How to Upgrade Your Brain, Optimize Your Body and Defy Aging

In his new book, “Boundless: Upgrade Your Brain, Optimize Your Body & Defying Aging,” Ben Greenfield details his best longevity hacks. “Boundless” is a great title, as the object of longevity isn’t just about tacking on years of life, but finding ways to remain healthy and vibrant for as long as possible. In other words, it’s about quality and not just quantity of life.

Greenfield’s goal with this book was to share his best tips for how to improve your energy in every sense of the word. At 640 pages, it’s a hefty book with a higher price to match. For those looking for true and tested advice, though, it’s a treasure trove well worth the price tag.

As Greenfield notes on his website,¹ it’s “a complete guide to optimizing the human body, mind and spirit — written with no stone unturned, no fluff, no ‘watered down’ drivel — just pure, hardcore, practical, from-the-trenches content.”

The original manuscript was 1,200 pages, and deleted sections can be accessed on Greenfield’s website (access details for each chapter are included in the book), where you’ll also find all of the references (about 3,000 of them), which also didn’t make it into the printed book due to the sheer volume of information included.

“I wanted to write the kind of book that I like to read, a big, meaty book that you don’t just read and toss aside, but that you use as a reference for a long time, maybe keep on your coffee table,” Greenfield says.

“I wanted it to be pretty, have good illustrations, be fun to thumb through. And also, unlike previous books I’ve written, not just focus on things like athletic performance or six-pack abs, muscle or fats, but a lot of the stuff that I think is more important: your relationships, anti-aging and longevity tactics, spirituality and purpose in life.

I kind of snuck in and tried to dump some of the woo-woo stuff onto the whole fitness, wellness crowd as well, because sometimes I think we’re striving to feel good and to look good, we think that that’s what’s going to bring us happiness, when in fact … it’s relationships and big family dinners and optimizing your purpose in life — things that, I think, sometimes get neglected in this whole chatter about wellness.”

Mitochondrial Capacity and Lactic Acid Tolerance

One of the best features Greenfield brings to the table is his commitment to staying fit and the strategies to achieve that. Having reserve muscle mass is a widely-underappreciated benefit in case you get sick or hospitalized, and the risk of that certainly increases with age. Greater muscle mass actually improves your chances of survival. Greenfield notes:

“Yes, muscle is important … We know that, for example, grip strength is associated with longevity and other elements of fitness, such as walking speed or maximal oxygen uptake (VO2 max) … Staving off sarcopenia and staving off the osteopenia or osteoporosis that might come with sarcopenia is absolutely important as well.

It is something that is much easier to accomplish before you begin to get into your senior years, although research has since kind of dispelled the notion that you can’t build muscle as you age. You can maintain muscle as you age and can actually increase muscle …

The main elements you want to focus on that I explore in more detail in the book, are mitochondrial density and biogenesis, which we know are best achieved through very brief spurts of exercise … followed by long rest periods, or like a 3-to-1 or 4-to-1 rest-to-work ratio.

We’re talking about one single session a week where you might do 30 seconds all out, followed by four minutes of recovery. You could do that for several rounds. Another [target], in addition to the mitochondria, would be [lactic acid] tolerance, which is often in physiology called muscle endurance.

This would be your ability to buffer lactic acid … Probably one of the better examples of [exercises that improve your endurance] would be the classic Tabata set, a 2-to-1 work-to-rest ratio. This is something that, unlike mitochondrial workout, would be something you would need to do about two to three times a week.

You could use it as an introduction or as a finisher to a strength training workout, for example, if you want to really prioritize your time. But a Tabata set is just about four minutes in length. It is eight rounds of 20 seconds as hard as you can go with 10 seconds of recovery, preferably using a full-body modality, like an Airdyne bicycle, burpees or one of the elliptical trainers, where you’re using both your arms and legs …”

Maximal Oxygen Uptake and Power

A third parameter, in addition to mitochondrial capacity and lactate tolerance is your VO2 max. To target and improve your VO2 max, you’ll want your training sessions to be longer, about four to six minutes in duration with four to six minutes of recovery in between, for a 1-to-1 work-to-rest ratio.

“In my opinion, this is the hardest of them all,” Greenfield says. “Going hard for four to six minutes then recovering for four to six minutes, then going hard for four to six minutes. You do that about four to six times.

You’re talking about exercising for at least 30 minutes and sometimes for 45 to 50 minutes for your VO2 max session. But if you really want to improve it, that’s the way that you get your maximum oxygen utilization up.

We’ve got those three parameters of your physiological fitness. And then you also have a few others. One would be your power. The power is going to be different than the muscle mass because if you’re looking at your fast twitch muscle fibers, mass is not necessarily synonymous with power.

Mass is good for bone density. It’s good for strength. It’s good for being a glycogen container. But you also want functional power.

The best way to do that in my opinion, if you want to stay injury-free for life, is … bodyweight training done in a very fast explosive manner or with a very light medicine ball [or] sandbag a couple of times a week. Kettle bells are wonderful for this as well. A perfect example would be The New York Times seven-minute workout.²“

Strength and Stamina

Two additional fitness parameters that need to be addressed in a targeted manner are strength and stamina. Stamina basically refers to your fat-burning efficiency: your ability to exert yourself for long periods of time.

For stamina, Greenfield recommends taking a 1.5- to three hour-long walk, bike ride or paddle session — anything where your body is engaged in chronic repetitive motion for a long period of time — preferably in a fasted state, once a week. Alternatively, do 20 to 30 minutes of fasted cardio followed by a cold shower.

To improve muscle strength, Greenfield favors super-slow weight training, advocated by Dr. Doug McGuff. Alternatives include elastic band training systems and blood flow restriction (BFR) training, which is my personal favorite. Greenfield likes to combine BFR with super-slow training once or twice a week. More recently, McGuff has also embraced BFR in combination with super-slow training.

“When you add all that stuff up — [the exercises for] mitochondrial density, lactic tolerance, the VO2 max, the stamina, the power and the muscle building, it sounds like a lot. But really, you can do all that with the time commitment of about 45 to 50 minutes a day, plus that one longer session on the weekend.

It’s a sustainable scenario for life, for busy people, that hits all those different physiological parameters. You’re not leaving something off the table, whether it’s your VO2 max or mitochondrial density or what have you. And then … if you really want to put on muscle, I found … a lot of nutrients that I think help quite a bit.

In the evenings, I always do a 12- to 16-hour fast so I get the autophagy. And then I do other things for [to trigger] hormesis or autophagy, like a lot of sauna, a lot of cold [exposure], those long-fasted walks in the morning.”

As for nutrients, three supplements Greenfield recommends for optimizing muscle growth are:

While these may sound like supplements a pro athlete might use, aging individuals who want to put on muscle can reap equal benefits. The same goes for the exercise routines described above. Greenfield notes:

“That entire workout routine that I just described is in no way something I’ll give to a professional athlete. I’ve trained marathoners and triathletes and they’re out on two-hour hardcore bike rides and crushing track repeat workouts that last an hour or so. What I just described is actually very close to what you would want as a stay-fit-for-life-type of routine.”

Breath Work for Health

In the interview, Greenfield also expounds on the benefits of breath work and breath holding. For all the details, please listen to the interview in its entirety. Why would you want to practice holding your breath? Greenfield explains:

“I do holotropic breath work, similar to what Stanislav Grof developed as an alternative to LSD for merging left and right hemispheres of the brain and taking you to a very cool place, the highest you can get without psychedelics really … I can hold my breath forever. It used to be about three to three and a half minutes on the exhale during holotropic breath work.

I’m up around six minutes now. Same thing when I do my breath hold walks. I’m walking and every time I pass a telephone pole, I see how long I can hold my breath.

I play with all these different breath devices when I’m walking. I have one called the Relaxator, which is based on Patrick McKeown’s work in ‘The Oxygen Advantage.’ It trains you to retain simultaneously elevated levels of oxygen and carbon dioxide.

Based on the Bohr effect, you get more oxygen delivered in the tissue when you do that. Essentially, all it means is that you exhale for a far longer period of time than you inhale.

The Relaxator [device] that you put in your mouth is basically like a resistance device where you breathe in through your nose, and then as you breathe out through your mouth, it’s almost like you’re breathing out through a straw or through very pursed lips.

You can go for a whole walk where you have this thing in your mouth … Your breathing just feels clear, crisp, clean and full when you’re using that thing on a regular basis. I certainly noticed a dramatic effect from that.”

The Oura Ring and Other Fitness Devices

Certain technologies and wearable devices can be quite helpful and motivating when you’re changing or trying to improve your lifestyle and health. Greenfield was one of the first to adopt the Oura ring, which he purchased at a biohacking conference in Finland.

“I was looking for something that would track my sleep cycles and also be able to be put in airplane mode,” he says. “I wound up buying one there at the conference and travelling with it back to the States. It was shortly after that that I wore it to some conference … where a lot of people asked me about it …

I like it. It gives me good data. What I use the most is the sleep data, and I find the step count data to be very motivating … I take at least 15,000 steps a day, because that’s my marker for myself and it’s very easy for me now to check at the end of the day.

If I’m at dinner and I look at my ring, which I do, and I haven’t had my 15,000 steps, I go for a walk after dinner. I find it highly motivating. It sounds silly, but for step counts and for sleep tracking, I find it to be very useful.

For heart rate variability (HRV), it gives you decent data, although I still like to get my HRV measurement in the morning using the gold standard Bluetooth-enabled chest strap, lying in my back. I use an app called NatureBeat. It sends both my low-frequency and high-frequency, my sympathetic and parasympathetic nervous system scores to the app.

It allows me to track [my HRV) in real time for about five minutes as I breathe. Since I wake up in the morning and lay there and do a little bit of journaling and breathing anyways, it’s a much more accurate way for me to check my HRV.

But the Oura ring does take a multitude of five-minute readings, when you’re prone in bed overnight. It’s not electrical, so the accuracy is somewhat questionable, but it will give you a ballpark.”

Boosting Mitochondrial Biogenesis With Cold Therapy

Another strategy Greenfield advocates is cold therapy, which stimulates mitochondrial biogenesis.

“I’m a big fan of cold thermogenesis, especially in a fasted state so that you’re able to maximize the conversion of white adipose tissue to brown fat,” Greenfield says. “A little bit of caffeine, capsaicin or green tea in the system beforehand can upregulate that process even more. I’m using cold for two to five minutes almost every day …

I always jump in [cold water] after a workout. Everybody says, ‘You’re going to blunt the hormetic response to exercise.’ But research has shown you’ve got up to 10 plus minutes to do that in order to decrease muscle temperature to the extent where you actually blunt that hormetic effect.

Most of my workouts, because I do a cyclic carbohydrate diet, where I save all my carbohydrates for the evening and my workouts typically occur between about 4 and 7 p.m. … so I’m very insulin-sensitive going into that evening carbohydrate feed where I’ll have my pumpkin, sweet potato, yam, dark chocolate, red wine or what have you.

But when I finish that workout, of course I am aware that working out close to bedtime, the increased core temperature decreases deep sleep cycles, so I always go jump in that cold pool when I finish the evening workout.”

More Information

Greenfield details hundreds of biohacks in “Boundless: Upgrade Your Brain, Optimize Your Body & Defying Aging,” so there’s no shortage of alternatives to pick and choose from. It’s bound to become a staple reference you can go back to again and again in years to come.

We also cover far more ground in the interview than I’ve summarized here, such as his views on stem cell therapy and how he uses hyperbaric oxygen treatment, so to hear more about Greenfield’s personal longevity routine, be sure to listen to it in its entirety.

Greenfield’s website, BenGreenfieldFitness.com, is also an excellent resource for all things health-related, as is his cutting edge podcast, where he interviews a wide variety of leaders in the health and fitness fields.