Sorry if this has been hashed over before, I did a quick search and found plenty on how much CAL to take in whne raing but not much on how much is expended. Just finished my first IM and was wondering how much CAL I was down by the end of the rather long day, I didn’t bonk, felt mostly fine and was just curious.
Run calories are easy to find (around 100-120 cal/mile pending weight), but I look at cycling cals/mile and find them to be too high. Don’t know enough on swim cal/mile.
Any thoughts on this–keep it simple and assume a 70kg person.
Finally, this exercise will mostly amaze folks on how much one can go into the hole without bonking by keeping your effort low enough to stay mostly away from the limited glycogen stores and utilize fat burning.
I was thinking around 5000 CAL (2500 biking, 2750 running and 750 swimming). Any thoughts???
Hey in the 2 IMs I’ve done I burned about 8500 cal for the bike and run combined. My HR monitor doesn’t read very well during the swim but I would estimate that it would be another 700 cal on top of the 8500.
I used the Polar S300 monitor this yr and according to it, I averaged 3550-3675 kcals for the 3-1/2IM I did over the summer in prep for the GFT. At the GFT I had 7634 kcals for the day.
Well given that you’ll get 2.5 times further on a bike than running in a given length of time (so 10 miles running = 25 miles cycling) I’d say your bike cals are MUCH too low in terms of expenditure.
6-800 calories per hour average, more efficient and smaller athletes burn less and larger athletes may burn more (in general). Yes, you can burn quite a bit of stored fat during a long training or racing day if you pace it appropriately. Approximately 50% of calories come from stored fat at 60-75% MHR in the first hour and a higher percentage as the day progresses.
You probably burned more calories on the bike then you are estimating.
run numbers don’t compute. Basic physics says 165 pound runner will burn ~130 k/mi which is 3400 for 26.2. Bike is more dependent on speed because of coasting factor, but you’re on the bike longer than the run, ergo probably more calories. Swim sounds low also.
My guess would be (165 pound guy)
Swim 850 (weg)
Bike 5000 (sweg)
Run 3400 (pretty sure of this one ± 100 calories)
Total ~ 9200
Thanks for all the great input. I didn’t really know where to look and have trouble believing my Polar HR monitor for a given HR on the bike (since it doesn’t know power data), but it would make sense that a given HR would approximate a similar RPE between biking and running so potentially it is still reasonably accurate.