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Eating during a ride and HRM calorie accuracy(11 posts)

Eating during a ride and HRM calorie accuracyPODIUMBOUNDdotCA
Sep 13, 2002 2:47 PM
During a 1 hour roller ride how should I eat? My HRM estimates the consumed calories at as much as 1000 calories. Is this accurate?

Thanks,
Nick
PodiumBound.ca
that sounds a little highDougSloan
Sep 13, 2002 2:59 PM
If you are heavy and really working your butt off, I suppose you could hit that. I've read that 500-700 calories an hour is getting up there, and at least half of that comes from fat stores.

Nonetheless, you shouldn't need to eat anything on a 1 hour ride, and besides, if you are working that hard, nothing is going to digest anyway.

Doug
Its sub-anaerobicPODIUMBOUNDdotCA
Sep 13, 2002 3:42 PM
Thanks Doug. Anyway its a sub-anaerobic effort and I'm a pretty big guy (185 lbs) so I don't know how close it is. I'm just concerned about the effects of not eating as much as I should since I don't want my body to start to fast off the muscle.

Thanks,
Nick
1000 calories/hr = 25 mphKerry
Sep 13, 2002 3:54 PM
A 160 lb rider on the flats with a good position on a road bike will burn 1000 calories per hour at 25 mph. That's smokin' for an honest 60 minute 40K time trial. How can your HRM calculate calorie expenditure, since you and I could have 20 bpm difference in HR and still be putting out the same power. And, as Doug said, there's no need to eat anything for a one hour effort (unless you were totally depleted when you started).
re: Carmichael's post during TdF ???Chainstay
Sep 13, 2002 4:49 PM
In a post on the TdF web site Chris Carmichael said that the racers consume 1000 cal/hr and they tried to eat up to 300 cal/hr. They start the ride with about 1800 cal of glycogen stores. He said that within 1 hour after the ride they tried to eat something like 1500 cals of complex carb and protein to rebuild glycogen. I'm not sure I recall all this accurately and I can no longer find the post. Anyone else know?
You've got it about rightKerry
Sep 13, 2002 5:27 PM
For riders in the TdF, though it will depend very much on the rider (weight) and the day (pace, hills, wind). Eating to replace calorie expenditure is one of the key challenges for a TdF racer. All of this has nothing to do with one hour roller sessions.
You've got it about rightChainstay
Sep 13, 2002 7:12 PM
I know, but it's more interesting. What I don't see is that if they burn up 6000 cals, eat 1800 and consume 1800 in glycogen stores, where does the remaining 2800 come from? I suppose some is still in their blood and gut from breakfast (maybe 1500 cals) and the balance comes from muscle tissue. If so maybe they are consuming 1300 cals of fat and muscle tissue per day. There's no way because that's about 1/2 pound in weight. Have I got this wrong? Do these guys lose 10 pounds through the tour?
You've got it about rightDougSloan
Sep 13, 2002 7:19 PM
The overwhelming majority of energy comes from fat stores, even on those skinny guys. 1 pound of fat is 3500 calories. That's over half of the day's ride for a typical 100 mile or so day.

Glycogen stores, plus initial stomach contents (breakfast), plus about 300 calories per hour of carbs does the rest.

Of read, and studied this very intensly for long distance riding, that one can only process about 300 calories per hour of carbohydrate and about 50 calories of protein while riding.

Note that while riding in a pack, they may be only averaging about 175 watts, which isn't that much, allowing them to burn mostly fat. They train their bodies to do that efficiently. While they blast hard now and then, those episodes are relatively limited in duration.

Doug
Yes. and don't forget you burn more fat the fitter you get and..Old_school_nik
Sep 17, 2002 3:42 AM
these guys are as fit as they come.

-Nik
Here's the mathKerry
Sep 14, 2002 12:34 PM
A trained athlete can deliver up to 300 calories per hour through fat & protein metabolism (mostly fat). The pros actually train to burn fat by both their eating and riding. So, in a 6 hour race, they burn 6000, get 1800 from fat/protein, get 1800 from carbohydrate consumption, have roughly 2000 in stored muscle/liver glycogen, and 500+ in the stomach. They have enough to do the deed, but are close to being fully depleted at the end. The job then is to eat like crazy when they're off the bike and replenish their stored glycogen. Without that stored glycogen, they can't compete the next day. This is why the key to successful stage racing is "recovery" which means more than just rest. It also explains why any digestive problems will put a rider out of a stage race in a day or two.
re: Eating during a ride and HRM calorie accuracyLactate Junkie
Sep 13, 2002 5:08 PM
The best calorie counters around have an absolute accuracy of about plus or minus 30-40%. This is because of the huge variability in humans in terms of efficiency, post exercise caloric consumption, BMR and other issues. 1000/hr may be spot on for you it may be off in either direction by 3 or 4 hundred, no way to tell. The numbers you get from any calorie counter are estimations based on research done on average humans at average exercise levels, whatever that means. It is best to think of the number you get from the hrm in relative terms, for example, if you burn 2000 "calories" today and 4000 tomorrow, you can be comfortable in thinking you have done twice as much work on the second day. Think of the number as work done over a period of time, which is really what calories represent anyway. What you can't do is go out for a ride, burn a thousand calories and figure it is alright to eat three Big Mac's unfortunately that is asking more than you have a right to expect from a heart rate monitor.