I'm thinking of taking part in a cycling event, I'd like to do something that's about as challenging as running a half marathon (13 miles / 21 km). Approximately what distance should I be looking at?
I think in principal this could be worked out with a heart-rate monitor (if I had one):
I know calorie counts vary quite a bit, but a rough ballpark for cycling at a 20 mph pace is 450 calories per 15 minutes according to this calorie calculator.
Running a 6 minute mile is expected to burn a similar 450 calorie count on the same calculator with the same settings.
So, if you do the math, and the calculator is assumed to be reasonably accurate, then 5 miles on a bike at 20mph, is roughly equivalent to 1 mile run at a very fast pace.
Running a half marathon, which is 13 miles, and ignoring any difference due to endurance of effort, 13 miles at full pace running could be assumed to be a similar effort to 65 miles on a bike, in a very general sense.
This is dependent on fitness, body weight, and many other factors.
The best method to work it out would be to measure power expended, but I don't know how to do that for running, and to be accurate, you'd need to do it yourself, and for the full distance of the half marathon.
Cycling is different that running in that with cycling you can recover energy while riding and also expend far more amounts of energy when climbing that you do when running.
The rule of thumb in equivalence we talk about in our triathlon group is this:
1/2 marathon ~ 50 mile ride or metric century (100km/62 miles) depending on amount of climbs Full marathon ~ 100 mile ride
Cycling is much easier on the joints and rides usually have stops to eat, drink, pee, etc.
Cycling is harder than running when it comes to getting a good fit on the bike and getting flexibility in the different body parts to feel relaxed on the bike for hours on end.
Good luck!
The distance does not matter at all. What matters is the % of Heart Rate Max vs Time
The goal in training, whether running or cycling, is to achieve and maintain a specific HR range for some amount of time. That number is not directly related to distance.
Hypothetical example for a cyclist getting back into the swing after a winter of sloth...
Distance is irrelevant. The idea is to think about intensity. At least for training/workouts. Otherwise it doesn't matter.
So getting back to the main question: How much easier is cycling compared to walking or running?
Way easier or can be. FWIW...my bike commute is far less effort than walking to work. That's why I do it. On the other hand, with intense interval training, one or two cycling miles can be quite difficult.
@hhhh
wdypdx22: how do you measure % of HRMax? Any cheap way to do that like approximating somehow while riding?
3 ways that I know of to determine Max Heart Rate:
Another method is RPE (Rate of Perceived Exertion)
The goal, which is a % of the Max Heart Rate is easily calculated. No one needs my input.
We have all been cycling up a hill at a 'snail's pace' to be huffing and puffing, sweating out of every pore, with heart mouth, to pass pedestrians/joggers that are making good progress without showing any signs of being on the verge of a heart attack.
Arguably half-marathon by foot in flat terrain is going to be approximately as challenging as 13 miles cycled up an Alp. Therefore you are not able to compare apples and banana here, there is no distance or time comparison you can make. However, as a rule of thumb, cycling is four times as efficient as walking.
A lot of sportive events around here send you up and down the big hills and the hills with challenging gradients. Although there is a descent for every ascent you don't make up on the freewheeling what you lost on the agonising climb.
Some cycle events offer a variety of courses, you can sign up for the easy event and, part way through, if you are feeling good, take the full course loop.
The Wiggle 'Dragon' event in South Wales the other week has the difficult 'valleys' it also has the extended loop. The middle 120km distance in that terrain is more like your half marathon, the 200km more like your full marathon.
If I use the calculator at http://www.prohealth.com/weightloss/tools/exercise/calculator1_2.cfm at a weight of 165 lb then for bicycling at 14-16 mph "vigorous effort" it gives 750 calories/hour.
To spend 750 calories/hour running you need to run at 6mph (10 minute mile).
So at that level of effort (750 calories/hour), to run 12 miles would take 2 hours, during which time you could cycle 30 miles.
Personally I'd find the running more challenging.
If you can run a half marathon, you probably have a nice endurance, that's good.
However different sports use different muscles in different ways. So, say you run a half marathon in a bit more than 1 hour...
If you do an effort of the same intensity (which is very intense) on a bicycle for an hour, and you're not used to cycling :
So the only way to know is to try !
There is an excellent chart by R Chung in another question on this site How many miles of riding require the same effort as one mile of running?. His chart basically comes down to a ratio of 2.5 to 3.5. So if you are running at a speed of X per mile, then 13.1 miles of running is roughly equivalent to 32.75 to 45.85 miles or about 39.3 bicycle miles.
