthful one.... TIA

aberdeenal

If you're using an HRM with your Garmin (and also completed all the metrics etc) I would assume that it would be far more accurate than Strava where it'll base calories used approximately on your entered weight?

itboffin

Sorry to be the bearer of bad news but calorie data from garmin or strava needs to be taken with a pinch of salt.

gdcfc1

Also probably your Garmin measures move time then Strava shows you elapsed time so adding in your coffee stop to recalculate speed averages and report how slow you were for the distance.

buckmulligan

This topic has been covered about a bazillion times on here, so have a search.

The short answer is, unless you're using a HR monitor and have accurate resting/max HR values set up on your Edge 500 and/or the Strava website, then you may as well just pick a number out of your ass.

bobones

If you use a heart rate monitor with your Garmin, then it uses the Firstbeat algorithm to estimate energy expenditure. I always found calorie burn estimates on the Garmin were lower than on Strava, and I have been very successful in losing weight using the Garmin figures while counting calories.

teebs_123

Garmin over-estimates by around 30% in my experience. As mentioned, you need either a HRM or Power meter to understand true calories burnt.

For reference, I did a 105 miles/5,500 ft ride at the weekend and burnt off around 3,300 calories over 6 hours, so 550/hour (that's with a PM)

Missybiker

Thanks to all for your responses - I suspect you are all right - I need a hrm. Ive been looking at a fitbit that includes hrm - I cant be bothered with strapping something across my chest before I go out for a ride, so thought something that I just put on my wrist might be worth considering. unsure what a power meter is, will do a search on google and see what it says.

I will check out the site and see other posts on this subject.

Thanks once again for all your responses

johnmcl7

A power meter is probably a lot fancier than is worth considering at this point, they come in a variety of formats (hubs, on cranks, pedals etc.) and basically measure your power output to the bike. I'm being pretty general here but in short, probably a bit too specialised for your use.

I could never get my chest strap HRM to work so I've been looking into one of the optical ones, DCrainmaker liked the Scosche Rhythm+ although it's a little pricey but I'd be interested in seeing the data as I find the calorie calculations based purely on GPS pretty much useless as others have said:

http://www.dcrainmaker.com/2015/11/wint ... tions.html (scroll down a fair bit)

cycleclinic

HRM does not make calorie count accurate. Even a power meter is not spot on. what a PM does is measure the work done on your bike. It does not tell you how many calories are burnt keeping your body warm. On cold day you will use more energy just staying warm in addition to the work you have to do.

Calorie count is only approximate it is a guess with a PM and a bad one at that.

wongataa

Missybiker wrote:

Thanks to all for your responses - I suspect you are all right - I need a hrm. Ive been looking at a fitbit that includes hrm - I cant be bothered with strapping something across my chest before I go out for a ride, so thought something that I just put on my wrist might be worth considering. unsure what a power meter is, will do a search on google and see what it says.

I will check out the site and see other posts on this subject.

Thanks once again for all your responses

Wrist based HRM are not very good on bicycles - see DC Rainmaker reviews.

johnmcl7

wongataa wrote:

Missybiker wrote:

Thanks to all for your responses - I suspect you are all right - I need a hrm. Ive been looking at a fitbit that includes hrm - I cant be bothered with strapping something across my chest before I go out for a ride, so thought something that I just put on my wrist might be worth considering. unsure what a power meter is, will do a search on google and see what it says.

I will check out the site and see other posts on this subject.

Thanks once again for all your responses

Wrist based HRM are not very good on bicycles - see DC Rainmaker reviews.

I'm perhaps misunderstanding you but DCrainmaker recommends a wrist based HRM as it's his favourite, this is what he said about the Scosche Rhythm+:

This is my primary and singular running/cycling/hiking/etc heart rate sensor (when not testing something else). I just love it. While I liked the Mio Link wrist straps, I’ve found the signal too weak in some cases and then also not quite as stable as the Scosche from a measurement standpoint. The Scosche is dual ANT+/Bluetooth Smart, so it can transmit to just about anything. I’ve used it now as my primary strap for almost two years. You’ll see it in almost all my tests these days.

chrisw12

thecycleclinic wrote:

HRM does not make calorie count accurate. Even a power meter is not spot on. what a PM does is measure the work done on your bike. It does not tell you how many calories are burnt keeping your body warm. On cold day you will use more energy just staying warm in addition to the work you have to do.

Calorie count is only approximate it is a guess with a PM and a bad one at that.

Is it though (a bad guess)? There's a lot of triathletes for example that use their power numbers to get a good idea of the amount of calories they need in an ironman.

On that, treebs123, how did you work out the calories you used during your ride, that number seems on the low side?

I was under the impression that you simply take the amount of kj used as read by the powermeter and this would equal the amount of calories used. The conversion of cals to kj cancelling out the 'efficiency' in the system. Can anyone confirm this or use this?

wongataa

Johnmcl7 wrote:

wongataa wrote:

Missybiker wrote:

Thanks to all for your responses - I suspect you are all right - I need a hrm. Ive been looking at a fitbit that includes hrm - I cant be bothered with strapping something across my chest before I go out for a ride, so thought something that I just put on my wrist might be worth considering. unsure what a power meter is, will do a search on google and see what it says.

I will check out the site and see other posts on this subject.

Thanks once again for all your responses

Wrist based HRM are not very good on bicycles - see DC Rainmaker reviews.

I'm perhaps misunderstanding you but DCrainmaker recommends a wrist based HRM as it's his favourite, this is what he said about the Scosche Rhythm+:

This is my primary and singular running/cycling/hiking/etc heart rate sensor (when not testing something else). I just love it. While I liked the Mio Link wrist straps, I’ve found the signal too weak in some cases and then also not quite as stable as the Scosche from a measurement standpoint. The Scosche is dual ANT+/Bluetooth Smart, so it can transmit to just about anything. I’ve used it now as my primary strap for almost two years. You’ll see it in almost all my tests these days.

Some of them he has found to be fine on a bike (if they work with your skin/hairyness of wrist and you are comfortable with the required tightness for them to work). Many others (often in these fitness tracker bands like fitbit) he has found to have woeful accuracy on a bike unless you are doing constant effort on smooth rides (or a turbo/rollers).

If an optical sensor just doesn't work with your wrist or you can't have it tight enough without discomfort then they are useless. If they work with you and they can't track when going over bumps or when doing varied efforts or something like intervals then they are not very good either.

It might take a bit of trial and error to find one that works from the get go.

wongataa

thecycleclinic wrote:

HRM does not make calorie count accurate. Even a power meter is not spot on. what a PM does is measure the work done on your bike. It does not tell you how many calories are burnt keeping your body warm. On cold day you will use more energy just staying warm in addition to the work you have to do.

Calorie count is only approximate it is a guess with a PM and a bad one at that.

Well a powermeter will be reasonably accurate on the actual energy used to move the bike. On the other stuff like factoring in how efficient your body is etc it will be an educated guess but overall the result is more accurate then with no power data as then it is all an educated guess.

deanflyer

Scosche Rhythm isnt a wrist HRM. Its worn on the upper arm. Battery life is max 8 hours versus months/years for a chest strap HRM.

Good product if you don't mind recharging it after every ride.

ForumNewbie

Missybiker wrote:

Thanks to all for your responses - I suspect you are all right - I need a hrm. Ive been looking at a fitbit that includes hrm - I cant be bothered with strapping something across my chest before I go out for a ride, so thought something that I just put on my wrist might be worth considering.

Strapping a HR monitor across your chest before you go for a ride takes seconds so is not really any bother. I've had the same Garmin HR monitor for over 3 years now and it has always worked fine - you just need to wet the pads slightly before you put the HR monitor on. I like to use it when I want to see how much effort I'm putting into my ride, and ensuring I don't try to go too hard on the hills at the start and run out of steam. I never really take notice of what Strava estimates the calories to be. I just know that if I do put a decent amount of effort into my rides, I'll keep my weight down.