I ride to and from work 3.7 miles each way, 4 times a day. (School bus driver.) It takes me between 14 and 18 minutes, depending on how motivated I am. What burns more calories, faster, but the ride is shorter; or slower, and the ride is longer? ("Fast" is only about 15 mph.)

I calculate calories burned with the formula: 100 cal for every 5 km.

So if I cover 5 km in 15 minutes ... I've burned 100 cal in 15 minutes.

If I cover 5 km in 20 minutes ... I've burned 100 cal in 20 minutes.

Work is force*distance so unless there are differences in efficiency, the work would be the same.

If you really want to burn calories both during and after your ride, do both. Interval training involves short bursts of intense effort followed by brief rest periods. There are numerous variations but if you have a FitBit or similar pulse monitor, here is a good one: Push hard and maintain 85%+ of your max heart rate for one minute. Reduce the effort to a comfortable pace and let your heart rate come back down to <70%, then hit it again. Do this for 5-10 repetitions to start and then finish the ride at a comfortable pace to cool down. Of course you don't need a heart rate monitor to do intervals, they can be as simple as ride hard for a minute, spin comfortably for a minute and repeat.

Going faster you will always have more apparent wind (actual wind being the same of course), the force against you being nonlinear with respect to speed means you will burn more calories going faster over the same route.

If I'm reading the question correctly, it's something like the "which is heavier" problem. Work is work. If you use 200kJ to do a fast 5 mile ride one day and 200kJ to do a slower 10 mile ride the next, they obviously used the same amount of energy.

Now if you're talking kJ or kCal per minute, then faster always wins.

Regardless of pace, at least for me, 3.7 miles isn't even long enough to get my muscles warm-- so intervals would be out of the question. YMMV.

Yes, the speed penalty is proportional to the square of speed. So twice as fast is 4 times the work.

By extension, and speaking very roughly, riding half the distance at twice the speed is roughly twice the total effort.

BUT LIFE ISN'T QUITE THAT SIMPLE.

For example, we continue to burn calories at a higher level, after a workout stops. This effect is more pronounced (to a limit) with longer workouts, so you may not see that bonus after a short hard ride.

True though at his speed and total time that delta is going to be pretty small.

Before anyone gets picky-geeky, rolling resistance is linear and, say, half of the total force at low speeds so it's technically not all of 4x the force, but this is the gist of it. It's more calories when faster.

It take more force to move a bike faster.

More force = more work.


-Tim-

If you want to burn more calories, just take a detour for more miles! But yes, riding faster will probably burn a few more calories.

About the length of a longer Strava KOM segment. Tear it up as fast as you can, and burn those calories. The end of the day ride would be my fastest, if I were in your situation.

Fast slow...whatever, but how about cadence and gear selection.

What burns more calories..spinning in a low gear at 100 rpms, or grinding in high gear at 60 rpms...same speed.

Thanks for the thoughts and opinions.
I was thinking that, at my pace and distance, there is probably a bit more calorie burn when going faster, based mostly on increased wind drag. Although there is the fact that I perspire more when I ride faster.
It's short rides, so I thought I'd increase the speed as I'm capable. I'm not training for anything. It's more about making the rides more interesting.
It's 74 miles a week. That should keep the ticker working pretty good. Jerry Seinfeld said something to the effect of, "Why's everyone getting in shape? What are they getting in shape to do?" Of course, at 57, being able to ride 74 miles a week has to be doing something good for me. Although my neighbors dad is 99 and he never exercised, and doesn't eat any particular "healthy" diet. ???

If you're driving a bus, and it only takes about 15 minutes, I don't see how driving either slower or faster would burn more calories.

(a) Trained cyclists and triathletes are more efficient and economical when cycling at 60 rpm than 80 or 100 rpm. (b); Local tissue oxygen saturation levels are higher at 80 rpm than 60 and 100 rpm; (c). Heart rate and blood lactate levels are higher with cadences of 80 and 100 than 60 rpm; and (d). Local and global RPE is lower when cycling at 80 rpm than at 60 rpm and 100 rpm. A practical application of these findings is that a cadence of 60 rpm may be advantageous for performance in moderately trained athletes in contrast to higher cadences currently popular among elite cyclists.

https://www.ncbi.nlm.nih.gov/pubmed/22648142

This might help.

Calories Burned By Heart Rate | Calories Calculator

Faster does more, but shifts your energy substrate utilization to use more glycogen and less fat.

Glycogen depletion makes you hungry, with runners calling the phenomenon "runger." Eating just enough to replenish it you may net a few less calories than if you slowed down. Snacking when ravenous can result in a lot lower net than if you went slower.

Excess Post Exercise Oxygen Consumption is real, but not very significant around 10% of what you burn during exercise.

I stopped loosing weight with an extra 35-40 pounds of fat above my ideal riding weight when I made the self-trained athlete's mistake of riding "hard" whenever possible. I was slower too because that means you aren't fresh enough to ride really hard on tough days, and never go slow enough to rely on your oxidative energy system so your endurance pace increases significantly.

1 Watt = 1 joule/second, so 100W for 1 hour = 360,000 joules or 360kj. 1 Calorie = 4.2kj although cycling metabolic efficiency is never better than 25% so you can approximate 4 Calories in = 4.2kj out and round to 1 Calorie in = 1 kj out. On "flat" terrain out-and-back using a power meter with +/-2.5% accuracy I measure about 100W averaging 15 MPH for 360 Calories / hour and 24 / mile; 150W at 17 MPH for 540 Calories / hour and 32 / mile; and 200W at 20 MPH for 720 Calories / hour and 36 / mile.

Rides in the mountains run about 30 Calories/mile.

Larger riders can add a little, not a lot as suggested by on-line calculators.

50 pounds = 22.7 kg

22.7kg * 1604 meters/mile * 9.8m/s^2 * .004 Crr = 1427 joules = 1.4kj = 1.4 Calories/mile from 50 pounds more

Small mountains are about 2000 feet or 600 meters high
22.7kg * 600 meters * 9.8m/s^2 = 133 Calories.

The force from aerodynamic drag is proportional to the square of velocity.

Ummm.


57 ± 9% followed by 54 ± 9% and then 55 ± 11%.


Numbers within 4% of each other with accuracy ranging from plus minus 9% to 11%???


Is this study even valid?

That's garbage.

In good shape I'm good for about 550-600 Calories/hour riding a 17-18 MPH endurance pace on flat ground at 137 pounds and a 140 bpm heart rate versus 350-400 at 15 MPH on flat ground weighing 200 pounds with a heart rate approaching 150.

Wind resistance and rolling resistance (tires and drivetrain). Here's an example chart.

At 20 kph (12 mph), rolling and wind are each about half.
At 30 kph (19 mph), or 40 kph (25 mph) wind resistance goes way up compared to rolling resistance.

From the chart,
A 20 km ride at 20 kph is around 90 watts for an hour (add the two lines together.)
A 20 km ride at 40 kph is around 340 watts for a half hour.

Faster or slower doesn't really mean that much. There are a few variables to consider. You might coast a bit after pedaling fast, as opposed to just maintaining a constant, but "slow" speed. OTOH, you might be going uphill one way, but downhill the other way. Uphill and against the wind always requires more work! More work requires more energy. Therefore, more calories get burned

Faster means more wind. Faster is more work.

OP: Go faster.

Those Are SD bars, the p values tell you statistical significance. Here's another study