A Deep Dive into the Optispan Team's Training for VO₂ Max

If you had to choose one number that best predicts how long and how well you will live, it might be your VO₂ max—the size of your aerobic engine. A higher VO₂ max means you can deliver and use more oxygen, which translates to climbing stairs without gasping, keeping up with your kids, or bouncing back faster from illness. At Optispan, we measure it because it is one of the strongest markers of healthspan ever studied, and the best part is, it is trainable at any age. In our latest article, we share why VO₂ max matters so much for longevity, what numbers to aim for, and how our team maintains their fitness with very different but still effective approaches that fir their lifestyle.

VO₂ max: the longevity vital sign we can train

If you had to pick one number to capture how long and how well you are likely to live, VO₂ max would be near the top of the list. Think of it as the size of your “aerobic engine,” how much oxygen your heart, lungs, blood, and muscles can use when you go as hard as you can. More oxygen delivered and used means more power with less strain.

Scientifically, VO₂ max is reported as milliliters of oxygen per kilogram per minute (mL/kg/min). Some labs express it in “METs,” where 1 MET equals 3.5 mL/kg/min. Both are simply ways of describing the size of your aerobic engine. But you do not need the units to grasp the value. A bigger engine lets you do more life with less effort. It means climbing a flight of stairs without panting, carrying luggage, playing with kids, hiking hills, and bouncing back more quickly from illness. These everyday wins depend on aerobic capacity.

At Optispan, we measure VO₂ max directly by having you exercise with a mask that tracks the oxygen you breathe in and the carbon dioxide you breathe out. We test most clients once or twice a year to set precise training zones and monitor progress over time. The first test serves as a baseline, and then the healthspan coach and physician provide clients with tactics that fit into their daily lives to raise cardiovascular fitness. Later in this article you will see some real-world VO₂ max training examples, including Matt's and other team members’ personal routines.

We take VO₂ max seriously because it is one of the most powerful predictors of survival ever measured. In a study of 122,007 adults who completed treadmill tests, the people with the lowest fitness (25th percentile) had about five times the risk of death compared to those in the top 2 percent. The benefit continued to rise as fitness improved, with no upper limit detected.

The penalty for being unfit was as large as, or larger than, well-known risks such as smoking, diabetes, or hypertension (smoking HR ≈ 1.41, diabetes HR ≈ 1.40, hypertension HR ≈ 1.21). For older adults (70 and up) and people with high blood pressure, being in the very-fit group carried extra protection (low vs elite: adjusted HR, 5.04!). Of course, this does not mean that if you have great cardiovascular fitness you have a free pass to smoke or eat all the pastries you want. But the reality is, if you are regularly doing those things, you almost certainly will not have a high VO₂ max.

If the term “hazard ratio” (HR) is new to you, here is the Optispan translation: a hazard ratio compares the chance of an event such as death between groups over time. A higher HR means higher risk. The gap between low VO₂ max and high VO₂ max is not subtle, it is enormous. That is why we talk about banking aerobic capacity in the same way you would bank money, muscle, or bone. Build it now and maintain it, so that future-you can keep doing the things that make life worth living. It is essentially saving for retirement, but with energy and health instead of dollars.

Our first waypoint for every client is the top 25 percent for age and sex, which is labeled “high” on the reference charts. Once you are there, we can aim higher. Some of our clients and a lot of our staff, set their sights on the top 10 percent (sometimes called “superior” or “elite” zone).

10-year survival rate (from middle age, 50s):

• Poor: 77%

• Fair: 91%

• Good: 93.5%

• Excellent: 96%

• Superior: 97%

There are dozens of studies that test different exercise protocols for boosting VO₂ max. Some are tightly controlled and may even point to an “optimal” way to train on paper. But here is the reality: if you cannot stick with it long term, it is not truly optimal for you. Consistency always beats perfection.

That is why, instead of prescribing a single one-size-fits-all program, I want to show you how our own Optispan team approaches cardio. We are five people with very different lives, goals, and preferences, yet each of us manages to keep our cardiovascular fitness at a high level.

You will see a mix of styles, from walking pads and treadmills to intervals, hills, and endurance sessions. Some of us thrive on structured workouts, others on flexibility and variety. The point is not that one method is “best,” but that there are many paths to the same destination. The best protocol is the one you can return to week after week, month after month, and year after year.

So as you read through our routines, notice what feels doable for you. Maybe it is Matt’s approach, or Dr. Byrne’s, or Will’s. The goal is to find a style that fits your life, keeps you engaged, and moves you steadily toward a bigger aerobic engine.

Matt Kaeberlein, PhD

Even though this section is about cardio, let me start with a warning: don’t skip resistance training. Cardio alone, without the strength and muscle you build from resistance work, can be a recipe for problems, even if your VO₂ max improves.

The other preface I’ll give is that my approach to cardio, and exercise in general, isn’t rigid. I like to mix things up, not worry too much about zones, and focus on activities I actually enjoy, like getting outside and hiking or climbing.  Other people find a highly algorithmic approach to be effective. Do what works for you and what is sustainable over the long run.

Ok, so for cardio, my standard “zone 2” workout is ~30-45 minutes on an elliptical in the morning. I usually do this about 45 minutes after waking up. I’ll typically read or do something on my iPad, which passes the time quickly. Sometimes, I’ll mix it up and do treadmill, bike, or – depending on weather and time of year – a walk or ride outside.

For VO2max, I find stairs to be a great way to do intervals.  There’s a set of ~125 stairs near us, that Tammi and I have used for training.  Going up gets the heart rate into Zone 5, then coming down is a rest.  I adjust speed up and down, reps, and even add weight as desired.  Again, being outside I find much preferable to trying to do this kind of high-intensity exercise inside.  Then every once in a while, I’ll just go for a hike with my headphones on and push myself into Zone 4 and 5 most of the way up.  Mt Si or Rattlesnake, near where I live, are great for this. 

And the last piece of my cardio puzzle is the music.  I love music, and I’m a child of the 80s, so my workout playlist is full of all the hair metal classics. 

Dr. Nicki Byrne, MD

I started running back in medical school as a way to manage stress, and it’s been a steady part of my life ever since. For a while I even got into distance running and managed to complete two marathons before having kids. Life definitely shifted after that, but running has stayed my go-to reset button - usually in the form of a comfortable 4–5 mile run.

Now that both of my kids are confident on their bikes, our after-work routine often means heading to the beach: they ride, I run alongside, and it is the perfect mix of fitness and family time. When the weather keeps us inside, I’ll mix it up with Tabata sprints on the treadmill or a Peloton ride. And several times a week you’ll catch me on walking my dog with my weight vest for some added weight-bearing activity.

Speaking of weight-bearing activity…  While cardio and VO₂ max training do wonders for your health, it doesn’t mean you can skip strength training. I fit in three resistance sessions each week: lower body, upper body, and full-body..

Dr. Kevin White, MD

Each week, I typically incorporate one to two high-intensity interval training (HIIT) sessions—most often using the Tabata protocol. Tabata is a specific form of HIIT that involves 20 seconds of all-out effort followed by 10 seconds of rest, repeated for 8 rounds (totaling 4 minutes). Despite the short duration, it's highly effective for improving both aerobic and anaerobic capacity, making it a time-efficient option when intensity is the goal.

In addition to HIIT, I aim for two to three Zone 2 cardio sessions, each lasting 30 to 40 minutes. These are performed at a lower intensity, typically around 60–70% of max heart rate, and are focused on building aerobic efficiency, mitochondrial health, and overall endurance.

This weekly structure serves as a general framework. It's flexible—some weeks I scale it down or ramp it up depending on travel, recovery, or shifting priorities. The key is staying consistent over time while allowing room for adaptation.

Will Merrick

My weekly cardio routine is designed to hit a range of heart rate zones and aerobic capacities, with an emphasis on consistency, variety, and overall enjoyment. I typically anchor the week with a longer, low-intensity Zone 1–2 session on the weekend—usually a hike or ruck covering 6 to 10 miles. This serves as my endurance base and provides time outdoors while keeping my heart rate in a sustainable fat-burning zone. During the weekdays, I aim to include one higher-intensity session—often a tempo run, sprint intervals, or a HIIT-style workout. These workouts usually last 30 to 40 minutes and push me into Zone 3 and Zone 4 heart rate ranges. While I occasionally use the Norwegian 4x4 protocol, I tend to prefer tempo intervals with shorter bouts of effort (30 to 60 seconds, sometimes up to 2 minutes) paired with equal recovery, repeating for 8 to 12 rounds depending on the format.

In addition to the long weekend session and the intensity day, I try to fit in one more moderate-intensity Zone 2 cardio session during the week—usually 30 to 45 minutes. This might look like a brisk walk with a weighted vest or incline treadmill work at around a 9% grade and a speed of 3.5 to 5.5 mph, depending on the zone I want to target. I also occasionally incorporate stationary bike rides for cross-training, especially when I want to give my joints a break or add variety. These are usually steady-state Zone 2 efforts, but I’ll sometimes use the bike for a high-intensity Tabata-style session when I want to spike my heart rate without the impact of running.

Outside of these structured workouts, I prioritize frequent daily movement: lots of walks, mobility breaks, and step accumulation throughout the day to support overall energy expenditure and recovery. While my weekly goal is roughly 250 minutes of cardio (multiple studies show diminishing marginal returns after 300 minutes), I’m not overly rigid about hitting exact zone breakdowns—I focus most of my efforts in Zone 2 with the somewhat regular higher intensity workout, but rarely more than one of those per week.

Matthew McCool

My weekly workout routine is designed to balance high and low intensity cardio with strength training and active recovery, supporting both performance and long-term health. I typically begin the week with a full-body kettlebell interval workout at high intensity. This combines cardiovascular conditioning with muscular endurance, stability, mobility, and coordination.

On Tuesdays, I shift to a focused weight training session, complemented by 10,000 steps throughout the day. Wednesdays are dedicated to a mid-distance run, typically between 5 to 7 miles. This aerobic effort improves VO₂ max, cardiac output, while also helping me with mental clarity through endorphin release and stress regulation. Thursdays and Fridays mirror Tuesday’s structure, with weight training and 10,000 steps.

On Saturdays, I either wear a weighted vest and complete stair intervals—usually six sets—or head to the gym to play basketball. Stair workouts with added load build strength and lower limb power, while basketball enhances agility, reaction time, and social engagement, all of which elevate my cognitive and cardiovascular health. Sundays are reserved for active recovery. I aim to get 10,000 steps but avoid structured training to allow my body to reset. Overall, my routine aims to be versatile and aid recovery balance, which are essential for sustainable performance and longevity.

Nick Arapis, CSCS

My favorite modality for cardio is the walking pad or treadmill. I love the versatility and how easy it is to adjust intensity. As I type these words, I am walking on my walking pad at a 4 percent incline and 4.0 mph, which gives me a heart rate around 130 beats per minute. That is a comfortable effort, not quite my usual Zone 2 threshold. To reach Zone 2, I typically need closer to a 10 percent incline at the same speed.

I think of the treadmill as having three “levers” you can pull to adjust difficulty:

1.      Speed – the most obvious way to increase effort (METs).

2.      Incline – raising the grade to drive heart rate higher without needing to sprint.

3.      Load – adding weight, for example using a weighted vest. I sometimes wear a 20-pound vest to make the workout more challenging without increasing incline or speed.

By experimenting with these three levers, I can find the right combination to keep my heart rate in the desired zone.

In terms of overall training, I do cardio three to four days per week. One of those sessions is higher intensity, where I use intervals that push my heart rate close to max, often 190+ beats per minute. The other days are more steady state. Alongside cardio, I also do resistance training three times per week. I make sure to hit every muscle group twice per week, with a focus on intensity rather than sheer volume. With two young kids at home and a busy work schedule, I want to maximize the effectiveness of my time in the gym.

This may be the bias caused by my exercise science background speaking, but VO₂ max deserves a top spot alongside muscle mass (measured by DEXA) and grip strength (measured by dynamometer) as a healthspan vital sign. It is not just a performance metric, it is a powerful and modifiable indicator of how long and how well you will live.

The good news is that VO₂ max is trainable at any age. Even modest climbs up the fitness ladder deliver steep drops in risk. Our playbook is simple: build a wide base by moving often, touch the peak weekly with intense workouts, retest, and repeat. Aim for the top 25 percent for your age and sex. From there, if you want to keep climbing, chase the top 5 percent.

The payoff is not just years added to life, it is life added to years.

Nick Arapis, CSCS, CMES