The Knowledge is a new podcast from Wahoo. It provides straightforward, science-based, useful information from world-class experts to help endurance athletes maximize their performance. Sports scientists Neal Henderson and Mac Cassin discuss a single training topic in this episode and provide key takeaways to apply to your training.
In this episode, Neal and Mac are discussing low-intensity training and how absolutely important it is in low volume training, and how it's a foundational part of high volume training. What is low-intensity training? And how do we define that? And really, why is it valuable or important? Find out next on this of episode of The Knowledge Podcast by Wahoo!
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Neal 0:00
Hello, and welcome back to another episode of The Knowledge Podcast brought to you by the Wahoo sports science team here in Boulder, Colorado. I am Neal Henderson, head of wahoo sports science.
Mac 0:10
And I'm Matt Cassin senior sport scientist here at Wahoo. Today, we're going to be talking about what you need to know about low-intensity training.
Neal 0:18
Alright, Mac well, I guess a lot of times people think about training volume intensity as purely an inverse relationship. And by that I mean that you know, if you do lots of high volume training, then everything has to be low intensity and vice versa. If you're just doing very low training volume, then everything has to be at high intensity, do you think that really is a true phenomenon? Is it truly A inverse relationship? Or is there may be something else going on?
Mac 0:45
I'm pretty sure I've read that in a cycling magazine once. So I think it has to be true. Do you trust everything you believe though Mack will only stuff on the internet? But on a more serious note? No, I don't believe that is correct. I think that low-intensity training is absolutely important in low volume training, and it's a foundational part of high volume training,
Neal 1:07
I'm gonna have to say, Mack, I do agree with you. And even while I may, kind of trend to seeing the value in lower volume training, overall, for most folks, even very high-end elite athletes, all the way to, you know, your average person just trying to get a little bit better that there is going to be true value in maintaining a certain amount of training that is performed at a relatively low-intensity training, which I think begs the question, what is low-intensity training? And how do we define that? And really, why is it valuable or important?
Mac 1:44
Yeah, so when we're talking about low-intensity training, it's really what most people refer to is endurance or base intensity or zone to intensity, there's a lot of different names for it. But one thing that we found time and time again, is that people are actually riding above that intensity, they're riding too hard when they're doing their quote, unquote, low-intensity days,
Neal 2:02
Definitely, I can tell you having worked with lots of athletes over time, I would say I've probably hundreds of athletes have I reviewed their files of all different types of athletes, cyclists, triathletes, etc. But within that endurance realm, most folks tend to do what should be relatively easy, low-intensity training at a higher than recommended intensity. And so a recommended intensity that I'm talking about is something where we're considering this kind of like a low intensity, General endurance, or aerobic training session. And the easiest, simplest way that I can describe this, if you have absolutely no tools available to you at all to monitor what's going on, you know, excluding lab excluding even, you know, a wearable, any kind of meter is just the simple old school talk test. So, while you are doing the activity at an appropriate low-intensity training level, you should be able to actually have some bit of a conversation with somebody else out loud. But you're not talking about choking through four words between breaths, right? Nope, that's not a conversation. So actually being able to speak several words strung together in the form of a sentence that actually is coherent and makes sense and is participating in the communication with the other person, not just gibberish, words that you quickly say, and then have no idea what you were talking about. That wouldn't count here. We're talking about like, kind of what we're doing right now. Like if we actually started, I don't know, pedaling on on a kicker bike here, we could potentially even do this episode, right? Potentially, potentially correct. And even though we're at a moderate elevation here in Boulder, Colorado, which means we have to breathe a little bit more air in and out every minute than we would at sea level, we could still have a conversation pace type of effort, while exercising at an appropriately low-intensity effort.
Mac 4:06
So you want to break down what this looks like in a lab setting first?
Neal 4:10
Yeah, so definitely do have a background of doing lots of testing in the lab. And there are a few different things that we can use. And I'll talk first about blood lactate. So we do blood lactate testing to assess the amount of lactate that is present in venous blood, during activity, or even at rest. But that net blood lactate is is a balance of what is being produced and what is being cleared out. And so when somebody starts at a very low intensity, they're going to have you know, a relatively low amount of blood lactate because lactate is being produced when there is carbohydrate being broken down without utilizing oxygen is where we have a higher amount of lactate that will be produced.
Mac 4:56
And I think that's a good time to bring up the fact that lactate has a lot Has a bad reputation in the insurance world, but it is actually a fuel source.
Neal 5:04
Absolutely. Your heart muscle, some of that tissue only can use lactate as a fuel cell type. That's pretty cool in terms of those cardiac myocytes, and what they're capable of doing, only using lactate. But the body even at rest, like if you were sleeping, which I would never do this to a person, if I went and like, did a little blood lactate stick and measured blood lactate, we would probably still see even sleeping one, one and a half, two millimoles of lactate at complete, utter rest. Typically, you know, one of the tests that that has been used in the lab is a lactate threshold test or lactate profile test, which starts off nice and easy. And every few minutes, typically three or four minutes to get a steady-state, we do another blood lactate stick. And we see and in some cases, that second third fourth stages that the lactate levels are lower than they were initially before we start to see them turn up, it's where these lactate levels are either stable or either slightly decreasing as what we would consider that steady-state aerobic endurance level of training. In most cases that are less than two millimoles as absolute millimoles of lactate per liter. And some folks we see even those baseline lactate levels drop even less than one millimole per liter, which is a pretty low lactate concentration.
Mac 6:22
So then another way that we can sort of monitor this in the lab is if we hook you up to a face mask and measure your expired gases, your expired oh two and expired co2, we can look at those ratios. And what we can see is there's generally for most people around that low intensity, they'll be using about 50%, fat, 50% carbohydrate, and up depending on muscle fiber type, if you're more of a sprinter type person or real diesel engine, you know, sprinters are going to be less aerobic Li efficient, they're going to use more carbohydrates at that low intensity, more aerobic diesel, people are going to use more fat at that same relative intensity. And there's one, one method to identify the more optimal range for this sort of endurance training is looking at fat Max, which is where you're actually using the greatest amount of fat, that might not necessarily be the greatest percentage of fat, because as you increase the intensity, you might use a bit more carbohydrate, but the overall energy expenditure is higher, so you can be burning more fat. And one of you know, big drivers of aerobic adaptation is basically forcing your mitochondria to work oxidative Lee. And the best way to do that is to force them to use as much fat as they possibly can. Definitely, there's the doc test. And then there's the will not talking test because you're hooked up to a gas mask, but to two different spectrums that can get you to the same thing. So when you keep that in mind, when you think about what type of rider you are, because if you're more sprinter, you might need to be on the lower end of the classic endurance ranges. And if you're more aerobic, you might need to be a bit towards the higher end. So not everyone's going to be exactly at, say 75% of FTP for an endurance ride, some people need to be lower, and some people can be at that upper limit.
Neal 8:03
Definitely. And I would say as a general rule, we've seen, you know, somewhere around 50 to 75%, of FTP being that that kind of target range for these general endurance aerobic training rides. If you don't have any additional specific testing information to help give you that guidance of you it might be 50 to 60% is really in that sweet spot for someone else it might be 70 75% is where that kind of optimal ranges. And so if you don't have access to identify and those kinds of things, well, you have a little bit of a bigger range to work with, but you can then cross-check it with that talk test, as well as then there are some new tools out there that we're starting to use specifically looking at one of the kinds of calculations that's possible from HRV analysis, which again, HRV stands for heart rate variability in this is the difference in time between successive beats. And there is some variation that we see whether at rest and during exercise. And there are some different shifts in some of these calculated values, one of them being known as DFA alpha one, yes, we could kind of go into the specifics of detrended function analysis alpha one and go through a bunch of algorithmic definitions of what that is, but honestly, big picture, there's some evidence to suggest that when this value goes below 0.75, that you have shifted from a kind of that true aerobic range into what we typically call the tempo range, which if we look again, from a lab perspective, we would see a shift and an increase in the percentage of carbohydrate being utilized at that intensity. We would also see a slight increase in blood lactate concentration, maybe an increase in 0.5, or one millimole yourself. Still not beyond that breakpoint where you're producing more lactate than can be cleared, it can be sustained for quite some time for many hours, in fact, but there becomes a little bit of a cost in terms of kind of your increased sympathetic nervous system activation, and specifically, then some of the resultant increases in the release of stress hormones, which will then potentially slow down your body's adaptation to that training session, if you do simply too much of it.
Mac 10:31
And I think that's something that a lot of people get wrong, when they're doing lower volume training, they might think I've got two hours, and I'm supposed to do an endurance ride. So I'm just gonna actually just do a tempo ride for those two hours. And generally, if you're doing lower intensity, lower volume, overall, a lot of your days are pretty hard. And so you're robbing yourself of the benefits of a real endurance session and you're taking away you're putting more stress on your body. So you're not going to be able to perform as well, on those high-intensity days, building off that, you know, another portion of low-intensity training is, you know, what we call active recovery sessions. And that one is, in particular, I know, one of the first things that you told me when I started working with you is, you should be embarrassed to be seen out on your recovery rides. And for all my time coaching, the only time I've ever gotten angry or upset with anyone I've been working with, it's when they mess up their recovery days and ride too hard.
Neal 11:25
Exactly. So the act of recovery is really just about trying to accelerate the recovery process by moving a little bit, it's not trying to add stress to the system, it's trying to accelerate your body's capacity to adapt to the stress you've already placed on it. And so if you push too hard on those days, you are working against yourself. And that just makes me sad as a coach, that makes athletes less fast. So you know, again, that's another thing that makes me sad, too. So thinking about those active recovery days, I have athletes that, you know, I've tried, like, I'm trying to average less than 100 watts, even though, you know, I had an athlete that tried to do that whose FTP was almost 400 watts. And it was a game for him to see how low he could go truly with that power output on the day as well as heart rate, if he could not go over 100 beats per minute, on an active recovery session, then it was successful.
Mac 12:22
Some people think that it seems so easy that there's no point in doing it. But again, it really does accelerate that recovery process. A big part of that's just you know, getting adequate blood flow to those muscles that you are normally training if you don't do anything for the day, you know, you don't get those the dilation of the blood vessels in your legs, and you don't get nutrients don't go as efficiently down there to refuel and replenish you. So they're definitely very valuable sessions. Even if they don't feel like it. Everyone likes to think they're not going hard, I'm not getting faster. And that's definitely not true.
Neal 12:56
Yep, the value of clearing out inflammation and getting carbohydrates back into those areas that may be depleted, as well as getting protein there to rebuild, when we are doing kind of stuff that's really stressful on the muscles, that's what's going to make you faster more quickly. And also, there's some interesting evidence from an end criminal illogical point of view, in that you're going to see a near-equal increase in growth hormone response from that very low-intensity session as you would from a higher intensity session, and you're not going to get any of the catabolic effects that do tend to come in line if we start moving into the higher intensity realm. And especially if we stay sustained even that moderate intensity, like tempo realm for a long period of time, we get significant catabolic stress there. So recovery is part of the name of the game as well as managing the intensity on your general endurance days.
Mac 13:53
So for endurance intensity, now, what's your recommended heart rate range?
Neal 13:59
Yeah, it's, it's, it's gonna be for sure, some variation, but often we're talking about 20 to 40 beats below what we would consider like a threshold heart rate, which again, is probably closer to between 85 and 90% of Max heart rate for most folks, where that true kind of breakpoint, the higher intensity threshold is. So still, you know, not terribly intense. The one caveat that I would throw in some cases, if we do look at heart rate, we might down-regulate our intensity in certain circumstances like high altitude or extreme heat, so that we're not over-stressing our body in our system. So if I was doing you know, some specific heat tolerance work after some specific intensity, I might just clamp the heart rate to a certain level and just let the peak power be what it is, and it's probably a lot lower even Then the suggested recommended kind of levels that we might see from what would have been a lab test done in a standard environment or just our general fitness level. So might even be just 30% of FTP, if we're in a pretty extreme heat environment, or you like, say, go to Leadville, and you go and do some rides up at, you know, over 3000 meters or over 10,000 feet, you're gonna have to down-regulate that typical target power, and listen to your body and look at the physiology and pay attention to that. And let's just say, you know, if my threshold heart rate is 156 beats per minute, then my, my aerobic range is probably more in the 120 to 130. And though maybe at sea level, or say at Boulder, I'm pushing, you know, 150 or 180 watts up at Leadville, maybe only 110 120 130 watts, and just paying attention to the heart rate rather than try to over override it and hit a target.
Mac 15:56
Yeah, and that's and that's something we've touched on in another episode, you know, using multiple, you know, your heart rate, your power, using all those things, really dial in your sessions. But it's important to remember again, like with power with heart rate, these are ranges and you don't need to be at the top, I know my first few years training, I would always for my zone two days, I'd go out and I'd make sure that either I'd be at the max for power until my heart rate crept up, and then I just keep it pegged at heart rate, and then my power would slowly slowly slowly drift down. And yeah, in retrospect, I could have gotten a lot more out of a lot of those long days if I'd been a bit smarter dial back and was just in that zone without trying to pin it at the absolute upper end of that, though.
Neal 16:39
Yeah, definitely. I would say it's usually better to shoot for the middle at the start and then see how the day is going and how your body's responding and be able to make those little tweaks up or down. You know, some folks like though we start lower and then rev it up a little bit. That's definitely better than starting at the top end and fading out. All right, well, with that, I hope you have a better understanding of why your low-intensity level training might be so low and may feel like it's too low, but you now should understand that it's appropriately low and easy and you can manage your training to get better, get faster and have some fun while doing it. We'll catch you next time on the knowledge podcast.