Happy Monday! Not much to report here, which is always a good sign :). We’ve been slowly checking off various overdue projects, but they have largely felt manageable this past week!
Recently, ‘chatter’ about different heart rate zones has been floating around in running media in response to both Kilian’s and Kipchoge’s world class performances this past month. What has been especially noteworthy is the time that both athletes spent in ‘zone 1’ during their training blocks (upwards of 70% for each athlete depending on the reliability of the HR monitor and also speculating regarding Kipchoge as there isn’t a lot of recorded data),
A few of you have asked specifically about ‘Zone 1’ and others have had some other more generalized questions regarding running zones and what they ‘really mean’. So… I thought this would be a great topic for today (and next week, as it’s a lengthy topic)!
One especially confusing aspect about discussing different heart rate zones is whether or not you’re basing off of a 3 zone or 5 zone model. Training Peaks will even confuse this further with different sub-categories that go beyond the scope of this newsletter as well as beyond the scope of what we should really ever worry about (if Kipchoge can run just over 2:01 without tracking specific metrics in training… we don’t have to worry about 10 different zones to quantify the training that we’re doing).
A 3 zone model is split into easy/mod/hard. Easy (zone 1) is anything below aerobic threshold (AeT). Mod (zone 2) is anything below Lactate Threshold (LT) but above AeT. Hard (zone 3) is anything above LT. I want to use this model to explain why we care to discern between easy/mod/hard intensity. AeT is also considered the metabolic ‘crossover point’; where we go from primarily utilizing stored fat for energy production to primarily utilizing carbohydrate (either stored in glycogen or exogenously consumed). From my understanding, the energy you can readily access from exogenous fat during exercise is rather limited (I can’t remember the specifics off the top of my head and the scope of this). You may also run into the terms Ventilatory Threshold 1 and 2 (VT1 and VT2). As far as we’re concerned VT1 is AeT and VT2 is LT.
Easy/mod/hard changes the sustainability of exercise. As we prefer carbohydrates as substrate (which we’re still using during easy running, just to a lesser extent), we accumulate more metabolic byproducts. One of these byproducts, lactic acid (LA), can be measured and as it increases the intensity becomes less sustainable. At AeT, you start to note an increase in LA produced and at LT you notice an increased rate of LA produced (going from largely linear to exponential increase). If you’re confused, I totally get it! This is largely scratching the surface, but Alex Hutchinson has some interesting articles that likely do a better job of describing the above and doing so in an easier to understand way.
Now…let’s dive into a 5 zone model. Zones 1 and 2 in a 5 zone model are ‘easy’ in the three zone model. Getting a hard set rule to distinguish between the two outside of a certain percentage of LT HR or max HR is surprisingly hard to find. Kilian describes the output as what he could run while breathing only through his nose (I wouldn’t suggest just breathing out of your nose). It’s the difference between ‘easy’ and ‘really easy’.
What is somewhat confusing is how David and Megan have recently discussed zone 1. First, just know they are describing it in the context of the 5 zone model (they switch back and forth on occasion). Second, they talk about how much time Kilian and Kipchoge spent in zone 1 and then mention that ‘volume limited athletes’ shouldn’t spend as much time in that zone. These two elites can run objectively fast while staying in zone 1. This allows them to stay biomechanically efficient without taxing their metabolic systems too much. Additionally, they may be training 15hrs/week and if most of that time wasn’t in zone 1, they’d just be beating up the legs too much to be sustainable (I think I heard <6min/mile pace is likely zone 1 for Kipchoge, which makes sense based off of his marathon time…running 10hrs/week at <6min/mile pace is just too hard on the body).
For most of us…we’re not dealing with that speed! So, spending more time in zone 2 to develop efficient biomechanics is advantageous. We can still spend time really going easy, but doing 70% of our training in zone 1 would lead to frustratingly slow progress, and possibly none at all if on a timescale where aging doesn’t catch us first.
Next week, we’ll dive more into the 5 zone model. We’ll discuss where the different zones line up in terms of racing distances, but I feel like this is a good approach to lay out the outline and answer any confusion regarding zone 1 vs. zone 2 in the context of other articles and podcasts recently published.
Doing these from the week before is working well, so I’m going to keep with that!
James M. ran his first 50k at the inaugural Mammoth Trail Fest 50k! I always joke that nobody regrets starting off an ultra going ‘too slowly’, but after closing out the day hard and seeing some time that could have been shaved off, James informed me that he wished he went out a little faster :)! I think he caught the trail/ultra bug and I’m pretty confident there are going to be some badass races and performances ahead!
Lukas S. ran a strong race at the Team Alpin Trail 50k! After a rough start to the day, Lukas closed really strong, passing many people on the final climbs and descents to snag a top 10 overall! Additionally, Lukas did all this while navigating the waters of being a new dad…to twins!
Ben L. finished 4th at a local 22 miler! I’m pretty sure I write this 9 times out of 10 when Ben races, but he is so incredibly busy and essentially pulls these things off…off the couch! I used to be surprised when he’d have such strong performances, but he’s rather consistent on race day and can tough it out to get the finish!
Austin C. and his team won their soccer tournament! I certainly had nothing to do with this…and soccer scares me as there are lots of people kicking you and plenty of opportunities to blow out and ankle or a knee, but it’s still pretty darn cool to snag the win!