zone 2 hype

Why Zone 2 Hype is Bad For You

Easy is in. If you are an athlete and paying even a little attention to endurance sport media, you have likely been inundated with content hyping easy training intensities. ‘Go slow to go fast’ is trending, with loads of content creators going all in on Zone 1, Zone 2, more rest days, fewer intervals, and avoiding Zone 3 at all costs. They’re not wrong but they’re encouraging the overuse of a blunt instrument where a nuanced approach is more appropriate. Zone 2 is good for you, but here’s why overhyping Zone 2 isn’t.

The Strength of Simple

I’m not above the fray when it comes to commercializing training content. I’ve made a career of packaging training and nutrition ideas in ways that resonate with athletes. I co-authored “The Time-Crunched Cyclist”, which promoted the idea of using high-intensity interval work to address athletes’ common pain point: limited time available for training. The boundary, for me and for the coaches I’ve worked with, is saying that any method of training is the only one that works.

Human physiology and the factors that influence human performance are incredibly complex. The interventions that improve physiology and performance can be remarkably simple. More importantly, because of the complexity of the body and mind, multiple interventions can lead to similar adaptations and improvements in real-world performance.

Anyone trying to sell you a training method, workout product, diet, or supplement by excluding and dismissing everything else is more interested in commerce than performance.

Why the hype around Zone 2?

Zone 2 and an emphasis on easy to moderate intensities for aerobic development are easy to hype because they work. A high volume of easy aerobic training has always worked.

Zone 2 is a low intensity training zone that is almost entirely powered by aerobic metabolism. This means most of the energy expended while riding in Zone 2 comes from the breakdown of fat. It also means the contribution from carbohydrate is low, and there is very little energy coming from anaerobic glycolysis. Because you have essentially unlimited fat stores and only limited carbohydrate stores, this intensity is sustainable for very long periods of time.

If you have the available time for it, a large volume (10-20 hours per week) of predominantly Zone 1 and Zone 2 training will:

  • Increase mitochondrial density: accelerates the rate at which you can break down fat and carbohydrate to usable energy within muscle cells.
  • Increase capillary density: improves blood flow to and from working muscle cells.
  • Increased fat oxidation at greater power outputs (i.e. you rely on fat for fuel a bit more, which spares carbohydrate for more intense efforts).
  • Read more about the benefits of Zone 2 training

The adaptations from low to moderate-intensity aerobic training are phenomenal. They create the foundation necessary to support higher intensity workouts as well as the high power, high speed efforts that win races.

Zone 2 is also easy for coaches to explain and prescribe; you just go ride at a conversational pace. It’s more appealing to a lot of athletes than hard intervals, and it’s simple for athletes to execute. However, that doesn’t mean athletes are good at completing hours of easy training. Many athletes overshoot Zone 2, which is the problem or mistake the current Zone 2 hype capitalizes on.

What Zone 2 Hype Overlooks

Helping athletes recognize they’re likely riding too hard during long aerobic endurance rides is a good thing. However, the benefits of ‘train slow to race fast’ are being oversold and overhyped. This is particularly true for amateur cyclists with limited training time.

Time x Intensity = Workload

Your training workload must create enough training stress – during individual workouts and across weeks and months – to stimulate adaptation. Moderately trained amateur cyclists often run out of available hours before accumulating sufficient workload to continue making progress. Adding intensity provides the opportunity to create the necessary stimulus.

Proponents of low-intensity training often suggest the benefit comes from reducing training stress rather than seeking to increase it. And for athletes who have been overshooting Zone 2 during endurance rides and maintaining a high level of training and lifestyle stress for a long time, they’re right. Buying into the Zone 2 hype for a few months or a whole season can create a period of deloading. This may rebalance stress and recovery, give the body the opportunity to reap benefits from long-term training, and help athletes recover mentally from highly-regimented training plans.

There’s more to training than sports science

The current Zone 2 hype overlooks many of the non-sports science components of performance. All athletes have affinities for certain aspects of training and are willing to endure the aspects they don’t enjoy much. If you love long easy rides, the hype around Zone 2 probably resonates very well! For athletes who enjoy structured or spontaneous hard efforts, it may be difficult to maintain interest in long periods of easy training. If you were a pro you’d do whatever was necessary, but to stay engaged as an amateur it is important to incorporate training you like to do that is also effective.

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Training must address all your goals, even if that means aspects of your training aren’t optimal for sports science. The degree to which you utilize training for social connection, stress relief, an anchor for daily routines, transportation, and – of course – fun, affects the composition of your actvities and the distribution of your exercise intensities.

What works for pros doesn’t always work for you

Polarized training, which features a large amount of easy to moderate intensity training (80-90% below Zone 3) and a small amount (10-20%)of highly focused interval work at Zone 4 and above, is another training paradigm that can work very well for cyclists. The proof of concept came from ranks of elite endurance athletes. That’s what the annual training intensity distribution looks like for many of the world’s best cyclists, runners, triathletes, and cross-country skiers. That doesn’t necessarily mean it’s the best intensity distribution for you.

Here’s why. Gradually increasing training volume was another important factor in athletes’ progression from amateur to elite. Training became more polarized as their progression continued. In context, this makes sense. As you increase training time, overall intensity must decrease to control the rate at which total workload increases. Athletes don’t have infinite energy nor infinite time for recovery. So, if you’re going to increase annual training volume and incorporate the intensity required to meet sport-specific demands for elite competition, the vast majority of that volume needs to be easy and moderate.

For Time-Crunched Cyclists, the more applicable lesson from the pros is to be deliberate with intensity. Whether the distribution works out to 80/20 or 70/30, the more important aspect is to separate hard from easy.

What Amateur Cyclists Should Do

A big part of the reason Zone 2 got so hyped is that lots of cyclists gravitate to Zone 3 – a moderately challenging aerobic intensity – and end up spending too much time there. But if you’re being purposeful about it, Zone 3 can be used effectively to increase training workload and stress on the aerobic system. And if your goals require high-power and high-speed efforts, you eventually need to incorporate similar efforts in training!

If you’ve been diligently (or unwittingly) following a predominantly Zone 2 training paradigm, consider the following as potential next steps:

  • Separate Zones 2 and 3:

    In TrainingPeaks or your preferred training software, look at the power and/or heart rate zone distribution of your individual workouts and weekly training. You may find you’re spending the same or more time in Zone 3 compared to Zone 2. If so, work on creating greater separation between Zone 2 and Zone 3. You’re most likely just going too hard on endurance rides rather than executing endurance rides in Zone 2 and performing intervals (Tempo and Sweetspot) in Zone 3.

  • Examine your performance goals for the season:

    If your distribution is almost all Zone 1 and 2, consider your goals for the season. A base of aerobic endurance (from that Zone 1 and 2) is the springboard for performance at higher intensities. But, power for high-intensity efforts doesn’t appear through magic. You still need to do the high intensity training. When you incorporate intensity, keep it to one or maybe two interval workouts per week. Advanced athletes may be able to add a third. Don’t tip the scales too far in the intensity direction you’ll ramp up workload too quickly and eventually erode your aerobic foundation.

Once you layer higher intensity atop the aerobic base from Zone 2 work, you’ll have a well-balanced engine for speed and endurance. Focusing too much on Zone 2, to the exclusion of other areas on the intensity spectrum, will make you a wonderfully economical cyclist who can ride all day. However, it won’t provide the physiological flexibility for high-speed, high-power efforts during group rides, races, and personal challenges. To be a complete cyclist, your training needs to incorporate efforts from the full spectrum of intensities.

By Jim Rutberg,
CTS Pro Coach, co-author of “Ride Inside“, “The Time-Crunched Cyclist”, and “Training Essentials for Ultrarunning

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Comments 16

  1. Zone 2 is BS for the common person. The second your heart rate goes out of zone 2. That’s it. Your done. You’re not getting back in. I’m interested in learning more about REHIT.

  2. Pingback: How to Be a Better Cyclist in 6 Weeks - Chris Carmichael

  3. I have also leaned towards the zone 1/2 in the start of the season, or pre season if you like. I know from beeing a interval dude before, that there are very few interval days needed to get me up to speed in the end. But for me the zone 2 period is gonna bring me to that interval period more ready and more fresh than ever. I am mostly inspired by Niels Van Der Poel , the soeed skater. He who wrote “How to skate a ten K” and put it put on the internet for free. He uses enormous blocks of zone 1/2 as the solid vase for enormous blocks of intervals later on his way to the competitions

  4. For those of us who are older or getting older, see “Fast After 50” where Joe Friel reviews the data concerning “long and slow” (e.g. long power zone 2) versus the need for high intensity workouts in order to slow the performance declines that come with ageing.

  5. There seems to be a bunch of different information floating around about what constitutes Zone 2 with some saying that Zone 2 training relates to staying just below your lactate threshold Vs riding at zone 2 hr or power. Zone 2 hr or power can be not enough work to realize benefits of the zone 2 concept from what I’ve read.
    In a perfect world they would be the same but for me personally the difference between and easy conversational pace and zone 2 power is noticeable. I can typically ride well into zone 3 power and carry on a non stressed conversation.
    Any thoughts on that before I go pay a bunch of money for lactate threshold testing? Or am I misunderstanding where zone 2 is supposed to be? From a hr perspective I am somewhat of a freak with a resting of 58 and a threshold of 175 and a max of 192 (I am 53 and these numbers have been consistent for many years). So even hr zone 2 for me ends at 153 beats (which seems pretty high).


      1. Jeff- Unless I’m misreading something here. By now you must know there is so much advantage to conducting a Functional Threshold Test using a power meter? You don’t need to pay anyone. Got a power meter? You can conduct an FTP. It’s really the best way to create, specific for you, the 7 training zones. That power average number you produce at the end of the test will be used to simply calculate percentages of that number to represent your training zones. Ex: Zone 2 (Endurance) is .56-.75 of that number. Using Heart rate only, although important is limited because HR just can’t respond quickly enough to the efforts as it lags behind any increases or decreases in efforts as you go about your training. Most definitely do a Functional Threshold Test.

    1. I’m 64, generally ride 120-160 miles a week and in the same situation. Max heart rate was 178. Resting, mid 50’s.

    2. The only way to know is get the threshold testing. I’ve been doing a ton of research on this and yes, I’m a woman different from you, but no matter; zone 2 is zone 2 If you can afford the testing or you’re an athlete and someone else is paying for it, I said do it to find that threshold and know when you’re in and out of zone two. But like I stated in my own message, it’s bullshit for the common person because once your heart rate goes out of zone 2 your body switches to different metabolic system and you’re not going back to zone 2 until your next work out. It’s very hard to know when you’re in an out of zone to Dr. Attia has talked about this a ton of researchers have talked about this but ultimately zone two is really tough for the common person who doesn’t have access to all those resources..

      Many of us don’t have the time because you need at least 45 minutes to do zone 2 work out to get the benefits optimum is about an hour and a half most of us don’t have the time to do that for five days a week. I am looking into REHIT.

      1. I’ve heard this same information from Dr. Atieh. Can somebody please cite the research study. I’m tired of hearing a bunch of opinions without actually having references to research papers.

  6. First you burn glycogen stores, then fat on a long zone 2 ride. My biggest question how many zones are you talking about? I’ve had people talk about 4, some 6, my Garmin has 5.

    1. Hi Linda normally is 5 zone heart and 7 zone on power, but zone 1-2-3-4 are the same
      Z1 recovery
      Z2 endurance
      Z3 tempo
      Z4 ftp
      Enjoy your bike 😉

    2. From what I’ve listened to from Inigo San-Milan:
      In Zone 2 you are utilizing mostly Fatty Acids for fuel, not glycogen. You are burning some, but at a slow enough rate that you can maintain your lactate level below a certain level (2 millimoles?).
      Once you cross out of Zone 2, lactate starts to build up, which blocks the metabolizing of fatty acids. You have to clear that lactate before returning to true Zone 2, which after hard intervals could take up to 30 minutes. Because of this, he recommends that if you are going to do intervals, do them near the end of the ride so that your zone 2 work is clean.
      Zone 2 improves mitochondrial function, which is where both fat and lactate is metabolized. Better mitochondrial function means you can ride harder before transitioning to relying primarily on glucose for energy, and when you do go harder you can return to burning fat more quickly because you process the lactate more efficiently.
      Dylan Johnson has talked about science that contradicts this article’s assertion that you need a lot of volume at Zone 2 for it to be beneficial, and that even for time crunched cyclists maintaining an 80/20 ratio of zone 2 to high intensity is recommended.
      Personally, I’m focusing much more of my time at Zone 2 because I don’t race and my primary concern is controlling by T2 Diabetes. I’m starting to mix in some higher intensity intervals on days I feel good near the end of my ride, but only just and nothing structured.
      Note: I’m neither a trainer nor a biologist. I’m repeating what I’ve heard recently from Dr. San Milan and from Johnson whose videos tend to cover scientific studies regarding athletes.

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