commuting and calories
 

Have any of you used the many calorie counter websites that let you choose an activity and have you input weight and duration to finally spit out how many calories you burn.

I have been baffled by these websites. It somehow doesn't add up at all for me.
I ride an hour to work (door-to-door), and an hour back. It's about 11 miles, that puts me at 1000 calories for the day burned. Which is an enormous amount. I know, I am actually going faster, an average of 15 mph, and obviously I am not actually riding the whole 60 minutes (prepping before the ride, locking up the bike, stop signs, lights etc). But even if you change it to approx 45 min and 15 mph, the calories burned stays more or less the same.

I should be super-slim and fit if I were to burn an additional 1000 calories each and every day (which I am definitely not). I am actually gaining a little weight, maybe 5 pounds over the last year. Anybody else made a similar experience?

I think it's because they're counting on that time being continuous, "rigorous" exercise with an elevated heart rate. I usually average ~14-15mph on my way in but if I'm on a flat stretch my heart rate may not be elevated at all. It's hills and longer rides where the work comes in.

Personally I figure that I'm burning *maybe* an average of 35 calories per mile while commuting but you really need a heart rate monitor to get a better figure. Those sites are mostly ballpark guesses.

I like commuting and it's partially for exercise but the real calories get burned during 30-50 mile road or 18-20 mile mountain bike rides.

I use Mapmyride on my phone. It takes into account elevation changes, speed, and time stopped. I still think it overestimates, but not by a whole lot.

I use MyFitnessPal.com. It has exercises you can add. It puts 45 minutes of 14-16mph biking at 582 calories.

I use it mainly to keep track of sodium intake. It's crazy how out of hand it can get without keeping on top of it.

Riding for transportation doesn't burn as many calories as riding for exercise.

Still, your weight gain is probably from muscle mass. Remember that muscle weighs more than fat. I used a few online calculators and found I should be eating around 2700 calories a day to maintain my weight. I tracked how many calories I was eating for a few days, and that was about right.

The best approach to eating should be only eating when you're hungry, and eating unprocessed foods (stay away from TV dinners, hamburger helper, etc.).

Thanks for the replies. This is interesting, it seems I am not alone with this question.

Megalowmatt: How did you arrive at 35 cal/mile? It appears to be much more realistic estimate. Did you use a heart rate monitor to calculate that figure?

Accurate calorie consumption measurement can only be done in lab environment.

There are online calculators, sports watches etc. that will give you estimates, but they all have to make a bunch of assumptions and are wildly inaccurate, as you have noticed. If you want a slightly improved educated guess, get a heart rate monitor. A HRM gets a realistic idea of your exercise level (through measured heart rate data and patterns), removing part of the guesswork. Still, they are only less inaccurate.

As stated already, muscle weighs more than fat. That may explain your weight increase, at least when you first start a new exercise regime.

--J

Most likely weight fluctuation would be due to water retention if he recently started exercising.
And muscle is more dense than fat, not heavier.

They're completely worthless.

15 MPH on flat ground is under 100W, where Watts are a rate of work equal to 1 joule per second. It takes 2640 seconds to ride 11 miles at 15 MPH so your output would be under 264,000 joules j in each direction or 528 kilojoules total.

1 calorie = 4.18 joules, although humans are about 25% efficient so you can approximate 1000 calories = 1 Calorie = 1 kilojoule.

Heart rate monitor estimates are useless because they can be off by a factor of two.

A power meter is the only way you're going to get close.

Thanks for this explanation. So if in theory the op averaged 100w for a total of 264,000 joules (in one direction), how is calorie consumption calculated? I'm trying to make sense of your last sentence. If 1 calorie = 1 kilojoule, does that mean the op is burning roughly 528 calories total for the round trip?

1 Calorie is close enough to 1 kilojoule for practical purposes and at 100W he'd burn 528 Calories round trip.

Thanks Drew! So my rough estimate of 35 calories/mile for commuting was off by 1/3.

Compared to my power meter, myfitnesspal is typically off by a factor of nearly 1.5.

one "simple" way to distill it is like this...

this assumes:

1. flat surface
2. standard high-level road bike equipment
3. no head/tail wind

I also naïvely assume that I ride a total of 0m elevation change on a round-trip commute ... so I average my ride to be flat for the day, which makes the chart easier for me to use:

http://bikeforums.net/attachment.php...hmentid=353698

for me, I average 30km/h on my short commute to work (if one believes my cycloputer), which is in between the 15mph and 20mph lines and I weigh roughly 80kg (damn cheap English beer) ... and my RT commute takes 40 mins rolling (20km) ...

so, I end up with about 12kcal/min or about 480 total for the RT commute.

does that seem about right to you guys? 480kcal for 40mins with an 80kg weight at an average of 30km/h (18,75mph)?

from my rough calculations i seem to only burn about 15-20 calories per mile when bike commuting. so for my round trip commute mileage of 29 miles, that's 435-580 calories/day (depending on lake michigan heawinds).

and my ridiculously slow-ass metabolism only requires about 1,200 calories/day without any phyisical activity, so bike commuting allows me to bump that up to ~1,700 calories/day if i want to maintain my weight.

lots of people seem to think that bike commuting is this super-awesome way to get fit, but it you're cursed with a slow-ass tortoise metabolism like me, it's not really that big of a calorie burn.

I've always thought those calorie counters are way off. The scale doesn't lie.

Commuting, or bike-riding in general. People forget that bikes are an efficient way to get around, and that you can easily out-eat whatever calories you just burned on the bike. ;)

beer gets me ... always

i've switched from eating rice and potatoes to eating steaks, which I think prevents carbohydrate loading and weight gain.

the beer still is a killer though.

The scale may not lie, but it isn't as important or more truthful than a mirror.

I've been using a calorie counter app for the past 3 years called Lose It, www.loseit.com -- and it's helped me lose 30 lbs. When you start the program, you enter in all of your relevant stats (age, weight, height, gender, etc.) and pick a goal -- that is a target weight you want to reach and rate (eg, 1 lb/week). I tracked my calories from food and exercise religiously, weighed myself every day, and lost 30 lbs at almost exactly the target rate I chose, which was 1 lb/week. I have successfully maintained that weight for 2-1/2 years now.

As you lose weight, the program automatically adjusts your calorie budget because you need fewer calories as your weight declines. This is sort of frustrating, but if you really reduce your food intake (which you need to do to lose weight), then you gradually get used to eating less. You start reducing portion sizes, cut out unnecessary snacks, and eat healthier food.

Anyway, LoseIt says that I burn about 725 calories per hour cycling at 14-16 mph and 890 calories per hour cycling at 16-19 mph at my age and weight. So, according to LoseIt, I burn between 1500-1700 calories from a typical day's commute that averages about 31 miles over 2 hours. Their numbers are probably on the high side because I generally stay under my budget by about 3500 calories a week, which would mean that I should be losing about 1 lb/week, but I have been maintaining the same weight (with normal fluctuations) for past 2.5 years. However, I followed the same budget when I initially started the program and lost 30 lbs in the process.

I don't know any methods of estimating calories consumed. I recently started using a Garmin Edge 200 bike computer. They go for about $100. It asks me my weight and height. I don't know why height is relevant. It gives me calorie consumption, but I have no idea if it's accurate. I haven't paid attention to calories, at least not yet. I manage to regulate my weight well enough.

See this ride I took on November 19. It says I burned 1,190 calories. I went very slowly because I didn't know the route, and traffic was very hairy. There were also extremely strong winds that day. I weigh 170 lbs (77kg), and my bike is another 30 or 35. I'm 5'9-1/2" (176 cm) tall, if that matters at all.

I just checked my bike computer for yesterday's easy commute.
15.8 mph, so close to the correct speed.
403 kJ per hour measured at the rear hub.
Humans burn about 1.1 calories per kJ work on the bike.
403*1.1 = 443 calories per hour *moving time*
1.5 hours * 443 cal/hr = 665 calories for round trip.

Where does this number come from?

Genuinely curious :)

Idk... internet somewhere. It must be accurate.

http://www.ncbi.nlm.nih.gov/pubmed/18803095 efficiency = 0.257 ± 0.0245
http://www.ncbi.nlm.nih.gov/pmc/arti...394253/?page=4 efficiency = 26.1%
Random term paper I found cited 22% - 26% from:
Prempero, Pietro. “Cycling on Earth, in Space, on the Moon.” European Journal of Applied Physiology, 2000, 82: 345-360

Using 26% from the first 2 sources that closer agree:
1 kJ = 4.2 kcal, so accounting for human metabolic efficiency on the bike, 1 kJ → 1.09 kcal