I’ve always been fascinated by the training process. Exercise applied in the quest of a specific outcome. The stimulus-adaptation response in humans. This certainly explains my career choice.
My interest in the relationship between performance and longevity continues to grow. How can we best improve fitness and athleticism at any age, and what are the ideal ways to keep those properties present throughout the lifespan?
Maximal oxygen uptake, or VO2max, represents the upper limit of oxygen you can process during exercise and it is expressed in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). Regarding performance, this is known as aerobic power or capacity. In terms of longevity, it is a definitive marker of functional independence.
A very popular topic in current media is VO2max training for older athletes. All the usual questions come into consideration. Who? What? When? Where? How? Why? “How much is enough versus too much and are there specific risks associated with this type of training?” I’m going to attempt to expound a bit on each of these and a few other questions.
Who should be doing VO2max training? As with many areas in health and fitness, there is often disagreement about who needs to perform this type of exercise. It would be reasonable to think that this type of training is best reserved for young to middle aged endurance athletes. But that would be incorrect. It is my opinion that anyone concerned with lifetime fitness and performance, given adequate medical clearance, should be doing VO2max training on an occasional to regular basis. The reason I’m somewhat generic in that recommendation is because what really matters is that you have “good” VO2max. How you achieve that level can be quite variable. Due to genetics and training history, some people need more or less than others in order to achieve the desired result. However, in general terms, everybody benefits from some amount of this type of exercise.
What exactly is VO2max training? First of all, many forms of exercise can have a beneficial effect on VO2max. This includes low intensity, steady-state aerobic training, circuit workouts, and sports participation, among others. But the greatest stimulus to increase your maximum oxygen uptake is widely recognized as moderate to high intensity interval training.
Any session which includes several high-effort bouts paired with rest intervals can and will have a stimulating effect. That stated, the literature identifies a certain type of HIIT as VO2max interval training. Broadly, that’s something along these lines: 3-6 reps of 3-8 minutes at somewhere between 85-95% of your maximum heart rate, with active rest intervals of approximately the same duration as the rep. This can be performed in a variety of modes, such as uphill hiking, cycling, running, swimming, rowing, cross-country skiing, etc.
When should a Lifetime Athlete perform VO2max training? I’ll answer this in two ways: frequency (number of sessions per week) and time of day. Unless you are a competitive endurance athlete (I’m going to address this case in greater detail a bit later) in a specific buildup or peaking phase, once a week (or even once every 10-14 days) is fine. A properly formulated and executed weekly VO2max workout, built into a comprehensive fitness for life program, is more than adequate to develop and maintain VO2max. As long as those other elements, which we drill down upon so often here, are present.
I have a bias regarding time of day. You should do these workouts in the pm, as in from lunchtime onward. My rationale is that these types of workouts represent a strong stressor to the cardiovascular system. I feel this stress can be magnified if the workout is done in the morning. Tissue temperature and vessel elasticity do not reach peak levels until early afternoon. This is true no matter how much you warm up or how easily you begin (although those things matter). I’ve always felt this type of training worked best when done later in the day. Conversely, hard intervals in the morning may not be the best for either your conditioning or your long term health. While this may seem controversial, this is my observation with thousands of clients over 40+ years. I eschew the trend of sunrise gutbuster sessions and pre-dawn HIIT classes. This does not make evolutionary sense.
Where should you do a VO2max workout? Two responses here: environment and placement in your Annual Training Plan (ATP). The location where you do your VO2max workout should be one that is relatively free of distraction. A place that allows you to focus, concentrate, and monitor (whether by feel or device) your effort. A treadmill, an exercise bike, a track, a field…any area that is not chaotic and which fosters your ability to be relatively precise in your actions. This is because VO2max intervals require perhaps the highest amount of concentration in the training arena. Sure, you can do more explosive things which have a higher intent requirement, but they are generally much more brief. The net challenge of the VO2max grind (I don’t love that word) is highest. Make your setup fit the circumstances.
As far as when you emphasize these sessions in your year, the answer is “it depends…but most of the time.” Obviously, if you’re in a phase which is really working on speed or strength, save most of your energy for those things and downregulate your VO2max work during that time period. The intelligent and comprehensively trained athlete loses very little when taking a periodic break from a training method. Likewise, during post-seasons or dedicated recovery windows, don’t worry about VO2max work. A few weeks, or even a month or two, won’t hurt ya. In fact, it will restore that all-important freshness.
How do I go about setting up a VO2max session? I should reiterate that what you’re getting here is my opinion. However, unabashedly, it is an expert opinion. Tens of thousands of hours of work and personal experience. Multiple degrees and certifications. Diligent ongoing study of the literature. Over one hundred thousand dollars of investment in this education. If you’re an accountant, attorney, biologist, or engineer at the same point in your career, I bet you’re at a similar level. I respect that. But this is my wheelhouse, and thus, I shall pontificate.
Never do VO2max workouts when you’re tired. The session won’t feel good, it won’t stick, and your risk of illness, injury, and burnout will be exponentially magnified. You have to be rested and fresh to tackle these workouts. It’s fine to test your toughness when you feel good, but if your body isn’t ready, postpone the session and live to fight another day. This is being smart…not weak. Full stop.
You’ll need plenty of time for a thorough, progressive warmup. In fact, this is a big mistake that many trainees make, and not all of them are rookies. Going through a gradual warmup process prepares you for those high demands. The prep activates your CNS/PNS, raises tissue temperature and vessel extensibility, and makes going hard feel a little easier. You will experience slightly lower lactic acid production and improved lactate clearance. The session will be more effective and you’ll recover faster.
If you’re doing VO2max intervals, all other forms of training should probably be categorized as ancillary or accessory. This is due to the massive energetic requirements of aerobic capacity work. It’s fine to do a blended session, but if VO2max is present…it should be the priority.
You’ll want to be exceptionally aware of the recovery demands following a VO2max session. Your body will be tired and your metabolism will be dealing with some mild after-shock. Organize your day so you have a mix of light activity and rest following a VO2max session. Avoid scheduling hard labor or other physical challenges immediately after your workout. Remember, the workout is the stimulus but the recovery window allows for the adaptation.
Why do I need to be aware of effort during VO2max training? The adaptations from this type of exercise are greatest in the range above the anaerobic threshold and below the maximum anaerobic power limit. Zone-based effort ratings are quite valuable in this regard and the 5-zone model is most common. In this case, VO2max is most accurately represented by Zone 4, and this roughly correlates with the aforementioned range of 85-95% MHR. The lower end of the heart rate range is typically paired with longer duration intervals, e.g. 5+ minutes, while higher heart rates can usually be sustained/tolerated with shorter work bouts.
You can certainly utilize a heart rate monitor when performing this type of training. You can also go by pace, feel, etc. The talk test is a very useful tool in this application. If you’re trying to peg Zone 4, you are typically only capable of communicating with a few words. A very short phrase, an incomplete sentence, or a 2-3 word response. An example would be if a training partner or coach asked you to describe your opinion on comprehensive training during a rep (they should not do this of course)…you would say “not right now.” If you can talk in complete sentences, you may need to push it just a little more. If there’s just no way you want to speak at all…ease up a tad.
VO2max training sessions work best when the rest intervals are roughly equivalent to the work bout duration. This means that you go easy for about as long as you went hard. For example, the very popular Norwegian Protocol has several interpretations, but the most common is 4 x 4 minutes with 4 minute active rest periods. You go strong for 4 minutes, running or pedaling for example, then you go very easy for the same amount of time, spinning very lightly or walking/jogging. Highly aerobically trained athletes can sometimes use shorter rest intervals, due both to their fitness levels and also in the quest to train their ability to tolerate higher levels of blood lactate, but this is neither necessary nor effective for most Lifetime Athletes.
Keep in mind there are lots of ways to do interval training. Many fitness classes use short bursts with very brief reps. These have value and are a valid training methodology. They just are not optimal if you want to maximize your aerobic capacity.
Should endurance specialists do more of this type of training? Probably. Carefully. If distance running or cycling is your jam, your performance level will have a strong correlation to your VO2max. During base-building periods, you probably don’t need to do these workouts more than once per week. In fact, you might not do them at all when building a low-intensity foundation in your conditioning. But there may be periods in your Annual Training Plan when you may benefit from twice-weekly VO2max intervals. Generally, though, this shouldn’t be sustained for too many weeks in a row without a break. Try to think of absorbing workload more than forcing fitness.
In fact, excessive VO2max training is very hard on your immune system. As with many things, the dose makes the poison, but this stuff becomes kryptonite pretty quickly if it is stacked up. I’ve seen a lot of athletes break down because, in their highly motivated state, they tried to do more of these intervals. I’ve done that myself. More isn’t always better.
As athletes get older, the ability to execute and recover from high volume sessions declines. This can be subtle in the healthy, well-trained individual, but it still happens. Unfortunately despite all our best efforts. So where that Norwegian 4 x 4 protocol looks great on paper, a Lifetime Athlete in her 60’s or 70’s (many of our clients in the App) might instead be better suited with a 3 x 3, or even 2 x 2 session. We must keep our thinking flexible.
Are there risks associated with VO2max training? This brings us to what is perhaps the proverbial elephant in the room. There is a gray area of older endurance athletes developing atrial fibrillation and flutter as well as coronary artery calcification. The data is rather inconclusive regarding the precise causal factors, although it appears elite and lifetime endurance athletes can be 2 to 10 times more likely to develop these problems, compared to the general population.
Obviously, we’re going to need to dive into this more deeply. Should we immediately assume that VO2max training is bad for your heart and you just shouldn’t do it? That actually doesn’t make much sense in the context of the versatile, durable, robust, and resilient human beast. Or should we take into consideration the context of individual genetics, lifestyle, and how that type of training is performed by certain athletes? As you surmised, my viewpoint is more of the latter than the former.
This topic hits close to home for me because when I hold my hands in front of me, I need 8 fingers to count the friends – all high-level endurance athletes – who have experienced the specific cardiopathic problems we’re discussing. 8 people who had an onset of problems in their 40’s and 50’s. 7 are in their 60’s at this time. One is, tragically, no longer with us.
While I readily recognize that no two athletes are entirely alike, my friends and many other successful endurance athletes tend to share certain personality characteristics. They are disciplined and dedicated. They know that consistent application yields results and they are willing to put the work in. They are tough…mentally and physically. In fact one of these guys, a cyclist, told me “I am willing to suffer more than anybody else.” They are usually busy with work and family and tend to be successful in many areas of life. Often they will get up very early to get their workout in before the day accelerates with responsibility. These behaviors are self-reinforcing. They lead to success and identity. Society rewards the early-rising, hard-working warrior and (often) champion.
There are multiple theories regarding the proposed mechanisms for these arrhythmias and plaque formations. Chronic overload, atrial wall stretching and scarring, vessel wall irritation, etc. But I don’t think these serious problems are simply a result of going hard. I don’t even think I’m going out on a limb when I say they are instead the result of going hard too often, over too long of a time period, in suboptimal circumstances. There is much nuance here. But if you think about it, there are a lot of things we do in life and training (stressors) that we deem incredibly beneficial in small to moderate amounts, yet deleterious in high volumes. I can come up with examples from flu shots to saunas to most forms of exercise. When we push the limits of performance, we typically see a deviation from ideal health.
My concern leads to a discussion of inflammation. Small doses of inflammation, such as those in the examples I just provided, can trigger positive, adaptive, beast-building responses in the human organism. But the caveat for successful inflammation exposure is recovery. We have to recover and rebuild from the stress…before we apply more allostatic load to the system. Proper loading (application of inflammation) represents a very mild injury. But excessive load is adding insult to injury. The body can’t catch up. The situation becomes beast-breaking. To the heart in the case of the chronically hard-training endurance athlete. The well-meaning, highly motivated endurance athlete inadvertently overstresses his/her heart. The problem is, you can’t feel it at first and it usually takes decades of training to incur significant damage.
There is data to suggest that these cardiac issues are related to the accumulation of 1,500-2,000 lifetime training hours as a minimum and much more in the case of many athletes. I don’t think it’s quite that simple, as in viewing total training hours as the main proxy. Instead, I’ll put my money on excessive work in Zone 4, often in the early morning, without adequate recovery windows from one session/exposure to the next. Pushing through that fatigue on a regular basis. For years. Cognitively overriding the early warning signals. Being locked into a pattern that worked to some extent when you were younger. And that you believe in wholeheartedly. You’ll fight to the death to defend this pattern. And if this is you, you’re probably pissed off at me for stating these facts. But I sincerely want to help you, so stick around if your pride allows it.
The concern over high intensity training first thing in the morning is an intriguing one. Again, I have to reiterate, exercise is good and training in the morning is fine. As long as you warm up thoroughly, slightly lower your output expectations, save your hardest work for the afternoon, and place lots of relatively easy days between the moderately challenging ones. But if you are inclined to step out of bed, lace up your shoes, head out the door or to the gym in darkness, and start hammering – day after day – pause for thought may be warranted. Or if that’s what you did for 40 years, consider taking a harder look. The major issue with the very hard/very early combo is tissue peripheral resistance (TPR).
When we think of TPR and cold, stiff tissues first thing in the morning…we tend to envision tendons, muscles, and the like. There are two opposing statistics in this regard. Morning exercisers are the most consistent. They get their session done before the day gets going and the training opportunity slips away. They stack up more total hours in a year than those who train at other times. But, they have a higher incidence of overuse injuries. Their “not fully loosened up” connective tissues and joints struggle with inflammation management. But what is often overlooked, and not talked about enough, is that TPR is also elevated in the morning in the cardiovascular system, particularly the blood vessels. Your heart has to work harder to perfuse your body, and itself, in the morning. Starting easy and working your way towards moderate effort is fine. But quickly going to hard, and spending a lot of time there, on most days, can expose your heart to more inflammatory stress than it can tolerate.
So I think that’s at least one of the major problems surrounding this condition that is known as the athlete’s paradox. It is indeed a seeming contradiction. When we think of exercise as good we expect elite athletes to represent the pinnacle of health and fitness. Most of them hit that peak for fitness for quite a while. Some fall short on the health curve. None of the information I’m presenting is a scare tactic. It’s merely information-sharing.
What’s a Lifetime Athlete to do? Now I need to make some recommendations for two groups. The endurance athletes who have developed atrial fibrillation and flutter and coronary artery calcification. And Lifetime Athletes who do not have these conditions.
Whenever a conversation leads to the “that ship has sailed” commentary, things get a little touchy. Runners who have experienced a sequelae of injuries and surgeries leading up to a total knee replacement often need to come to grips with the idea of their running days being over. I know there are some outliers, but in general…this is the case. I can also provide my own example. The shoulder injuries/conditions, surgery, and ultimately total joint replacement I have experienced have made heavy overhead pressing an inappropriate and contraindicated movement pattern. I simply can’t do that anymore. C’est la vie.
Any endurance athlete who has the type of cardiopathic problem we have been discussing should definitely continue to exercise. But they should keep most of it at low intensity with perhaps a smattering of what might be considered moderate effort. This is generally considered safe and the value of exercise is immense even in the presence of disease. You should work closely with your cardiologist on these matters. But you shouldn’t push hard. That’s no longer appropriate. The damage is done and you can make it worse, or even suffer a stroke. It’s hard to move on. I understand that both personally and professionally. But you must.
But if you do not have these diagnosed cardiovascular problems, there is absolutely no reason why you shouldn’t perform VO2max training. And every reason you should. You just have to do it reasonably. By that I mean once every week or two, preferably in the afternoon, following a proper warmup, at a level that is consistent with your abilities, and with a keen eye on recovery. In this manner you get all of the upsides with none of the downsides. Better athletic performance and longevity-supporting functionality. Higher levels of this than you’d have if you skipped VO2max work.
There are numerous tables available which depict poor-fair-good-excellent VO2max ratings based on age and gender. Likewise, there are laboratory-based evaluations as well as self-tests that you can employ to determine your ranking. But simply hitting some aerobic power from time to time will suffice for most of us.
A great place to start is with a polarized training model. 80/20 is very popular and it describes the ratio of easy to hard volume in your training. 80% of your aerobic conditioning work should be at low or easy intensity (Zone 1-2 in a 5-zone model). 20% should be harder, perhaps primarily in Zone 4 but with some Z3 and Z5 as well. Each of us is a little different and our focus tends to shift throughout the year. Maybe your ratio will be 77/23 or 91/9. There’s nothing magic about 80/20. Feel free to explore and customize. The great value here is that an approximately 4:1 easy to hard ratio develops excellent fitness…and health. This is true to a greater degree than just doing all easy training, or only HIIT classes (despite popular but incorrect media messages).
Designing your comprehensive fitness for life programming, established within an Annual Training Plan, can take on many forms. Finding ways to safely perform VO2max training, and balance it with all the other capacities of athleticism, can be a relatively easy and fun process. We have all of this built into our Training Tribe programming within The Lifetime Athlete App. It’s certainly one way to achieve outstanding results. But it just might be one of the absolute best systems for the forward-thinking, evolving human who truly wants to be Hard to Kill.