Among the many ways to improve your running performance, “running economy” seems like an especially abstract, difficult-to-train idea.
But it is actually a critical metric. Running economy is especially important to more advanced runners, and those who are already at or near their peak possible fitness. Understanding it, and learning how to measure it and what affects it, can be a valuable tool in your running performance arsenal.
Once you know your own running economy, you’ll have a tangible number that you can work on improving.
If you haven’t already been using running economy as a measurement of your performance and you want to start, this article will tell you all you need to know.
Let’s get into it!
What is Running Economy (RE)?
Running economy (abbreviated RE) is a measure of how well your body converts oxygen into activity.
That may sound complicated, but in simple terms, it’s the amount of oxygen your body needs to sustain a specific speed (below your maximum) when you run.
With every step, you use oxygen. You breathe in, and that oxygen gets into your bloodstream and into your muscles, providing energy. It also helps break down the protein, carbs, and fats in your system so energy is readily available.
The less oxygen you use to run a particular speed, the better your RE. Less oxygen means less strain on the body; you won’t be breathing as heavily, and your body won’t be working as hard to convert food to energy and keep you going. It can simply focus on running.
If you’re new to RE, it may be a little confusing that the lower the number, the higher your running economy.
Think of it like our money spending economy – the less you pay for something (the lower the number), the better!
RE as a Fitness Metric
Running economy is probably the least well-known of the advanced running metrics. VO2 max and lactate threshold are the two better-known ones.
But running economy is the third leg of the tripod if you’re after improved performance. It’s particularly important for distance running, as it’s a great indication of stamina over a long period of time and distance.
What are VO2 Max and Lactate Threshold Again?
VO2 max, lactate threshold, and running economy all work together.
VO2 max is also known as your aerobic capacity. It’s the volume (V) of oxygen (O2) that your body can absorb per minute when you’re exercising. This metric is measured in milliliters per kilogram of body weight per minute (ml/kg/min).
Sometimes, you’ll find it measured in ml/kg/km. Remember, one pound is approximately 0.45 kilograms.
For VO2 max, the higher the number, the better. You want to be able to take in as much oxygen as possible, as this transports nutrients through the blood and into the muscles and brain to fuel metabolism and improve your performance.
Lactate threshold is a measure of the intensity of exercise at which lactate builds up in the body faster than it can be removed.
The body breaks down glucose as a matter of metabolism, and one byproduct is lactic acid. As exercise intensity ramps up, the lactic acid starts to break down, and lactate is the by-product.
When the body can’t filter this out fast enough, it can cause nausea and possibly vomiting. At this point, you’ll need to stop and allow your body to sort itself out before you continue.
This point is your lactate threshold, and it is determined loosely by the rate at which your body burns oxygen. If yours is high, your body can go for longer at high intensities before hitting that ceiling.
How Do You Track RE?
Tracking your own running economy can be a little complicated. Currently, smart watches don’t have a running economy function.
In order to find out your running economy, you’ll need to get some tests done in a lab. There, they’ll have the necessary equipment to measure just how much oxygen you’re taking in and how much is being used, which you could never measure yourself (and certainly not with a watch. Your watch’s VO2 max reading is also a calculated estimate, not a true measurement).
In the lab setting, your VO2 max is measured, as well as something called your Respiratory Exchange Rate. Between these two, your RE can be worked out, and you’ll be given a number.
Unfortunately, this is the only way to track it. You can’t compare it day by day or week by week as you would your speed or distance (unless you go get lab-tested every week).
If you understand what your RE is and what affects it, you can still work towards boosting it without having the metric on your smartwatch or running app.
Variables That May Affect Running Economy
VO2 max and lactate threshold are largely determined by biology. They can be trained, but only so much. Running economy, on the other hand, is largely mechanical and can most definitely be improved. It can change day to day, but it won’t necessarily change by much unless you’re struggling with a cold or something that affects your breathing significantly.
But it can be affected by little things that occur during your run. The terrain you’re on, the shoes you’re wearing, and even the weather can influence it.
Some things that may cause your RE to fluctuate slightly include:
Your Vertical Oscillation
This is how much your torso moves up and down when you run. You may wonder why this is significant, but if you’re moving upwards more than you’re moving forwards, your RE will be less. Fast runners are rarely “bouncy” runners. Rather, they have perfected a stride that pushes up just enough to maximize stride length without looking like they are bounding down the road.
How Fatigued Your Muscles Are
The muscles’ ability to absorb energy during the foot strike and return it to push off again can be helpful or detrimental to your running economy.
If you’ve had good sleep and your muscles are feeling strong, your RE will be better. If they’re feeling tired, your RE will most likely suffer.
Your Running Form and the Type of Running You’re Doing
Incorrect running form can put more strain on the body, causing your running economy to decline. Leaning too far forward, sitting too far back, swinging your arms side-to-side, and a cadence that is either too fast or too slow can all contribute to decreased efficiency.
Also, your RE is likely to change depending on if you’re doing your usual kind of running (long distance, sprints, etc), or if you’re doing high-intensity training or trying something different.
As your general fitness level improves, especially cardiovascular fitness, your running economy will improve too. Cross-training can help to pick up your fitness level and boost your RE.
As we grow older, our bodies slow down. It’s a fact of life! If you don’t take particular care to maintain your VO2 max and fitness levels as you age, it can be harder to keep your RE where it once was.
What You’re Wearing
Wearing shoes that don’t quite work for you, heavy clothing, or even just clothing that’s uncomfortable can affect your RE. On the other side of the coin, wearing the right stuff can improve it.
When Nike introduced the Vaporfly 4%, they made the shocking claim that the shoes improved running economy by up to 4%. Lab tests showed this is, well, kind of true, more or less, for some runners. The most recent iteration of the line, Alphafly NEXT% (the shoe Eliud Kipchoge wore to smash the marathon record and run a 1:59:40), has the same features that make them pretty much guaranteed to boost your RE.
Heat or cold can affect your running economy, too. And it doesn’t even take much deviation at all from an “ideal” running temperature (somewhere around 55-60F) for your efficiency to suffer. Go to extreme temperatures, such as above 80 or below 30, and the difference will be substantial. Wind, rain, and even wet roads can also influence it.
How Can You Boost Your RE?
The good news is that even though RE fluctuates, there are things you can do to boost your running economy and improve your performance.
Increase Training Volume
The more you run, the better you’ll get! Like anything, practice makes (closer to) perfect.
There are two ways you can do this. One, increase the number of runs you go for in a week. Or, two, add distance to your runs.
If your running schedule is 5 runs a week of 5 miles each, you can either:
- Do 6 runs a week of 5 miles each
- Do 5 runs a week of 6 miles each
Either way, at the end of the week you’ve now run 30 miles instead of 25. Try to do this every few weeks, and you’ll find your RE improving quickly.
Incorporate Uphill and Flat High-Intensity Intervals
If you’re training for something like a marathon, you may be used to running a great distance, but on a fairly flat surface.
Incorporating interval runs and incline training can make a huge difference. Instead of just running at a moderate pace on a flat surface, add short bursts of speed (eg. for 100 meters, or 30 seconds).
This increasing and leveling out of the heart rate improves cardiovascular performance, which in turn boosts VO2 max and RE.
For an easy way to begin adding these to your training, try 10 x 200m sprints with 100m of jogging in between. If you need something more basic, try 10 x 200m jogs with 100m of walking in between.
Strength and Stability Training
Cross-training improves overall fitness, which improves running economy as it ups cardiovascular strength and reduces the amount of energy needed for metabolizing protein and carbs.
You don’t need to go to the gym 5 times a week. Just 1 or 2 strength training sessions per week is enough to start getting the benefit.
In plyometrics (or jump training), you exert the maximum force your muscles can manage for a very short interval. It’s kind of the opposite to endurance-style training.
The goal of plyometrics is to increase power. You can add a couple of plyometric exercises to your regular strength training, or just do them by themselves a few times a week.
Box jumps, squat jumps, and side jumps are good ones to start with.
The higher up a mountain you go, the thinner the air gets. And the thinner the air gets, the harder it becomes to get enough oxygen into your lungs.
Training regularly at a higher altitude can kick off specific metabolic functions of skeletal muscle that actually help the body to use oxygen more efficiently.
That way, once you land back at a lower altitude, your body can utilize oxygen extra efficiently, without the stress of thin air. Most endurance athletes choose to live at higher altitudes for this reason, whether that’s Flagstaff, Arizona or Eldoret, Kenya, or somewhere else.
Get and Maintain a Healthy Body Mass and Body-Fat Percentage
VO2 max is not the same as running efficiency, but they are closely related. And one aspect of VO2 max is mass, or body weight. Carrying excess weight means your running economy will suffer. Simply put, you are working harder to move more mass, much of which is not directly involved in the running. The stress placed on both the lungs and the rest of the body doesn’t facilitate a great VO2 max.
Shedding those extra pounds can help increase your pace, take the pressure off your joints, and improve your breathing. The same amount of muscle has less mass to move. Therefore, it will be more efficient.
It is easy, however, to take this advice to an unhealthy extreme. You do not have to look too far to find stories of runners who have developed eating disorders in an unhealthy pursuit of lower weight at all costs. Both their health – mental and physical – and their performance suffer. When you are dangerously underweight, your body may also struggle with the amount of stress running places on it. This will keep you at a worse RE until you put on some muscle.
Improve Running Form
If your running form is off, your running economy could be too. Everything from the way your feet land on the footstrike to how much you engage your core while you’re running influences the energy you use and how much O2 you end up taking in.
Getting your running form right is a good idea for many reasons, including increased performance and less chance of injury. But it can also boost your RE significantly.