I’m house-sitting my mothers house in the country
To get to work I need to cycle 15 km and 15 km back
In the morning it takes me 35 minutes to get to work and 45 minutes to back at the end of the day.
There are a few hills but they go both ways, the difference is mostly because at the end of the day I’m tired and don’t feel I need to ride as fast.
Do I burn the same amount of calories both ways?
Close, but not exact. The faster you go the more wind resistance you have to overcome, and it isn’t a linear increase. Doubling your speed increases your wind resistance by a factor of 4, roughly. Changing your position on the bike has a huge effect on that as well, and you may be in a more aerodynamic position when you are riding faster.
So ride faster=more resistance=burn more calories?
Yes.
Also, unless the climb/decent is the same, you’ll burn more on the “uphill” leg of the round trip.
There are two hills but both locations are on the same elevation
Oh and what if I did the same distance with different speeds on a treadmill?
…and what if I’m pushing an unladen 747 for half an hour, then a fully laden 707 for the next half hour so they weigh the same…
IAMNA Expert in nutrition or similar, but I notice when cycling with a low speed (around 10-15 kmh) my heart rate and sweat production is much lower than when I’m cycling fast (above 20 kmh). So at least anecdotal, there’s normal calorie burning and high burning because only my legs are working vs. my whole circulation system is in overdrive.
Have you tried measuring your pulse on both occasions? It’s the first rough guide on how much you’re burning.
In both cases you are accomplishing the same “work” in terms of moving a certain body of mass a certain distance, but you are likely doing so at different efficiencies. The effect is likely less for the treadmill example than for the cycling one. Still walking at a slower speed is more efficient biomechanically than moving more quickly; moving a distance quickly burns more calories than moving that same distance slowly.
The different effects on weight loss and on body composition* given the same amount of calories expended* is a separate subject.
There is an excellent bicycle calculator at http://www.kreuzotter.de/english/espeed.htm
For most bikes, at 25 kph you are using around 170% of the power needed to go 20kph.
Since you are riding for a shorter time at the faster speed, total calories burned at 25kph is about 140% of calories burned at 20kph.
I was going to say it’s obvious that the rate of energy consumption depends on the speed one is maintaining, but I get the sense that you’re implying that exerting yourself increases the rate significantly above and beyond that implied by a simplistic analysis of the physics involved.
I concede that might very well be true, but I really doubt you have so fine tuned a sense of your body you’d be able to tell.
What I tried to express that it’s not a linear equation of speed x = y calories, speed 2x = 2y calories, because the human body works differently.
If you start exercise, under normal circumstances the body starts with anaerobic burning because the body doesn’t want to gear up, it thinks “this will be over soon”. If you keep exercising for the famous 30 min.s (or 45 mins, depending on what you’re doing), your body thinks “well this is going to take long” and switches to aerobic burning. This initially requires a higher energy but once it’s going is more efficient. Also it produces no lactic acid (part of sore muscles), and (importantly) burns fat instead of sugar.
But it also depends on the type of exercise. If you run/jog 10 mins., your whole system is doing very different from taking a leisurely walk for 30 min.s. The easiest way to measure this is pulse.
A doctor in a lab can measure much more by looking at the contents of what you exhale (how much CO2 => what kind of burning process), or the amounts of stuff in your blood, so if you really want to know, go to a lab on a stationary bike/ treadmill* and see how your specific body works, at what point it switches types, what pulse rate is optimal for you etc.
Usually, that’s not worth the bother unless you’re a top athlete or a science journalist doing a report on this, or part of a study.
are there gyms in the US who offer this service?
I live in Holland btw
Simple physics tells us that the rate of energy consumption will be different in these two scenarios, and measuring your pulse just tells you that yes, it is. But simple physics also tells you that the work done will be the same, because the higher intensity is in reverse proportion to the shorter time. Which is only true for high school physics problems, but is a good approximation a lot of the time.
Wind resistance will certainly upset this simplistic calculation if the speed difference is high enough, and I’m sure the human metabolism isn’t a linear function of speed either. The question is how wether it’s sufficiently off a linear function to make a difference in this scenario, and “you get more winded when jo jog than when you stroll” doesn’t tell us anything. Not that I think that’s what you’re implying, but do you have any references that indicate how much human efficiency changes with various rates of work?
I also wonder whether the non-linearity works to make high intensity / short time excercise burn more calories or less than the low intensity / longer time geographical equivalent.
I would hazard that aerobic exercise and anaerobic exercise burn calories at far different effieiences. Some rudimentary searching pulled websites that seem to agree, but nothing was really good enough to link here. If this is correct, if the two routes cause you to use different pathways to get the same amount of energy out of the system (moving from A>B and B>A) the more efficient method of getting that energy to the pedals will require less input chemical energy and burn fewer calories.
Already established: Bodies move with different efficiency moving in different manners. We are evolved to be very efficient walkers. We can literally walk all day. Running is something that we did briefly during that evolutionary timescale, to capture prey or to avoid being prey, both worth spending excess energy to do.
In terms of the relative efficiencies of aerobic vs anaerobic metabolism - aerobic is more efficient. This study analyzed the question with a stationary bicycle and found that efficiency was significantly lower at anaerobic threshold than at aerobic threshold. Thus the same work (distance traveled) at an all out sprint burn more calories than a more leisurely pace for metabolic reasons in addition to biomechanical ones. For those in condition and of the mindset to do that.
I was under the impression that chasing animals for long distances, to drive them to exhaustion, was one the first methods of hunting ever used. The idea seems to be that other animals can only run for quick bursts, and then they need time to relax. The hunter would catch up to them during this break, which would be cut short as the animals needed to run again to escape the hunter. The breaks the animals take isn’t long enough to totally regroup, and so eventually, they collapse from fatigue, and then the hunter smashes them with a rock. This process, as you might imagine, requires the hunters to run for hours on end. So, I don’t think it’s true that running is only a sometimes thing for humans. A full out sprint is rare, but slower running isn’t, I don’t think.
There might also be the issue of increased muscle mass from increased exertion rates, which would slightly increase your base metabolic rate even when not exercising.
Otara
You should remember that the body has two different goals of efficiency: anaerobic burns sugar (carbohydrates), which is quick, and therefore the default for sudden, short-time movement. So in terms of efficiency for time, this is better than the other method.
The downside is that this burning process accumulates lactic acid*, and that sugar doesn’t have as much calories as fat, so you burn more stuff to get energy.
aerobic burns fat, which gives more energy, and is therefore more efficient for long-time movement. But it has the downside of taking some time to warm up to and needing an initial investment to get the cycle started.
Because both adress different aims, the body uses both.
When people exercise, instead of escaping a lion or hunting a gazelle, they usually have two aims in mind: increasing general fitness by improving cardiovascular system; and burning fat, which is the problem. Therefore, you want to get into the aerobic burning zone regardless of “physical efficiency” if you want to burn fat.
Some basic wikipedialinksabout the concepts. With a graph about the different forms of exercise.
Then, other scientists found micro-rips in the fibers of the muscles themselves, and declared that the cause. Therefore, the recommendation was enough rest so that the muscles could heal, and that people shouldn’t overdo their exercise to avoid the tears in the first place.
Now the consensus seems to be that both contribute to sore muscles, and how much each depends on the individual circumstance.
Not sure who I should quote but I recently read an article that claims that it is a myth that walking and running burn the same calories per mile – Runner's World
I recall an issue of Scientific American discussing the physics of cycling. They pointed out that the upper speed limit of even an athletic rider was around 35 to 40mph, since wind resistance became the dominant factor at higher speeds. OTOH, there was one experiment where they had a full plastic cage over the cyclist (behind a truck) so essentially there was no wind resistance, the air moved with the cyclist. Good athletes could easily attain speeds in excess of 60mph.
