Lactate's three flavors: tolerance, clearance, and shuttling
Lactate tolerance, lactate clearance, and lactate shuttling. Let's talk about the differences...
WEEKLY WISDOM: LACTATE’S FLAVORS
First of all, let’s talk about what lactate is because that word gets thrown around a LOT in the running space. However, I’m not going to bother because I couldn’t tell you much myself, being that I’m still a newbie when it comes to the nerdy metabolic science stuff. So, here’s what Iñigo San Millán, PhD, had to say here:
We know now that lactate formation can occur under aerobic conditions, and that lactate production is the result of glucose utilization by muscle cells under aerobic conditions. From Brooks’ work we also know that lactate is not a waste product. In fact, it is the most important gluconeogenic precursor (new glucose generator) in the body. About 30 percent of all glucose we use during exercise is derived from lactate “recycling” to glucose.
Now, I don’t know what a “gluconeogenic precursor” is nor do I care to know, but what we should all takeaway from Iñigo is that lactate is an essential source of energy.
LACTATE TOLERANCE
OVERVIEW
Lactate tolerance is about how well your body can handle high levels of lactic acid. Developing this ability in training will allow you to COPE with the effects of acidosis, or that dreaded burning sensation that can often lead to a gritty and slow race finish... As the race distance gets shorter and acidity levels rise, this quality becomes more and more important. As such, this can NOT be overlooked for those racing the mile down to the 800-meter where your body gets flooded with lactic acid. However, it’s still important to emphasize for races as long as the 8k where towards the end you’re going to enter that state of acidosis (as long as you’re racing hard). Notably, this work requires significant recovery periods, so don’t expect to do one of these workouts and bounce back for another good workout in two day’s time.
HOW TO DEVELOP THIS
This quality cannot be improved by traditional lactate threshold work where lactate levels in the blood are at lower stabilized levels. Rather, you must expose yourself to high levels of acidity primarily through work at 800-meter to mile pace with fairly short rest (1:1 work-rest ratio), albeit intervals at 3k pace off shorter rest (1:1/2 work-rest ratio) will also work.
EXAMPLE WORKOUTS
2-3x(3x600m at 3k pace w/ halved rest) w/ 3-4’ rest between sets
8-10x400m at 1500m pace w/ equal rest
2-3x(3x300m at 800m pace w/ equal rest) w/ 4-5’ rest between sets
LACTATE THRESHOLD
Lactate threshold is different from lactate tolerance in that it’s about DELAYING the onset of acidosis rather than COPING with it. Thus, they cannot be put in the same category; improving one does not improve the other. This quality is critical for success in the 10k to marathon distances, but should be developed even in the 800. After all, the better your lactate threshold, the longer you can run at race pace without reaching heightened levels of acidosis and the consequent slow-down.
LACTATE CLEARANCE
One form of lactate threshold is lactate clearance, defined as your bodies ability to CLEAR or ELIMINATE lactate (and its nasty byproducts) to prevent you from entering a state of high acidosis. With an adequate level of lactate clearance for the given athlete and event, they will be able to make it farther in a race before regressing. This is a crucial quality for giving yourself a chance to beat your competitors at the end of a race.
HOW TO DEVELOP THIS
There are many ways to improve this ability. Threshold cruise intervals of 400m to 2k in length at slightly above anaerobic threshold with short rest are great for developing this, but short intervals at 5k-10k pace with very short recovery, fartleks, steady thresholds, and flux-style sessions can also be used. Basically, there are a lot of ways to develop this quality!
EXAMPLE WORKOUTS
Mile repeats: 5x1-mile at 0-5” above threshold w/ 1’ rest
Fartlek: 8x(3’ at 5-10” above threshold, 1’ easy)
Flux 400s: 4x(4x400 at 5k pace w/ 100 jog) w/ 400 jog between sets
Steady: 20-30’ at 0-5” below threshold
LACTATE SHUTTLING
Lactate shuttling is about how well your body can TRANSPORT and USE lactate as an energy source. Yes, that’s right, your body uses lactate as fuel! It’s actually the nasty byproducts that come with rising lactate levels that hurt performance (e.g., the positive Hydrogen ions). In a way, shuttling is a mechanism of clearance; the more cells you can shuttle lactate to, the more lactate can be used and then cleared. Thus, the better your body can transport this fuel source to the muscles and use it, the better off you will be come race day. This quality is especially important for races with hilly terrain or a high number of surges—random speed bursts often seen in races with high caliber athletes—where your lactate levels will ebb and flow throughout. Without this quality, you might be capped out at your race pace and not be able to adequately handle lactate spikes that come from mid-race surges, hills, etc., leaving you behind the competition.
HOW TO DEVELOP THIS
Flux training, alternations, in and outs, lactate dynamics, or whatever you want to call it are best for developing this as they expose your body to a rollercoaster of lactate injection in which you build up your lactate levels on the faster portions and then run at a steadier (not slow) pace to bring those lactate levels back down before the next rep.1 Thus, over the course of the session, your overall lactate levels may (and likely will) rise, but throughout you’re giving your body opportunities to recover and get back into a readied state. Notably, you can also use steadier threshold runs with rolling terrain or a steady threshold with surges to build this quality. These workouts are a lot tougher than you might think, but working these into your training will be of great benefit to you.
EXAMPLE WORKOUTS
Flux 400s: 3-4x(400 at 3k pace w/ 100 jog) w/ 2-3’ rest between sets
Alternations: 4-6x(800 at 10k pace, 800 at marathon pace)
Steady threshold: 24’ on flat terrain at threshold w/ 30-60” surges at mile-5k pace every 4 minutes
WRAPPING IT UP
To recap, lactate tolerance is NOT the same as lactate threshold. Unlike lactate tolerance where the focus is on COPING with acidosis, lactate threshold is about DELAYING the onset of such. The latter quality has two main sub-categories: clearance and shuttling. You should not neglect either of these qualities as they are very complimentary to each other. If you’re just smashing long sustained tempos (i.e., lactate clearance), you’re not going to be good at handling spikes in lactate. You’ll just be a great time trialer, but a poor competitor. On the other hand, if you never touch those clearance-focused sessions, you may find yourself unable to make it to the final stages of a race with your competitors, despite being able to handle the occasional spikes in lactate from the early and middle stages.
If you have further questions, please ask me of course! See my contact information at the bottom of this post; I would love to help. You can also read this link for more information on this topic from Jon Marcus.
Next up on All Things Running… Klass Loks’ Easy Interval Method: A unique interval-based training system.
SUPPORT ME
Follow me on my other media through this link.
If you want personalized coaching and/or training advice, I’d be happy to help. You can email me at jacobreesmontgomery@gmail.com or send me a direct message on Instagram.
I have a post on flux workouts that you can read if you’d like to learn more!