Table of Contents
The fitter you become, the more efficiently you run, which means the same run burns slightly fewer calories than it once did. But the difference is surprisingly small. Here's how fitness really affects calorie burn and what you can do to increase it if weight loss is your goal.
How fitness changes calorie burn
As your fitness improves, your body needs less energy to hold a given pace. That quality has a name, running economy, and it comes mostly through better neuromuscular coordination, small improvements in technique, more effective elastic energy return from tendons, and reduced unnecessary movement.
The overall calorie savings are modest, though. Trained runners improve their economy by a few percent over months, and beginners sometimes gain closer to 8 percent across a first training block.
Even at that upper figure, a 180-pound (82 kg) runner covering 5 miles (8 km) saves about 50 calories across the whole run, which is roughly half a banana.
Most of the energy a run costs goes into moving your body over the distance, and that requirement barely changes as you get fitter.
How the run feels is a different matter, because the same route may seem much easier than it did a few months ago, with a lower heart rate and fresher legs at the end. Those changes are real and they show your fitness improving, though they say nothing about the calories.
How training changes calorie burn
Although running economy improves, your training usually changes over time as well.
Most runners do not keep running exactly the same workouts once they become fitter. They extend their long runs, increase weekly mileage, add speed work, or move more in general.
Because of that, total calorie burn often increases, even though each individual mile costs a little less than it used to.
How losing weight changes calorie burn
Your body is the load you carry, so a lighter body costs less to move over the same mile.
A 180-pound (82 kg) runner spends roughly 125 calories per mile. At 160 pounds (73 kg) that mile costs about 112. Across a 5-mile (8 km) run the difference comes to around 65 calories, and none of it required any change to your training.
Taken together, if you have improved your running economy and lost weight, you really are burning fewer calories than you were at the start, running the same route at the same pace.
How to burn more
Say you are running to lose weight and progress has slowed or stopped altogether. To raise the calories you burn, you can do the following:
- Add a mile to each run. Two runs a week at 4 miles becomes two at 5. Ten minutes per outing, and the easiest place to start.
- Add a running day. Going from two days a week to three moves the number about twice as far as adding a mile does. Remember to keep a rest day between runs while your body adjusts to the load.
- Put hills in one session a week. Running uphill costs more per mile than flat ground, since you lift your body as well as move it forward. One hard session a week is plenty for most runners, and it needs easy days on either side. If you are carrying a lot of extra weight, build your easy miles first and leave the hills until later.
- Walk or cross-train on your off days. An hour of brisk walking, cycling, or swimming adds to the week without asking anything more of your running legs.
Even so, burning more is only half the equation. Losing weight comes down to a calorie deficit, and you can widen it by burning more, which is what everything above is about, or by eating less. Most runners spend all their attention on training and very little on what they eat.
That is worth reconsidering, because the two are not equally hard. Running off a few hundred calories takes half an hour. Keeping the same few hundred off the plate takes a decision, and it works whether you ran that day or not. So when the scale stops moving, the place to look may not be your training but your meals.
