Last Updated on November 4, 2022 by Heather Hart, ACSM EP, CSCS
The endless jargon associated with running workouts can be confusing to runners at times. For the most part, the majority of us seem to understand prescribed efforts. We know what our “5K race pace” feels like, we understand a “10/10” sprint effort. Or in the case of ultrarunners, we certainly know what our “all day pace” is.
But if someone tells you to run at tempo run pace…do you know what that actually means? Do you wonder if it’s something you should be doing? Or if tempo running workouts are even useful for longer distance ultrarunners?
Believe me, I get the confusion. Looking back, I probably spent the first few years of my running career thinking I knew what “tempo” meant, but not being 100% sure.
(And it’s no surprise…if you ask your local running group to describe “tempo running pace”, you’ll probably get a half dozen different answers).
My goal in writing this post is to help you understand WHAT a tempo run is, why tempo running workouts can be beneficial for runners (from half marathon to ultramarathon distances), and how (and when) to add them into your training.
What is a Tempo Run?
In short, tempo running workouts or “tempo runs” are workouts done at an intensity just below or at your lactate threshold, with the purpose of improving your lactate threshold.
“Wait…what’s a lactate threshold?” you might be wondering. Don’t worry – per usual, before we get to the benefits of tempo runs and how to do them, we’re going to dive into a little science (my favorite part!)
“Ugghh…not Heather rambling about science again!” I get it, I do. Click HERE to skip ahead to the practical “Incorporating Tempo Workouts into Ultramarathon Training” section. Or, stay with me to learn more about how your body runs!
Lactate & Lactate Threshold Explained
I’m fairly confident that if you’ve been around the running world long enough, you’ve heard the terms “lactate”, “lactic acid”, or “lactate threshold” thrown around. And if you haven’t…well you’ve heard it now. And while many of you might be familiar with the effort or associated pace of your “lactate threshold”, you might not understand what it means on a physiological level.
I’m going to break this down in what hopefully comes across as an easier to understand explanation of what can be a complex topic.
In order to do – basically anything at all – our bodies need some sort of fuel to use as energy. Cellular respiration is the process by in which our bodies break down sugar (from the foods you eat) and turn it into adenosine triphosphate (ATP). Think of ATP as the body’s useable form of energy. ATP is then used to perform work at the cellular level (i.e. “do” all of the things your body needs to do to continue living). There are a couple of pathways that can occur for cellular respiration to happen.
The aerobic respiration pathway creates large amounts of energy, utilizing all three macronutrients (fats, carbohydrates, and protein) as a fuel source. This process is slow (relatively speaking) and requires oxygen.
The anaerobic respiration pathway consists of two systems: the Phosphagen (immediate) energy system and the fast glycolytic pathway (glycolysis). These both produce energy quickly, but in limited quantities. They use the energy contained in glucose for the formation of ATP, and no NOT require oxygen.
(For the purpose of this blog post, we’re going to ignore the phosphagen system for now.)
When you’re cruising along, running at an easy pace, you are utilizing the aerobic respiration pathway. But say you decide to suddenly sprint up a big hill. This effort is going to recruit more muscle fibers, and require more energy. Thus, your body needs more oxygen. So you start breathing harder and harder, but eventually you reach a point where you simply cannot bring in enough oxygen to meet the demands of energy production.
At this point, your body switches to mainly utilize the fast glycolytic pathway, or anaerobic respiration in order to keep up with energy demands (note: there is no on/off switch where your body is only using one energy system. But during harder intensities, your body is predominately using anaerobic means of energy production).
Where Does Lactate Come In?
The end product of glycolysis is pyruvate. Pyruvate then is either shuttled into the mitochondria to be recycled into energy during the aerobic respiration (in the presence of oxygen), or it is converted to lactate in the absence of adequate oxygen.
Initially, the liver will take in lactate for conversion again to glucose, allowing energy production to continue. The working muscle cells can continue this type of anaerobic energy production at high rates for one to three minutes, during which time lactate can accumulate to high levels in the blood.
But, during intense exercise when there isn’t enough oxygen present (and after the one to three minutes mentioned above), the amount of lactate and hydrogen ions in the blood increase at such a rate that the body can’t clear them fast enough
And the point when your body can no longer clear lactate and hydrogen ions from your blood fast enough to maintain homeostasis? That’s your lactate threshold. For most athlete’s, it’s typically around the point when lactate volume in the blood reaches 4mmol/L (“millimoles per liter”). While scientifically speaking, the lactate threshold is determined through a blood draw in a lab setting during exercise, athlete’s can usually sense they’ve reached that point by experiencing:
- Burning muscles (though, please note, lactate is not responsible for this!)
- Feeling like you might vomit
- Overall sense of fatigue (you can’t continue to keep up that effort/pace)
Surpassing your lactate threshold is not necessarily a guaranteed way to crash, burn, and DNF your race. Again, as mentioned above, there is no on/off switch where your body is only using one energy system, and there is almost never NOT oxygen present. If you slow down your effort to the point where the demand for oxygen from your body lowers enough to help reestablish homeostasis and the ability to properly clear blood lactate levels, you can keep going.
But if you don’t lower your effort, eventually, your body will force you to stop running.
Are Lactate Threshold and VO2 max the same thing?
Not quite. VO2 max, often referred to as maximal aerobic capacity, is the maximum amount of oxygen your body can take in and use during exercise And as we just established, lactate threshold is a determination of the point at which lactate (a chemical byproduct of anaerobic respiration – the process by which cells produce energy when oxygen isn’t available) cannot be cleared as fast as it is accumulated.
Even though they are different, it’s important to note that lactate threshold occurs at a percentage of VO2 max (typically LT occurs at 70-80% of VO2 max, but this can vary by individual). The amount your lactate threshold can increase is dependent upon the ceiling of your VO2 max. Therefore, it’s useful for runners looking to improve their performance to focus on training both systems.
Learn more about the how and why of VO2 max interval workouts in the post “VO2 Max Interval Running Workouts for Ultrarunners: Why and How to Incorporate Intervals Into Your Training”
Will Tempo Runs Make You Faster?
Bringing this all together now, the purpose of a tempo run is to increase your lactate threshold, which means you can run faster and/or harder, for longer, before your body enters anaerobic respiration, and begins to slow down (or totally crash and burn, as the case may be).
The adaptations your body makes to tempo run efforts includes increasing the size and density of mitochondria (where aerobic respiration takes place) in your muscles, which in turn improves your ability to not only process lactate in the blood, but utilize lactate as fuel.
The Benefits of Tempo Runs for Runners:
But there’s more! Tempo run efforts can also:
- increase plasma volume, giving you greater ability to manage your core temperature
- increase mitochondrial enzyme activity, helping you produce ATP (energy) faster
- help improve speed. Tempo pace is much faster than the everyday, base building, “easy” pace many runners enjoy. As with any exercise the more we practice it, the better we become at that task (in this case, running faster).
- Help improve mental toughness. These workouts are hard, and the last quite a bit longer than shorter interval sprints. You really have to dig deep to be able to hold a tempo pace for the prescribed longer durations (anywhere from multiple 8 minute intervals to 40 minutes continuous)
Are Tempo Runs Beneficial for Ultrarunners?
I can hear it now: “But I’m an ultrarunner, that easy ‘all day pace’ is what matters. Why should I care about lactate thresholds and tempo runs?” That’s a very valid question, and I completely understand why one would ask.
By training to raise your lactate threshold, you are also increasing your aerobic threshold, or the uppermost limit of exercise when the production of energy starts to become dominated by anaerobic glycolysis intensity, and at which lactate just begins to accumulate above the resting level.
More simply put: increasing your lactate threshold means you can increase your “all day pace”, running faster and harder while still remaining in the aerobic zone. Hello, ultramarathon P.R.’s!
How Do I Determine My Lactate Threshold for Pacing Tempo Runs?
So all of this sounds great, and you’re ready to give some lactate threshold workouts a try. But…how do you know YOUR lactate threshold? There’s a few ways to determine this number:
In an exercise science lab, lactate threshold is measured by drawing blood at intervals during an incremental exercise test. This test is performed in a similar manner to VO2 Max testing ( it pushes you to exercise at a HARD intensity) and uses either a treadmill or stationary bike. The exercise intensity is increased in periods of about 3 minutes and blood samples are taken at the end of each period.
If you have access to a lab VO2 max test but NOT the blood draw test (which occasionally happens, due to the qualifications of those administering the test), a number of other parameters can be used to determine your Lactate Threshold from your VO2 max reading. In general:
- The average person reaches their lactate threshold at ~50-60 percent of their VO2 max
- Recreational athletes reach their lactate threshold at 65-80 percent their VO2 max
- Elite endurance athletes reach their lactate threshold at 85-95 percent their VO2 max
Don’t have access to an exercise science lab? You aren’t alone! Fortunately, there are a number of field tests you can administer to yourself, by yourself. No, they won’t be as accurate as a blood draw in a lab, but they are often better than guessing, or using calculations based on the outdated “220-age” max heart rate equation alone. Examples include the VDOT Method, the 3,200-Meter Time Trial, the 30-Minute Time Trial, the Conconi Test, and more.
Personally, I prefer the 30 Minute Time Trial test, as it’s easy to administer (even from afar, for my virtual clients) and studies have shown that estimations of both lactate threshold heart rate and pace were not statistically different from those determined from blood draws. (McGehee et al., 2005)
Find your lactate threshold pace and heart rate using the instructions in this post: Running Lactate Threshold Test: 30 Minute Field Test Protocol
Predictions Based on Existing Data:
You can estimate your lactate threshold pace and heart rate by using data you may already have. Such as:
Pace estimates: Many coaches will say that lactate-threshold pace is about 10 to 15 seconds per mile slower than 5K race pace (or about 10K race pace) for slower runners (slower than about 40 minutes for 10K).
The problem with this approach? Not everyone – (especially if we are talking about ultramarathon runners, which make up the majority of this site’s readers) have truly “raced” a 5K or 10K with an all out, 100% effort. Or if they have, those races were long enough ago that they are no longer an accurate depiction of current fitness.
Heart rate estimates: Most experts agree that in general, tempo effort is approximately 85-90% of max heart rate for the majority of athletes.
The problem with this approach? How many runners truly know their max heart rate? Unless you’ve had a lab test done, chances are pretty good that what you think is your max heart rate is just an estimate.
Therefore, the problem with using simple calculations to give us estimates of lactate threshold pace or heart rate, is that we are using estimated data to estimate even more data, with calculations created based on the general population. This leaves a ton of room for error.
While a field test is still not as accurate as a blood test, we are getting a much better picture of what YOU are capable of and how YOUR body reacts, in real time.
How Hard Should Tempo Runs Be?
Tempo runs, while performed at an effort easier than VO2 max effort, are still hard. To give you an example, tempo pace is typically described as an RPE of 8 or 9 out of a 1-10 scale, whereas VO2 max effort is closer to a 10/10.
So while we can hold a tempo effort for longer than our shorter, hard intervals, we still can’t hold them for hours on end.
(Personally, I find tempo runs to be HARDER than VO2 max intervals, because they require me to hold that uncomfortable pace even longer!)
What is the Difference Between a Threshold Run and a Tempo Run?
Technically, a tempo runs is one single running effort (steady state workout) done at your tempo pace (or, just below or at lactate threshold). Lactate threshold intervals are intervals of running at tempo pace, paired with shorter bouts of rest to help you achieve more training time at tempo effort.
If you remember in my previous post about VO2 max intervals, the purpose of running intervals is to maximize the body’s exposure to stress at a given intensity. Because harder intensities can only be sustained for shorter amounts of time, repeating the intervals gives us the opportunity to log a larger combined total time at the desired intensity. And that accumulated stress, when done properly, results in physical adaptations
How Long Should Tempo Runs Be?
The general recommended time at tempo intensity (either in one shot as a tempo run, or cumulative between multiple intervals in a given workout) varies. I’ve found everything from a minimum of 30 minutes to a maximum of 90 minutes. Of course, on the higher end, it is almost certain that the 90 minutes will be broken up into intervals.
Recommended Tempo Run Interval & Recovery Ratio:
If you are breaking your tempo running workouts into intervals versus one steady state tempo effort, you’ll want to time your recovery intervals appropriately.
A quick internet search will reveal that there are endless approaches to recovery ratios when it comes to tempo/lactate threshold intervals. You will see recommended recovery workout ratios that are all over the place, from 15-30 seconds, all the way up to 5, 6, 7 or more minutes.
Keeping in mind that the purpose behind intervals is to maximize time at intensity, we want our rest intervals to be long enough to insure that during subsequent intervals, you can still reach that desired intensity. However, you want to keep the overall stimulus high to achieve the desired adaptation to the workout.
That said, I tend to agree with the thought process behind a 2:1 recovery ratio. For example, if I’m running 12 minute tempo intervals, I will want to pair that with a 6 minute recovery interval in between.
Examples of Tempo Running Workouts:
Because the concept of the Tempo Run has been around for quite sometime, there are endless approaches to tempo running workouts. Some are complex and hard to keep track of, while others are pretty simple and straight forward.
I recommend the straight forward approach. Pick an appropriate duration for your tempo run, and sandwich it between a warm up and cool down period. Or, choose an interval interval, and repeat it a couple of times, with a recovery (run or walk) in between equaling half the time of the tempo interval. Include a warm up and cool down, and make sure your time at temp intensity doesn’t exceed an hour (less for beginner athletes).
Beginner Tempo Workout:
New to tempo runs? Start here.
- Begin with a 1 mile warm up at your perceived “easy/warmup” pace (Z1 to Z2 if you use heart rate)
- Run 20 minutes at or just below your lactate threshold pace or heart rate
- Cool down with 1 mile at your recovery pace
Beginner LT Interval Workout:
- Begin with a 10 minute warm up at your perceived “easy/warmup” pace (Z1 to Z2 if you use heart rate)
- Run 3×10 minutes at tempo pace, with 5 minutes recovery (so, 10 mins tempo/5 mins recovery/10 tempo/5 recovery/10 tempo/5 recovery)
- Cool down with 10 minutes at your recovery pace.
Total workout time: 65 minutes
Total time at tempo effort: 30 minutes
Intermediate Tempo Workout:
Comfortable with temp pace, and in the middle stages of your ultra training (meaning, you need to keep volume in mind)? Give this try:
- Begin with a 2 mile warm up at your perceived “easy/warmup” pace (Z1 to Z2 if you use heart rate)
- Run 4 miles at or just below your lactate threshold pace or heart rate
- Cool down with 1-2 miles at your recovery pace
Intermediate LT Interval Workout:
- Start with a 20 minute warm up at your perceived “all day” pace (Z2)
- Run 3 or 4×12 minutes at tempo pace, with 6 minutes recovery between
- Continue with 20 minutes at your “all day” pace.
Total workout time: 1:34 – 1:52
Total time at tempo effort: 36-48 minutes
Where In an Ultramarathon Training Cycle Do Tempo Runs Fit?
Let’s refer back to the post on VO2 max intervals. There we discussed that in order to raise your lactate threshold or even your endurance capabilities, you must first raise your aerobic capacity, in order to allow these other improvements to occur.
Further, we talked about the specificity of ultramarathon training should be the focus during the latter stages of a training cycle. Thus, placing VO2 max intervals are best done during the early stages of a training cycle.
Therefore, if VO2 max intervals come first, and big volume runs should be the focus later, then tempo runs should be placed towards the middle of an ultramarathon training cycle. I recommended that ultrarunners incorporate intervals for only one to two mesocycles (typically mesocycles are around 3-4 weeks each).
How often Should Tempo Running Workouts Be Done?
The frequency of tempo workouts absolutely depends on your fitness level and experience. For newer athletes, I recommend starting off with one tempo workout per week. More experienced athletes can certainly incorporate two tempo workouts per week, and advanced athletes can even attempt to have greater adaptations with back-to-back tempo workouts.
Remember: higher intensity equals shorter adaptation process, but comes at the cost of longer recovery time. When incorporating tempo workouts into your training, you need to put an emphasis on recovery (both rest and nutrition), and monitor your body closely for fatigue.
Ultimately, you do not ever want to incorporate tempo workouts into your training plan in a way that will hinder your overall ultramarathon goals.
Can I do my Tempo Workouts on Trails?
You can absolutely do your tempo workouts on trails (yay, trails!) provided that they are the type of trail – both in vertical gain/loss and technical terrain underfoot – that allows you to continue moving at that tempo effort.
Hills that are too steep will either force you to walk (and likely enter recovery, reestablishing the aerobic respiration pathway) OR will result in you pushing too hard to run up them, entering that VO2 max effort zone, and cutting your interval short.
The same goes for terrain underfoot…if you have to tip toe cautiously to try and avoid falling, you likely won’t be able to reach the lactate threshold effort you are looking for.
But if your local trails allow you to run at that hard, 7-9 out of 10 effort consistently? Then by all means, do your tempo workouts on the trail.
(Roads, tracks, and treadmills are also acceptable)
TEMPO RUN FINAL THOUGHTS:
Listen, I get it. There’s a reason why so many ultrarunners are attracted to ultra distances: we prefer long and slow over fast and hard running efforts.
BUT…when you consider that significant improvements in overall running fitness and performance that can occur when you incorporate tempo running workouts into your training, it makes those “ughh I hate running fast” workouts totally worth it.
When you set a PR at the finish line of your next race, you’ll be glad you took the time to improve your lactate threshold with tempo training.
- McGehee, J. C., Tanner, C. J., & Houmard, J. A. (2005). A comparison of methods for estimating the lactate threshold. Journal of strength and conditioning research, 19(3), 553–558. https://doi.org/10.1519/15444.1
Heather Hart is an ACSM certified Exercise Physiologist, NSCA Certified Strength and Conditioning Specialist (CSCS), UESCA certified Ultrarunning Coach, RRCA certified Running Coach, co-founder of Hart Strength and Endurance Coaching, and creator of this site, Relentless Forward Commotion. She is a mom of two teen boys, and has been running and racing distances of 5K to 100+ miles for over a decade. Heather has been writing and encouraging others to find a love for fitness and movement since 2009.
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