Since I have replaced my stolen bicycle, I have been trying to ride the new one as much as possible- riding to the convenience store, going to pick up take-out, going to a friend’s house. Armed with sunblock during the day, and a light at night, I can make several short trips throughout the day.
I want to get a more accurate idea of the calorie burn while doing so. According to the calorie burn calculator at shape.com, a woman my size will burn approximately 84 calories for 15 minutes of riding at 6 mph. I guess I’m riding about 6 mph, the only other option was 12 mph, and I’m sure I’d have to kill myself to reach those speeds.
Things that increase the calorie burn:
[ul]
[li]The weight of the bike- it’s an old cruiser, I’d bet it weighs 20 or 25 pounds. Or at least, significatly more than newer, lighter bikes.[/li][li]The lack of gears- any incline, even the slightest, requires a lot more energy to maintain my speed.[/li][li]The weight of any cargo- take-out, a 12-pack, my school books. It’s only a few pounds, but it’s gotta do something, right?[/li][/ul]
Things that reduce the calorie burn:
[ul]
[li]Intermittent pedaling- I’ll coast while going downhill. I don’t want to gain too much speed (and believe me, the weight of the bike makes it a rocket when heading down towards the water), I have to stop often and only have coaster brakes (the ones where you push the pedals back).[/li][li]Stopping often- waiting for lights, stopping at stop signs, etc.[/li][li]Hi Opal ?[/li][/ul]
Do these things cancel each other out? Does having to stop frequently at lights lower my heart rate a lot? Or does having to gain momentum again (no mean feat on an old heavy bike) make up for it? What about the shortness of the trips- 15-20 minutes (one way) is about the longest ride I’ll take. It’s hot as balls, I don’t want to be sweating my ass off. How would the calorie burn of several short trips, totalling 60 minutes per day of cycling on city streets, compare to an extended trip on a recreational trail?
Right, 6 MPH is just a bit faster then a fast walk. Intermittent biking on streets, with stops for traffic lights, coasting, etc, makes it difficult to come up with a general number. The weight of the bike and cargo probably doesn’t make too much difference; your own weight is greater then both combined by quite a bit. Gears don’t really change the amount of work you need to do, but they make you more efficient. You will put out the same effort, just over a different period of time, at least to a loose approximation.
If you are interested in increasing the number of calories you spend, you can work harder than you need to when you have a long straight stretch, and then let yourself calm down at your natural stopping/coasting points. There are people who think that varying your elevated heartrate during a workout is a good idea and it makes sense to me.
I have had a great deal of success with such a moderate “interval”-type regimen on my bike (I ride to work during the summer months).
12 mph is more realistic you think? Hmmm… I know that I live almost exactly (to within a couple hundreths) one mile from the grocery store, but riding there involves all the stopping and waiting, so it’d be difficult to actually gage my speed. Now I think about it, the leisurely ride down to the waterfront with a couple of friends this weekend seemed incredibly slow- I had to brake often so as not to run into the bike in front of me. And we were definitely riding faster than a brisk walk.
I want to start riding strictly for exercise as well, but short of circling the lake nearby endlessly or riding 5 or 6 miles up to the recreational trail I’d still have to deal with street lights and stops signs.
I guess I just wonder how to figure out how city biking compares to these estimates for calories burned. During a 15 or 30 minute ride around here, I’d bet half of my time on the bike would be coasting or waiting at stop lights. That kinda sucks in terms of exercise efficiency. It definitely gets the heart pumping… and the sweating, but the heat has a lot to do with that. Better than nothing, but I want to lose weight. I mean, I lost 10 pounds the first year I lived downtown because I started walking so much more, but it’s balanced out now that it’s a normal occurance.
I know you didn’t ask ;), but accurate calorie counts for biking are a fool’s errand. With gears, hills, irregular speed, weight of bike, and the other things you mentioned, there are too many variables.
If you are working, you will know it, because you will sweat and become short of breath. If you are not, you basically might as well be walking. Which is fine too, but you would burn more calories walking to the store simply because it would take you longer. A bike is a very efficient mode of transportation at low speeds.
I’d estimate that my 40 minute high-speed ride in the morning burns about what I’d burn in a high-intensity ten-minute run. But the number of calories I burn during the ride is unimportant- I’m looking to vary my heart rate and get my metabolism going. I have a long term goal of losing some weight and lowering my resting heart rate.
I have a pretty accurate speedometer on my bike, and 6mph is SLOW. The only time I’m doing less than 6mph is struggling up a very steep dirt track in bottom gear, or getting held up behind pedestrians on mixed-use paths.
On the flat, and pedalling gently in an appropriate gear (i.e. not feeling as though I’m pressing the pedals hard) I’m normally doing 12-14mph. On the flat and pushing on a bit it’s about 16mph-18mph. Maintaining 20mph on the flat, at least on a mountain bike with fat tyres, is pretty strenuous.
As for calorie burn, I’d say all the stopping at red lights etc would increase it quite a lot. Think of all that energy that the brakes are scrubbing off each time you stop. You have to build up your speed again, and it’s the acceleration that needs the work. Once you’re going at a constant speed on flat ground, the only work you’re doing is that needed to overcome friction (air resistance, rolling resistance of the tyres, etc), which admittedly can be significant!
To be honest, an approximation is all you’re ever going to get. 80-100 calories per mile seems reasonable, but there’s so many variables (you’ve outlined a couple) that any “guess” is simply that. You forgot to factor in whether you’re going with the wind or against it, and how fast the wind is blowing. How about clothes? The weight and wind drag of heavy clothes can help you burn more calories than skin-tight biking clothes.
A lot of little variables add up to 1 big one, so an estimate will have to be good enough. If you’re out for exercise, calorie burning, and weight loss, focus less on short rides and more on long ones, keeping that heart rate up for as long as you possibly can.
I agree with Colophon, you are most likely burning more energy with all the stopping and starting. Like a car, this isn’t great for conserving energy, and most likely you are burning more calories than you think. Also, 6 mph is ridiculously slow. I bike on a mountain bike which aren’t exactly known for speed. I can maintain 15 mph without even thinking about it, but as was already posted, doing 20 mph take a ton of effort.
This is true if you are measuring things by distance. If your ride is 1 mile and you have to stop and start 15 times you’ll burn more calories then if you ride it without stopping.
But, if you are measuring things by time then it’s probably not true. If you go for a 30 minute ride and have to stop and start 15 times you’ll probably burn fewer calories then if you ride constantly for 30 minutes.
No matter what, getting out on the bike is a good thing.
I don’t agree with that – at least assuming the stops are short and you’re not spending a large slice of the 30 minutes sitting stationary. As I said before, cycling at a constant speed on flat ground only requires enough work to overcome friction and air resistance, which at slow speeds is not that great, although it increases rapidly at higher speeds. On the flat and with no headwind, you can trundle along at 12mph quite happily with very little effort, but if you have to keep slowing down to a halt and then accelerating back up to 12mph, you’ll be doing much more work (again, assuming you’re not sitting at a stop light for a whole minute or more on each of those 15 occasions).
I wasn’t thinking about trundling along at 12 MPH; I generally ride 16-18 MPH and it’s pretty hard riding. Stopping and starting is a break in the exercise, not additional exercise to accelerate. Even so, coming to a light or stop sign you generally coast for quite a ways, then pause at the light for anywhere from 10 seconds to a minute. I think in a timed ride that would be a net minus.
I don’t think I could get up to 16 or 18 mph on my bike, since it’s all old and slow. Even on the recreational trail, when I didn’t have to worry about stop lights as much and had nice flat straightaways, the guys in spandex blew past me regularly. That’s fine with me, I look wicked cooler on my bike than they do.
It is fairly easy to maintain speed on flat ground with no headwind, though. Since it’s only a single speed, the pedals provide practically no resistance at higher speeds. The stopping/starting thing probably does help, it takes a lot of effort to force an old bike to start moving, and since I’m always working to get up to speed only to have to stop again, I do work harder overall to go the same distance. I guess I should start measuring distance.
The weight of cargo doesn’t really make much difference? It might be 5 or 10 pounds, or more in the case of my books…
Of course 5-10 pounds makes a difference. It’s how much of a difference we’re worrying about. The fact is, it’s going to be impossible to get anything other than a rough estimate of how many calories you’re burning, and 5-10 pounds of extra weight is unlikely to impact that rough estimate.
There was a 100-odd post thread on a mountainbiking site I look at that was arguing the toss on this issue, does riding a heavier bike give you a better workout? It didn’t really resolve itself, in real terms riding a lighter bike often means you ride faster, longer etc so its basically a wash.
Your cruiser is probably way heavier than 20-25lbs btw, that’s a lightweight mountain bike.
