Among the topics we’re asked about most frequently, Zone 2 training is always near the top of the list. The interest is certainly justified; Zone 2 training is one of the four essential “pillars of exercise” for maintaining health and physical capabilities as we age, as it is arguably the single most important tool we have at our disposal for improving and sustaining the health of our mitochondria, which are central players in cellular aging and metabolic health. With this in mind, we’ve decided to create a one-stop resource to answer common questions and serve as a guide for all things Zone 2: what it is, why it’s important, how to incorporate it into an exercise regimen, and more.
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I’m a nordic skier doing double poling, which means I’m a heavy user of those upper body muscles. I can change as many light bulbs as I want to without getting tired 🙂 My capacity for doing zone 2 and staying within resting lactate levels has improved tremendously over the last 10 months. At some point I learned to “feel” the difference between slow-twitch dominated muscle usage in the upper body vs fast-twitch dominated muscle usage – slow twitch is the more gradual building of tension within the muscle whereas fast twitch is more aggressive hitting it hard.
My gain in slow-twitch dominated muscle strength has been absolutely tremendous. I’m really curious as to what the actual adaptations happening here are. It feels like my slow-twitch muscle is growing in size (hypertrophy-like), since my upper body is slowly creeping out of the L size bracket. Surely this cant just be capillary vessels and increased mitochondrial mass ?
At higher levels that zone 2 you are still breathing hard so oxygen is available for the mitochondria. Why would atp generation decrease when the glycolic conversion of substrate does not require oxygen. I have always thought that mitochondrial respiration continues at a high level only limited by the available oxygen.
David kessler
“ However, it’s important to note that regardless of the muscle groups involved in the exercise, the increase in the muscles’ fat oxidation capacity derived from Zone 2 training benefits the body as a whole – for instance by improving glucose tolerance through increased insulin sensitivity.”
While benefits may still accrue generally to the body as a whole, presumably only the engaged muscles improve their fat oxidation capability? (Changing lightbulbs would still lead to burn in the arms and shoulders.) Surely you want to improve fat oxidation capability throughout the entire body?
Stephen: say you were rigorously restricting your engaged muscles to your legs. You are clearing glucose actively via non-insulin-dependent glucose uptake and you will improve the insulin sensitivity of those muscles over a longer period. By allowing you to clear more glucose (and fat), you maintain lower insulin and glucose levels, which is healthy for your entire body.
Also, working muscles release signaling molecules (myokines) which go all over the body and are thought to mediate health benefits, although how important these are is AFAIK still not clear.
Amazing article, I learnt loads! I realised my zone 2 has been a bit low so will try adjusting that and see how I go, thank you.
Thank you for addressing both women and men separately. After reading “Invisible Women”, I highly respect that you distinguish between the two sexes when addressing health issues. Best, Kristi.
I recently had a Mitoswab plus test done (buccal swab) for mitochondrial function. I am a 65 yo female and I have been doing zone 2 for about 18 months now on a Peloton, checking lactate levels as well- approximately 3 times a week- and one day of HIIT (for VO2 max). The physician at the lab who went over the results with me was absolutely amazed at my “almost perfect” mitochondrial functions results. (This shocked me as well since I am often fatigued- though I now suspect this is from my Hashimoto’s/hypothyroidism even though I take thyroid hormone.) He said he has seen almost 5000 test results and rarely has seen results like mine. He did NOT think it was genetics or my healthy diet and/or supplements but when I told him about the zone 2, he was extremely interested in learning more and he believes this form of exercise may explain the results. I am now recommending zone 2 for all of my patients. The problem will be compliance!
I am also a Peloton rider. Can you say more about your routine? Are you doing Power Zone classes or “just riding” with your heart rate monitor?
I was just reading that the Peloton Power Zone level 2 is 60-70% of your max heart rate, so Dr. Attia’s zone 2 would = Peloton zone 3, it seems.
Peloton power zones are bases on output metrics (that number in the middle of the screen bottom). I have been doing power zone rides for 7 years or more and I think power zone endurance rides keep me around the right heart rate zones.
So to summarize, Zone 2 training is staying in your target heart rate for 30-90 min three times a week depending on fitness level?
Is the ramp up to zone 2 baked in to the overall total?
For example, on a elliptical, I’ll set the resistance to 16 and it might take 3-8 minutes to get into my Zone 2 range. I can then usually maintain this for 25 minutes where I either then have to back off the resistance to stay in zone 2.
Conversely, I’ve tried ramping up the resistance and speed to minimize the amount of time it takes to get into zone 2 and then return back to normal to finish out the session.
My question is both Peter and everyone else, is are you ramping up the initial workload to quickly get into “zone 2” and try to maximize the zone 2 duration from there?
Or conversely, is this just baked into your exercise and the time it takes to get into zone 2 is just part of the approach.
My concern with ramping up quickly is a concern for “over-shooting” zone 2 and then hampering the effectiveness of the workout that follows.
Is there an ideal approach?
This is what I wonder more than anything. I’ve heard Peter say he ramps up to Zone 2 over 10-15 minutes. I do this on either a peloton or a treadmill, and after a short warm up (2-3 minutes + dynamic stretching) I’ll go straight to the wattage (bike) or speed/incline (treadmill) and stay there for 60 minutes. I have always been curious how much of those 60 minutes would be considered part of the “Zone 2” workout (I.e when does the actual clock start) as I’m sure my heart rate and internal state are not the exact same in the first 30 seconds as they are 20-30 minutes into the session.
Give it 3:00 to arrive at a ‘steady state’. Don’t blast out of the ‘starting gate.’ First minute, ease in towards Zone 2 goal.
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At the risk of speaking out of school, since I have completed reading the article yet, I still want to make one observation. I immediately scanned the citations and was thrilled to see you cited Phil Maffetone. For me, he is “the father” of the Zone 2 paradigm. If you had written this much on it, and not cited him, I would have had my doubts!
Phil Maffetone’s formula allows for individual differences in training Hx, unlike others.
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The vibe from this article is that zones 3-4 have no value in a longevity training program. But since there are other mitochondrial biogenesis pathways that are activated at higher intensities (ex AMPK), I’m wondering if the variable we really should be optimizing is area under the curve of time vs intensity (total work) per week without getting injured. The average person has time constraints which could make the case for shorter zone 3-4 sessions in lieu of longer zone 2 workouts. Additionally, I find myself obsessively checking my heart rate during workouts to stay in zone 2, which is a buzzkill. Sometimes I just have energy and want to go harder, but hold myself back for the alleged zone 2 optimal mitochondrial signal- another buzzkill. Basically I’m wondering if all the fuss about zone 2 is really worth it for the average person, or would it be better just to focus on maximizing total work? How much less adaptation would one see if they only ever did zone 3 versus someone who only did zone 2?
@j griz A lot of pulse watches have a “zone lock” feature that provides vibration/sound alerts when you exit your pulse zone. Combine this with listening to your breath, when you start breathing heavier you’re out of zone 2. Watch the pulse as your breath returns to normal, the moment your breath stabilizes – that’s your zone 2 pulse. Using these two things you dont need to panic check your pulse. I even do in-the-wild zone2 training by just listening to my breath – it works quite well
This is the exact question i am seeking a solid answer to. I see conflicting answers among different sources. The chart implies that fax oxidation / mitochondria enhancement drops off as the body shifts to burning more glucose. If this is the case, that would indicate exceeding zone 2 reduces the benefits. I also tend to push above zone 2 and remain comfortable steady state for 60-90 minutes without soreness or much fatigue the next day. I’d really like clarity.
The article does clearly indicate that lactate inhibits fatty acid transport and results in reduced mitochondria “training”. A study is referenced for this. I too have been seeking the answer to this same question.
Very useful article. How much time is required to clear lactate after a strength or power workout? Are we talking 20 min? or 20 hrs?
Doing a power workout (e.g. kettlebell swings) won’t be very effective when fatigued. Doing a technique-heavy workout (e.g. barbell squats or deadlifts) could be more dangerous if technique is compromised due to fatigue. If I need to combine strength and zone2 in one workout, and want to do strength first, how can I know when I’ve recovered enough for zone 2 to be effective?
I am a 77 yo male who has been exercising (cardio & areobic) my entire life. I have Afib & I am taking Flecainide(100 mg twice a day). My resting heart rate is 48. Would the fact that I am on Flecainide, lower my zone 2 target range which is 109-119 bpm for someone my age?
I find it hard to believe that slight deviations from “optimal” intensity would make a sufficiently meaningful difference to overall mitochondrial adaptation that would warrant slavish attention to maintaining exact intensity. The two references you use are not at all compelling to me. Is what happens to fat transport in rat heart muscles after 48 hours of chronic exposure to at least 5 mmol of lactate at all transferable to what happens in my leg muscles if i allow lactate to climb by a mmol or two for a few minutes while I run up a hill? Likewise, does the fact that lypolysis decreases by 20 or 30% when blood lactate goes above 5mmol tell me anything about the availability of plasma FFA and IMTGs if i allow lactate to climb by a mmol or two for a few minutes? And does any of this inform me in any way about adaptations to my mitochondria during and after the exercise bout? I think you are doing an unwarranted disservice to people who want to run or ride outside, or who want to do some kind of circuit training to get their zone 2 adaptations. Even if there are slight reductions in mitochondrial adaptation rate, are they sufficient to warrant your protocols? What is the tradeoff? I am not a scientist, but if I am wrong on this I would love for you to go into some depth on why that is, or at least point me to some research that shows me why I am wrong.
For the Peloton riders out there, is there a target FTP that we should shoot for to be in Peter’s zone 2? In this article, Peter said that 75% FTP is too low. I have seen estimates of 85% FTP. I’ve also read others say the Peloton FTP Zone 3 works for them. Any other insights on using FTP as a guide?
Is anyone aware of a continuous lactate monitor? Would save my poor fingers and be enormously helpful to ID zone 2.
Is your zone 2 max HR the HR you maintain during a 45min+ workout at constant power with no drift upward of HR?
In addition to increasing heart rate, albuterol can also lead to elevated lactate levels. I am wondering if this effect is actually noticeable relative to the lactate production from the exercise and whether you can trust lactate levels on albuterol? Are asthmatics such as myself limited to RPE?