Cycling calorie counts?

glevinso

gdyment wrote: »

Calories: 1,216 C
Work: 1,597 kJ

I am curious why it is calculating 1597 kj for that ride (which is spot on what I would predict based on the avg and NP), but then says 1216 calories. Perhaps it is calculating it off heart rate instead of power, but your cycle computer should NOT be doing that if it has power available. Your cycle computer should be simply taking that KJ value and calling it calories (KJ expended and calories burned are close enough to the same that they just take one for the other)

glevinso

gdyment wrote: »

Work: 416 kJ

There it is! And closer to my 450 guesstimate.

Mr_Knight

glevinso wrote: »

gdyment wrote: »

Calories: 1,216 C
Work: 1,597 kJ

I am curious why it is calculating 1597 kj for that ride (which is spot on what I would predict based on the avg and NP), but then says 1216 calories. Perhaps it is calculating it off heart rate instead of power, but your cycle computer should NOT be doing that if it has power available. Your cycle computer should be simply taking that KJ value and calling it calories (KJ expended and calories burned are close enough to the same that they just take one for the other)

Just to ditto the curiousity. Especially as converting the kJ number to calories produces a result that actually looks pretty reasonable.

gdyment

glevinso wrote: »

gdyment wrote: »

Calories: 1,216 C
Work: 1,597 kJ

I am curious why it is calculating 1597 kj for that ride (which is spot on what I would predict based on the avg and NP), but then says 1216 calories. Perhaps it is calculating it off heart rate instead of power, but your cycle computer should NOT be doing that if it has power available. Your cycle computer should be simply taking that KJ value and calling it calories (KJ expended and calories burned are close enough to the same that they just take one for the other)

I have been wearing my HR strap (for myfitnesspal more than anything) but as you know with lack of hard sweating it's sporadic. I just assumed the work/cals would have been PM only.

This morning's commute:

Avg HR: 123 bpm (probably)
Max HR: 182 bpm (no)

The saturday 3 hr easy ride one:



My max hr is somewhere around 175 (and I do wet my strap before going). I was not doing any crazy intervals.

SuggaD

I wore my HRM for the first time on a fairly tough ride on Saturday (62 miles, 2500+ ft, 19+ mph winds) and averaged close to 16 mph. HRM said only 1311 calories, which seemed very low for the conditions.

glevinso

Hard to know for certain without a power meter, but I noticed at least Garmin's algorithm seems to be a little low when using the HRM for calorie estimation

Cher1e1n2

I have a mini portable pedal cycle and although I can keep a good pace for at least an hour, my heart rate only goes up to about 110-120. I know its better than nothing and I can do it while watching TV and such so I only count 1 calorie a minute and don't eat them back. Some days I can pedal 3-4 hours.. But I still don't feel like it does more than fidgeting.

Machka9

Machka9 wrote: »

I estimate 400 calories per hour. That seems to be about right given my weight loss.

To be more specific ... I estimate 100 cal for every 5 km.

Generally speaking, I ride somewhere in the neighbourhood of 20 km/h, but if I ride slower or faster, the 100 cal/5 km calculation still works.


Therefore, if I do a 41 km ride, like I did last Sunday ... 41/5 = 8.2 * 100 = 820 cal. I'm not sure how long the ride took me ... at least a couple hours.

KettleTO

I also commute to work by bike April to November. My ride is short enough that time is almost equal to transit and long enough that I get 500 - 600 extra calories to play with a day. I also ride longer distances on the weekend. I generally find MFP really over estimates the calories burned compared to what my HRM tells me. MFP is closest in the spring when I'm out of shape and in the fall when it is colder and windier.

My ride to work is 11 km with a 92 m elevation gain. Home is the exact reverse. Weight has also varied between 190 lbs and 220 lbs. It has taken me anywhere from 28 minutes (home) to 45 min (to work) mostly depending on wind and traffic lights. Wind is the big variable. I've logged between 225 cal (August, tailwind and green lights) and 400 cal (April, headwind and pain :-) ).

Since I've found time dependent on external factors, I like to challenge myself with HR, particularly average HR.

I've also found that for the longer rides (plus 3 hrs), there is a limit to calories I eat back. I never log more than 1500 cal per ride.

gdyment

glevinso wrote: »

Hard to know for certain without a power meter, but I noticed at least Garmin's algorithm seems to be a little low when using the HRM for calorie estimation

More Garmin wackiness - didn't wear the HRM but same bike/route/powertap:

Distance: 17.04 km
Time: 36:26
Avg Speed: 28.1 km/h
Elevation Gain: 103 m
Calories: 569 C
Avg Temperature: 12.1 °C

Avg Power: 158 W
Max Avg Power (20 min): 172 W
Normalized Power (NP): 175 W
Intensity Factor (IF): 0.876
Training Stress Score (TSS): 41.7
Work: 314 kJ

WTH - what other metric could they be looking at?

gdyment

Another:

Calories: 5,246 C

Normalized Power (NP): 167 W
Intensity Factor (IF): 0.834
Training Stress Score (TSS): 361.0
Work: 2,749 kJ

Still would love to know where Garmin is pulling the Calories from. It's not even in the ballpark.

brocantrs

Sounds reasonable to me. I was riding 22 miles and burning around 2000 calories according to heart monitor.

ACyclingAdmin

I've noticed garmin / strava is way off on calories sometimes when it should be a straight kj to cal conversion. I'm typically doing endurance efforts around 210-240 watts which is ~750-800ish kilojoules an hour.

Example here doing some threshold intervals:
https://www.strava.com/activities/312835740
1009 kj's burned, strava reports 1,125 calories. Even with a slight variance in efficiency that's pretty far off as it shouldn't be more than a 3-4% difference in work energy vs calories burned.

glevinso

Weird I have never seen that. I always get exact 1 to 1 on calories to kj