The Four Kinds of Exercise



In 2019, I wrote a blog post titled How I Started Going to the Gym based on Alex Hutchinson’s book Which Comes First, Cardio or Weights? That marked the beginning of a four-year journey that has fundamentally changed my life. It has also turned me into that most annoying of creatures: an evangelist. I’m constantly trying to convince everyone I know that they should be exercising more and exercising better. It is a hard sell. People who don’t exercise feel like they don’t have the time, and people who already exercise don’t like being told that they are doing it wrong. But here’s the thing: almost everyone I know over the age of 35 is suffering in some way, and I’m confident that the right kind of exercise can help.

This is why I’m so enthusiastic about Peter Attia’s bestselling book Outlive: The Science and Art of Longevity. It makes a strong case for exactly the exercise regime I’ve been advocating for others my age. But I was wrong if I thought I could just point people to the book and be done with it. Unfortunately, the book is long-winded and it’s hard to sift through it for clearly stated advice. Hopefully, this blog post can offer a useful starting point.

I have to be honest though; Attia’s recommendations will seem excessive if you aren’t already active. He wants us to be doing a lot of exercise: a combination of strength training, two different kinds of cardio, and what he calls stability” training! But there are good reasons for recalibrating your life to make time for this, and he lays them out very clearly.

How Much Exercise?!

Before we go any further, just how much exercise are we talking about?

The book doesn’t provide a clear statement of his minimal recommendations, but I found a blog post that does:

So, he’s talking about dedicating 7-9 hours a week to exercise. That’s a lot, especially if you’re already working a full week. But if you’re largely sedentary, any amount of exercise will bring tremendous benefits. You shouldn’t give up just because you don’t have the time. Even one hour a week can be life-changing! Start slowly with a routine you can manage now and build on that. Think of this post as a set of long-term goals, not a starting point.

Also, it’s the zone 2 cardio that is the most time-consuming, and that can be combined with other activities you may already be doing. For instance, I get my zone 2 cardio while walking the dog, something I already do daily. You could also get it from biking to work or even while watching TV. It really isn’t that hard if you know exactly what you are trying to do. (More on that later.)

Nor do you have to follow Attia’s routine exactly. You can use this information to craft your own. My routine looks like this:

The key is to ensure that you are getting all four kinds of exercise. Most active people I have spoken to about this are only getting one or two of these and almost none of the others. I think this explains why so many of them still struggle with various aches and pains, even if they are otherwise physically active. For instance, I have a friend who is an avid bicyclist. She gets plenty of cardio, probably mostly in zone 2, but she does no strength training or stability work. It is important to understand all four kinds of training (and their purposes) in order to plan your own exercise routine but, before that, I want to first examine the reasons why we need to do so much exercise in the first place.

Why Exercise So Much?

As I mentioned in my initial post on Outlive, the title is misleading. To the extent that the book is about living longer, it is really about avoiding the things most likely to kill you prematurely. The real focus, though, is on living better, not longer. The diseases of old age might not kill you, but they can make your last few decades on earth miserable. Getting fit will enable you to spend more of those years engaging in the activities you enjoy.

In that post I shared a chart showing that being fit significantly reduces the risk of dying early. Attia cites a study of 750,000 U.S. veterans which showed that Being unfit carried a greater risk than any of the cardiac risk factors examined.” (Those risk factors being: chronic kidney disease, smoking, diabetes, cancer, cardiovascular disease, and hypertension.)

Much of the first half of the book is an extended argument about why this might be so. In a nutshell, he argues that metabolic dysfunction is a factor in the main killers of adult non-smokers, such as heart disease, cancer, neurodegenerative diseases (e.g., Alzheimer’s), and diabetes. Both strength training and cardiovascular exercise play an important role in reducing metabolic dysfunction. I was surprised to learn that muscle may be almost as powerfully correlated with living longer” as cardio fitness.

You can’t count on living longer. Even if you do everything right, a lot of things can kill you. Exercising, because it gets you outdoors more, might increase your risk of getting hit by a car. That’s why I want to focus instead on the second part of Attia’s argument: improving our quality of life during our later years.

This graph shows how cardio fitness declines with age. The same kind of rapid decline also happens with strength and stability as we age.

But the graph also offers hope. That’s because our decline is relative to where we are now. By improving our current fitness level, we can ensure that we remain more fit later on. But that means that, if you want to be able to do what you currently consider fairly ordinary” activities, such as taking a short hike, or taking luggage out of an overhead compartment on a plane, you need to train like an athlete now.

As the chart shows,

athletes had the aerobic capacity of people decades younger than them, while the men in the control group had declined so far that they were on the verge of losing their ability to live independently

This is why you want to spend so much time exercising. Not because it will necessarily help you live longer (though it might), but because it will help you live better. And it isn’t enough to just exercise more; we also need to exercise better. Even if the total amount of exercise Attia recommends seems like a lot, the goal here is really to identify the absolute minimum amount of exercise necessary to stay healthy and active as we age. To do that, we also need to be getting the right kinds of exercise and doing them correctly.

The Four Kinds of Exercise

The Two Types of Cardio

I’ve already mentioned the terms zone 2” and VO2 max” a couple of times, but these terms need explanation. They refer to two different types of cardio exercise based on a standard scale that rates cardio intensity. Zone 2 is essentially

going at a speed slow enough that one can still maintain a conversation but fast enough that the conversation might be a little strained.

While VO2 Max is

the maximum rate at which a person can utilize oxygen. This is measured, naturally, while a person is exercising at essentially their upper limit of effort . . . The more oxygen your body can use, the higher your VO2 max.

As mentioned above, Attia recommends several hours of zone 2 exercise each week, but also one short session focused on increasing your VO2 Max capability.

Zone 2

I previously thought that, with all the walking I do each week with the dog, I must be getting a of low-level cardio, but it turns out it’s mostly in zone 1, which isn’t good enough. We need zone 2 training to help improve our mitochondrial health.

The healthier and more efficient your mitochondria, the greater your ability to utilize fat, which is by far the body’s most efficient and abundant fuel source.

By contrast,

People with obesity or other metabolic problems will tend to have much higher resting lactate levels, a clear sign that their mitochondria are not functioning optimally, because they are already working too hard just to maintain baseline energy levels. This means that they are relying almost totally on glucose (or glycogen) for all their energy needs—and that they are totally unable to access their fat stores.

The good news is that by doing lots of zone 2 cardio we can change the quantity and functioning of our mitochondria. And it isn’t that hard either, but you do need to put some thought into it. (You don’t want to be doing zone 3, because that will actually undermine your training, making it harder for your body to expel the lactic acid that builds up while exercising.)

To upgrade my dog walks from zone 1 to zone 2, I strap on a backpack with some extra weight. (This is called rucking). I track this using an app called Zones. Here’s a recent workout:

VO2 Max

According to the study of veterans mentioned above, a person with poor VO2 Max for their age carries a greater relative risk of death than smoking.” And someone in the bottom quartile of VO2 Max fitness for their age is nearly four times likelier to die than someone in the top quartile.” That means that

even just climbing from the bottom 25 percent into the 25th to 50th percentile (e.g., least fit to below average) means you have cut your risk of death nearly in half, according to this study.

Doing lots of zone 2 exercise can improve your VO2 Max, but Attia recommends specifically training your VO2 Max for at least one session a week.

He suggests the following protocol:

Where HIIT intervals are very short, typically measured in seconds, VO2 max intervals are a bit longer, ranging from three to eight minutes—and a notch less intense. I do these workouts on my road bike, mounted to a stationary trainer, or on a rowing machine, but running on a treadmill (or a track) could also work. The tried-and-true formula for these intervals is to go four minutes at the maximum pace you can sustain for this amount of time—not an all-out sprint, but still a very hard effort. Then ride or jog four minutes easy, which should be enough time for your heart rate to come back down to below about one hundred beats per minute. Repeat this four to six times and cool down.

Importantly, you need to allow time to recover in-between each set, as well as spending time to warm up and cool down properly before and after each workout.

I don’t currently do his recommended VO2 Max routine. Instead, I do a more conventional HIIT bodyweight workout with my Nike Fitness app. Over time I’ve been seeing my ability to sustain zone 5 cardio improve significantly, so I feel like it’s working. Perhaps this is just because I started at such a low level of cardio fitness that it is easy to make gains now. When I stop seeing improvement, I’ll try Attia’s approach.


When it comes to strength training, Attia emphasizes muscle muscle speed and power, not muscle mass. You don’t need to look like Arnold, but you need to replace what you naturally lose as you get older, and build a storehouse to draw upon when we are no longer able to do that.

we lose muscle strength about two to three times more quickly than we lose muscle mass. And we lose power (strength x speed) two to three times faster than we lose strength. This is because the biggest single change in the aging muscle is the atrophy of our fast twitch or type 2 muscle fibers. Ergo, our training must be geared towards improving these with heavy resistance training.

My personal trainer made the point that, if you loose your type 2 muscle fibers, your movements become awkward, increasing the risk of injury. This can help explain why some physically active people who don’t do specialized strength training suffer from so many aches and pains.

While it is never too late to start strength training, it will become increasingly harder to build muscle as you get older. Moreover, genetics play an important role in how effectively we build muscle mass. If you aren’t one of the genetically gifted, it will take time, so you really need to start now. As Attia puts it:

I think of strength training as a form of retirement saving. Just as we want to retire with enough money saved up to sustain us for the rest of our lives, we want to reach older age with enough of a reserve” of muscle (and bone density) to protect us from injury and allow us to continue to pursue the activities that we enjoy.

Attia focuses his training regime on the kinds of functional movements older people need to preserve:

  1. Grip strength, how hard you can grip with your hands, which involves everything from your hands to your lats (the large muscles on your back). Almost all actions begin with the grip.
  2. Attention to both concentric and eccentric loading for all movements, meaning when our muscles are shortening (concentric) and when they are lengthening (eccentric). In other words, we need to be able to lift the weight up and put it back down, slowly and with control. Rucking down hills is a great way to work on eccentric strength, because it forces you to put on the brakes.”
  3. Pulling motions, at all angles from overhead to in front of you, which also requires grip strength (e.g., pull-ups and rows).
  4. Hip-hinging movements, such as the deadlift and squat, but also step-ups, hip-thrusters, and countless single-leg variants of exercises that strengthen the legs, glutes, and lower back.

His reasoning is as follows:

I focus on these four foundational elements of strength because they are the most relevant to our Centenarian Decathlon—and also to living a fulfilling and active life in our later decades. If you can grip strongly, you can open a jar with ease. If you can pull, you can carry groceries and lift heavy objects. If you can do a hip-hinge correctly, you can get up out of a chair with no problem. You’re setting yourself up to age well. It’s not about how much weight you can deadlift now, but how well you will function in twenty or thirty or forty years.

While these are good general goals, everyone’s body is different, hence your individual needs will be different as well. I recommend that everyone schedule some time with a personal trainer, as does Attia. Not only can they help you identify a personalized training regime, but working with a trainer on your form can help prevent injury. A good trainer is expensive, but you don’t need to see them every week forever. I recommend scheduling around 12-24 sessions when you first start, with a few sessions each year to check your form and update your workout.

There are also some excellent online resources for getting started with strength training. Alexandra Redmond’s Instagram account is excellent for women trying to get comfortable in a gym for the first time, and I constantly consult Squat University’s website as well as his Instagram and Youtube channels to help with my form and whenever things don’t feel quite right somehow.


Finally, but perhaps most importantly, Attia places a strong emphasis on stability training. In his own clinical practice he’ll often have people do months of stability training before starting to lift heavy weights. Good stability is key for preventing injury. Attia’s definition of stability is the ability to

create the most force in the safest manner possible, connecting our body’s different muscle groups with much less risk of injury to our joints, our soft tissue, and especially our vulnerable spine.

This is much more than simply having strong core” muscles, but making sure that we are properly engaging all the key muscles for each kind of movement. You need to brace your core, yes, but you also need to make sure your glutes are firing before you do a squat. There a number of quick exercises you can do before each kind of workout to help do this. One that Attia recommends in particular is the step up”:

Squat University (see above) has many more such stability exercises you can do, as well as advice on figuring out which kinds of stability exercises are right for you.

I was happy to see Attia also recommending something called DNS, or dynamic neuromuscular stabilization. My own personal trainer has had me doing DNS exercises for a year now and I have found them quite helpful.

DNS originated with a group of Czech neurologists who were working with young children with cerebral palsy in a hospital in Prague in the 1960s. They noticed that because of their illness, these kids did not go through the normal infant stages of rolling, crawling, and so forth. Thus they had movement problems throughout their lives. But when the children with cerebral palsy were put through a training” program consisting of a certain sequence of movements, replicating the usual stages of learning to crawl, sit up, and eventually stand, their symptoms improved and they were better able to control their motions as they matured. The researchers realized that as we grow up, most healthy people actually go through an opposite process—we lose these natural, healthy, almost ingrained movement patterns.

Proper breathing is especially important for strength training. Attia has a decent video tutorial on some basic DNS breathing exercises as well:


That covers Attia’s four kinds of exercise, but I think he makes a mistake by not including a fifth kind: mobility training. He fudges by including it under stability, but I’ve come to think that mobility needs to be thought of differently. Stability training is largely about stiffening your core so as to be able to exert strength, but mobility training is about being able to exert strength while moving. For that reason, the kinds of exercises you need to do for each can be quite different, though there is a lot of overlap.

As you get older and lose mobility in your joints, specialized training can help you restore at least some of that lost mobility. In this sense mobility training looks a lot like rehab or physical therapy, and basically it is. But since you do it even when you don’t have an injury, some people call it prehab.”

Personally, I do a combination of focused prehab exercises as well as incorporating elements of both stability and mobility work into my regular workouts, so I’m basically doing something every day. Earlier in my blog I chronicled my movement away from yoga towards this new approach, but yoga could certainly be an important part of any such routine. (Though I would now want to do a more flow-based yoga, rather than the more static Iyengar style I was doing before.) What I really like now is something called animal flow which combines elements from different bodyweight disciplines such as breakdancing, parkour, gymnastics, [etc.]” I incorporate a lot of animal flow into my twice-weekly body weight workouts.

While you would be best off seeing a physical therapist to get recommendations on what kinds of focused prehab exercises you should be doing, there are now some great resources on YouTube and Instagram. These are two of my favorites:

More from Outlive

That wraps up my summary of Attia’s exercise recommendations. There is obviously a lot more detail in the book. If you don’t want to read the whole thing, you can just jump to the third part of the book, where much of this is taken from. If I have time I hope to write another post summarizing some of his recommendations from Part II.