How Many Calories

ric_stern/RST

Please re-read what i said, you've misunderstood it. I'm perfectly aware of energy expenditure in these sports, they're directly related to the PhD that i'm doing.

Ric

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leona

Even if you do burn more calories running, you can't run for 2-3 rs a day, 6 days a week, like some of us do on a bike, or you'l be overtrained in no time.
make sence?

austex

Bottom line, Ric is correct it has to do with effort expended. Riding on a flat, smooth course with a moderate effort will generally burn less then running the same course with the same moderate effort because you have to support your full body weight when running which burns more calories. But you can increase the intensity to match what you are burning on your runs. And you will probably find that it's less wear and tear on the body (less impact). You can also use a HR monitor to measure the amount of calories you burn (if your HR does this) on a typical run and then adjust your cycling workout to accomodate the same amount of calories. I'm not confident that the hr do a good job calculating calories accurately but it should be an excellent comparison tool.

Also, here's a fairly comprehensive site

http://www.nutristrategy.com/activitylist.htm

Squint

I've been using a SRM powermeter for several years and it allows you do the math with the least amount of assumptions. I weigh about 163 lbs and an easy ride will be about 35 kcal/mi. It's about 1/3 that of running but you ride about 3 times faster.

I've seen some crazy numbers regarding calories burned running. They translate into power outputs beyond what humans can do. A body can only do so much work as measured in watts which is power which is work/time. Suppose on the bike I can sustain 300W, I can't hop off the bike and run at 1200W. It's just not possible. I would be outputting around 300W while running as well and burning around the same number of calories.

That one would have to ride 3X longer time-wise to burn as many calories is incorrect. Unless you are riding at an effort 1/3 that at which you run at. A very, very, very rough estimate would be that you would have to ride 3X longer distance-wise.

I find that one does not burn more calories/time while running but due to the greater efficiency of riding, you just cover more distance in the same amount of time.

Using HR to calculate work is a very rough approximation. With a powermeter, you're already making one assumption and that is your efficiency. A powermeter only measures how much work you do, not how many calories your body used to do that work. A HRM that calculates calorie expenditure probably makes 2-3 more assumptions which renders the numbers basically useless.

jp111

This is not a factual answer to your question, but, I have a Polar A5 HRM, and, on a flat century, one by myself, and one with a group in NYC this summer, the calories totaled 4,800, and 6,500 respectively. On my 21 mile work commute, which is semi-hilly, I burn consistantly 900 calories a day. If you are interested in calorie matters, a HRM that gives you the calorie use, it's worth it !
jp111

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kokopuffs

I appreciate all of your input in this thread.

-T

Wild survivor

I am 33, 170 Kilo's and about 5' 10". Going by my HR monitor, my max is 170 bpm. On a turbo trainer with a HR of about 135 ish I can burn 400 Kcal every half hour. I was just about to write down my last road results but just realised I never switched over to monitor mode. If you want more info, please ask.

Lee

zaskar

calculators on station bikes are way off, yesterday i rode
2 hours 48 min with avg hrt 135 i burned 1631 kcals.
if i ride hard 3 hours 3o min i burn 2400.

Look381i

You didn't read his post carefully. He is saying that calories per unit of time, not per mile, for cycling can be equivalent to jogging, assuming a high rate of power output during the ride.

I have read that a rule of thumb for cycling at 17 mph is 600 calories per hour. Adjust up or down difficulty of terrain, speed, weight of rider and bike, etc.

I have also read elsewhere that cycling burns fewer calories per hour than golf. Having played golf, carrying my own clubs, over hilly courses, and having cycled quite a lot for 30+ years, I can only assume those authors were thinking of cycling at 7 mph or so on a level road.

M2cycler

i came across this website and found it useful. it tells you the equivalent energy expenditure of cycling to running at different cycling speeds.

http://www.active.com/story.cfm?story_id=5941



hmmm. jan ullrich recently rode a ~47km timetrial in a bit less than an hour. acording to the writer he would have burnt more calories walking around a field and hitting a ball intermittently.

is that article on the internet, i would like to read it.

Look381i

--The article you link seems to confirm the roughly 600 cal/hr at 17 mph.

I don't remember where I read the cycling/golf comparison, but I think it was in a magazine health or diet article that included a table of various activities and calories burned. Golf was near the bottom, and cycling was below that. As I said, I am sure the author of the table was not thinking of cycling as we know it.

cincinattikid

Please forgive my naivety, but can someone explain to me why HRM's are so 'useless' for measuring calories burnt during exercise?

I went to a lab and had my VO2max and max heart rates measured. These figures are inputs into my HRM and help calculate an approximation of calories burnt based on the intensity of exercise (reflected as heart rate) and duration. Now why is it that this should be so wrong?? Ive read here that it HAS to be a power X time relationship to get a ball park approximation - well, doesn't the heart rate increase or decrease accordingly depending on the output? And if this is so, isn't it a worthwhile input instead of power (if you dont have a power sensor)?

Even if the approximation is out by say 10%, I could live with that. I would especially appreciate any comments from those PHD's out there


The Kid.

ric_stern/RST

It's not a naive question at all.



Although, as HR increases linearly with VO2, HR can vary under different and the same conditions, depending on many factors (e.g., caffeine use, food, anxiety, temperature, cadence, acute fatigue, chronic fatigue, etc). Thus, at a given workload (power output) HR can vary dramatically (i find that at TT power my HR can vary 15 - 20 b/min).

furthermore, HR lags behind the effort, such that if you do an interval at a given power output HR may not get to where it normally does if the duration is short (or for reasons mentioned above). For e.g. if you ride at TT power for 20 mins, your HR will peak higher than if you do 4 x 5-mins @ TT power. In fact, even if you ride the 5-mins at a higher power than TT power, the long sustained 20-min effort will produce a higher HR. However, riding at TT power for 20mins or TT power as 4 x 5-mins will result in the same energy expenditure.

Mechanical energy expended (kj) = (power/1000) x time (secs)

Estimated energy expenditure (kcal) = MEE (kj).

This is the only way to get a ball park figure. An accurate figure can be calculated in the lab.

It's also important to note that expenditure is dependent upon efficiency (which can only be measured in the lab).



I'm not a PhD yet... the trouble is the approximation will vary wildly depending on what is happening with your HR, cadence, intensity, and the rest of the list i mentioned.

So, if you're trying to track EE for estimating for e.g. energy intake there'll be too many assumptions and errors.

there's some extra info here: http://www.dallastrigeeks.org/Races...08-25-2003.html

Ric

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Blimp

Ric,

love your work.

Some years ago I went on the 'Gutbusters' diet. Briefly, this involved more exercise, and less fat in the diet. I could still drink beer, as long as I 'traded off' beer for more exercise.

Something must have worked, as I lost 17kg.

To you knowledge is their any useful research on the link between beer and cycling - ie., I need to know how far extra I need to ride to burn of a 375ml can of lager.