Executive Insight

Executives routinely track performance indicators.

Revenue. Cash flow. Growth. Productivity. Market share. Investment returns.

When it comes to their own health, however, many people operate with surprisingly little objective information.

They may know their weight.  They may know their cholesterol.  They may track their steps, resting heart rate, or sleep.  But there is another number that deserves considerably more attention...particularly as we move through our 40s, 50s, and 60s:

Cardiorespiratory Fitness.

One of the best laboratory measures of cardiorespiratory fitness is VO₂ max, or maximal oxygen uptake.  In practical terms, VO₂ max reflects the body's maximum capacity to take in oxygen, transport it through the cardiovascular system, and use it at the working muscles during increasingly demanding exercise.

That sounds like a metric designed for cyclists, marathoners, and professional athletes.

It isn't.

Cardiorespiratory fitness is relevant to anyone who wants to remain capable, energetic, resilient, and independent as they age.

In fact, the American Heart Association has argued that cardiorespiratory fitness should be considered a clinical vital sign because of its strong relationship with cardiovascular disease, overall health, and mortality risk (Ross et al., 2016).

A 2024 overview published in the British Journal of Sports Medicine synthesized meta-analyses representing more than 20.9 million observations across 199 cohort studies.  The authors concluded that cardiorespiratory fitness was strongly and consistently associated with morbidity and mortality across a broad range of adult populations (Lang et al., 2024).

Why This Matters

In Executive Performance Brief #001, I introduced the Executive Performance Pyramid: the idea that sustainable human performance is built from multiple interconnected systems rather than one isolated fitness quality.

Strength matters.

Movement matters.

Recovery matters.

Metabolic health matters.

Cardiorespiratory fitness matters.

And one of the mistakes I see people make is assuming that because they lift weights several times per week, play golf or tennis, walk regularly, or attend an occasional fitness class, their cardiovascular system is automatically well developed.

Sometimes it is.

Sometimes it isn't.

The same is true in the opposite direction.  Someone can accumulate large amounts of aerobic exercise while gradually losing muscular strength, power, mobility, or lean tissue.

Human performance isn't about maximizing one physiological quality. It is about developing enough capacity across multiple systems that no single weakness unnecessarily limits the life you want to live.

Cardiorespiratory fitness deserves particular attention because it provides insight into the integrated function of several systems simultaneously.

The lungs must exchange oxygen.

The heart must pump blood.

The vascular system must distribute it.

The blood must transport oxygen.

The muscles must extract and utilize it.

And the mitochondria within those muscles must convert that oxygen into usable energy.

This is why VO₂ max can tell us something broader than simply whether someone is "good at cardio."

It gives us a window into the size of their aerobic engine.

Research Summary: Fitness and Longevity

The association between cardiorespiratory fitness and health outcomes is remarkably consistent.

One of the landmark meta-analyses was published by Kodama and colleagues (2009) in JAMA.  Researchers examined cardiorespiratory fitness as a quantitative predictor of cardiovascular events and all-cause mortality and demonstrated a graded relationship between greater fitness and lower risk.

Since then, much larger datasets have reinforced the relationship.

Mandsager et al. (2018) studied 122,007 adults who underwent exercise treadmill testing at the Cleveland Clinic.  During more than 1.1 million person-years of observation, greater cardiorespiratory fitness was inversely associated with mortality.  The researchers reported progressively lower mortality across higher fitness categories, with the extremely fit group demonstrating the lowest risk (Mandsager et al., 2018).

An even larger investigation by Kokkinos et al. (2022) examined 750,302 U.S. veterans between 30 and 95 years old.  The relationship between fitness and mortality was inverse and graded across age, sex, and racial groups.  Compared with extremely fit individuals, those in the least-fit group had approximately four times the mortality risk (Kokkinos et al., 2022).

Then came the 2024 umbrella review by Lang and colleagues.

Across 26 systematic reviews with meta-analysis, encompassing more than 20.9 million observations, higher CRF was consistently associated with lower risk of premature mortality and multiple chronic conditions.  The authors reported that each 1-MET higher CRF level was associated with an approximately 11%–17% lower risk of all-cause mortality across the evidence reviewed (Lang et al., 2024).

These studies are observational and therefore should not be interpreted as proving that increasing VO₂ max alone causes a particular extension in lifespan.  Fitness is intertwined with physical activity, genetics, health status, lifestyle, and other factors.

But the consistency, scale, biological plausibility, and graded nature of the association make the message difficult to ignore.

Cardiorespiratory fitness is one of the most informative measurable characteristics of physical health.

Fitness Is Not Fixed

Here is where this becomes particularly relevant for executive performance coaching.

A low fitness level isn't simply something to document.

Cardiorespiratory fitness is modifiable.

Kokkinos and colleagues (2023) examined 93,060 adults who completed two exercise treadmill tests separated by at least one year.  Changes in cardiorespiratory fitness were associated with corresponding changes in mortality risk.  Declining fitness was associated with greater risk, while maintaining or improving fitness was associated with more favorable outcomes (Kokkinos et al., 2023).

That's an important shift in thinking.

Instead of viewing VO₂ max as another health statistic, think of it as a performance KPI.

Measure.

Train.

Reassess.

Adjust.

That process should sound familiar to anyone running a successful organization.

What gets measured in business gets managed.  Human performance shouldn't be different.

Aging introduces another challenge.

Aerobic capacity generally declines as we get older.

But the decline isn't necessarily linear.

Fleg et al. (2005) followed healthy adults longitudinally and found that the decline in aerobic capacity accelerated substantially across advancing decades.  The researchers emphasized that preserving adequate aerobic capacity is important because the ability of older adults to remain functionally independent depends partly on maintaining sufficient physiological capacity for daily activities.

This introduces a concept I believe executives should understand:

Physiological Reserve

Imagine two 50-year-old executives.

Both can walk through an airport.

Both can climb a flight of stairs.

Both can carry groceries.

Both can complete an average workday.

From those activities alone, they might appear similarly capable.

But suppose one possesses considerably greater aerobic capacity.

Now increase the demand.

Several flights of stairs.

A long travel day.

Walking ten miles through a European city.

A mountain hike.

A demanding tennis match.

A poor night's sleep followed by a full day of meetings.

An illness.

Or simply another 20 years of aging.

The difference becomes more apparent.

One person is operating closer to his or her physiological ceiling during ordinary tasks.  The other has more capacity in reserve.

That reserve matters.

The objective after 40 isn't necessarily to chase elite endurance numbers.

It's to build enough capacity that ordinary life remains comfortably below your maximum.

Coach's Perspective

After more than two decades of coaching, one thing has become increasingly clear to me:

Looking fit and being physiologically fit are not always the same thing.

I've worked with people who were strong and muscular but became surprisingly winded during sustained conditioning.  I've also coached people who could spend an hour performing steady-state cardio but lacked strength, muscular capacity, movement quality, or the ability to produce force.

Neither represents complete human performance.

This is why my philosophy has evolved beyond simply asking:

"Did you work out this week?"

I am much more interested in questions like:

• What are we trying to improve?
• What adaptation are we creating?
• How is your body responding?
• What does the data tell us
• What physical qualities will matter to you ten or twenty years from now?

High-performance sport has operated this way for years by using profiling, benchmarking, training-load monitoring, testing, and individualized programming rather than simply accumulating workouts.  NSCA's sport-science framework specifically emphasizes key performance indicators, profiling, benchmarking, and monitoring training response as part of the performance process.

An executive isn't a professional athlete, but I believe there is enormous value in borrowing the process of high performance.

The Executive Aerobic Engine

For most busy professionals, building cardiorespiratory fitness does not require marathon training.

I prefer to think about aerobic development through four complementary layers.

1. Daily Movement

Before discussing sophisticated interval protocols, we should acknowledge the foundation.

Move more.

• Walk.
• Take the stairs.
• Break up prolonged sitting.
• Walk between meetings when possible.
• Walk after meals.

Choose movement when convenience isn't necessary.

Daily movement isn't identical to structured cardiorespiratory training, and accumulating steps does not automatically maximize VO₂ max.

But it establishes the behavioral and metabolic foundation on which higher-intensity training can be built.

2. Build the Aerobic Base

A significant portion of aerobic training can be performed at sustainable intensities.

Today, people commonly call this Zone 2 training, although definitions of "Zone 2" vary depending on whether someone is using heart-rate zones, ventilatory thresholds, lactate thresholds, or consumer wearable algorithms.

That distinction matters.

Rather than becoming obsessed with an exact wearable-generated number, the practical objective for many people is sustained aerobic exercise at an intensity that can be maintained for a meaningful duration without creating excessive fatigue.

• Walking uphill.
• Cycling.
• Jogging.
• Rowing.
• Elliptical training.
• Swimming.
• Rucking when appropriate.

The modality matters less than creating the desired physiological stimulus while choosing something the individual can perform consistently and safely.

3. Raise the Ceiling

The aerobic base is important.

But if improving VO₂ max is the specific goal, eventually we need to challenge the upper end of aerobic capacity.

This is where appropriately programmed interval training becomes valuable.

A systematic review and meta-analysis by Milanović et al. (2015) examined 28 controlled studies involving 723 healthy young-to-middle-aged adults.  Both traditional endurance training and high-intensity interval training substantially improved VO₂ max, while interval training produced a somewhat greater average improvement (Milanović et al., 2015).

Similarly, Weston et al. (2014) reviewed high-intensity interval training among individuals with lifestyle-induced cardiometabolic disease and found meaningful improvements in cardiorespiratory fitness, demonstrating that interval-based approaches can be powerful when appropriately prescribed.

But this does not mean everyone should begin doing all-out sprints.

Intensity must be earned and individualized.

• Training history matters.
• Orthopedic health matters.
• Cardiovascular risk matters.
• Recovery capacity matters.
• Medication use matters.
• Current fitness matters.
• The exercise modality matters.
• And the difference between high intensity and reckless intensity matters.

For some executives, intervals may mean running.

For another, an incline treadmill.

For another, a bike or rower.

4. Recover and Adapt

Harder isn't automatically better.

Exercise creates the stimulus.

Recovery allows adaptation.

If someone combines intense cardiovascular training with heavy resistance training, inadequate sleep, business travel, caloric restriction, high occupational stress, and little recovery, adding even more intensity isn't necessarily intelligent programming.

This is where coaching becomes more nuanced than simply prescribing workouts.

Training must fit within the total stress load of the individual.

High-performance training literature has long emphasized monitoring training response and recovery rather than considering each workout in isolation.  High-Performance Training for Sports, for example, devotes specific attention to monitoring training response, aerobic capacity, energy-specific programming, and effective recovery.

The executive athlete needs the same principle:

Research Summary: You Don't Need to Become Elite

One of the most encouraging findings in the CRF literature is that the largest practical opportunity may exist among people starting at lower fitness levels.

The American Heart Association's scientific statement notes that moving out of very low fitness categories is associated with substantial differences in health risk (Ross et al., 2016).

That changes the objective.

You don't need the VO₂ max of a Tour de France cyclist.

You don't need to run a marathon.

You don't need to train twice per day.

And you don't need every workout to leave you lying on the floor.

For many adults, the first objective is simply:

Move from low fitness toward moderate fitness.

Then:

Move from moderate toward good fitness.

Then decide how much additional capacity makes sense for your goals, schedule, health status, and interests.

Performance coaching should be about progress, not comparison with elite athletes.

Performance Metric: VO₂ Max

What it measures

VO₂ max represents maximal oxygen consumption during progressively demanding exercise and is typically expressed as:

mL/kg/min

Gold-standard measurement

The most direct method is a cardiopulmonary exercise test (CPET) using respiratory gas analysis during progressive treadmill or cycling exercise.

The participant wears a mask or mouthpiece while oxygen consumption and carbon dioxide production are measured as exercise intensity progressively increases.

This provides much richer information than simply looking at heart rate.

What about wearables?

Smartwatches and fitness trackers can estimate VO₂ max or cardiorespiratory fitness using combinations of heart rate, pace, workload, demographics, and proprietary algorithms.

These estimates can be useful for tracking trends.

But they are still estimates.

They should not automatically be considered interchangeable with directly measured VO₂ max.

What about field testing?

Submaximal treadmill tests, walk tests, step tests, running tests, and other protocols can estimate aerobic fitness without laboratory gas analysis.

For many coaching environments, these can be practical tools when appropriately selected and standardized.

The key is consistency.

Use the same protocol.

Control the testing conditions as reasonably as possible.

Record the result.

Train.

Retest.

Look for meaningful trends.

METs: The Number Executives Should Also Understand

There is another useful way to express exercise capacity: METs — metabolic equivalents.

One MET represents approximately the oxygen cost of resting metabolism and is conventionally estimated as: 1 MET ≈ 3.5 mL O₂/kg/min

Therefore, someone capable of approximately 10 METs has an estimated oxygen consumption around: 35 mL/kg/min.

This is one reason MET capacity frequently appears in treadmill testing and epidemiological research.

And it makes the research easier to appreciate.

The 2024 review by Lang et al. found that each 1-MET higher level of CRF was associated with substantially lower all-cause mortality risk across the underlying evidence (Lang et al., 2024).

More importantly, Kokkinos et al. (2023) showed that changes in fitness matter.  In their cohort, changes of at least 1 MET were associated with inverse and proportional changes in mortality risk (Kokkinos et al., 2023).

That's powerful because it transforms fitness from a label-

"I'm in good shape."

-into something that can be monitored longitudinally.

Executive Action Plan

You do not need to redesign your entire training program tomorrow. Start by treating aerobic capacity like any other important performance variable:

Coach's Challenge

This month, I want you to answer one question:

How big is your aerobic engine?

Not:

"Do I do cardio?"

Not:

"Do I get 10,000 steps?"

Not:

"Can I run a few miles?"

Ask instead:

What objective evidence do I have of my current cardiorespiratory fitness?

If the answer is "I don't know," that isn't a failure.

It's simply an unmeasured performance variable.

Establish a baseline.

Then spend the next several months improving it intelligently.

Because the ultimate goal isn't a better VO₂ max score.

The goal is what that capacity allows you to do.

Travel without physical limitation.

Walk all day exploring a new city.

Climb stairs without thinking about them.

Hike with your family.

Ski.

Golf.

Play tennis.

Train hard.

Recover faster.

Handle demanding days.

Maintain independence.

And continue doing those things well into the decades ahead.

Key Takeaways

VO₂ max is more than an endurance metric. It reflects the integrated ability of the cardiovascular, respiratory, circulatory, and muscular systems to deliver and utilize oxygen.

Cardiorespiratory fitness is strongly associated with longevity and health. Large cohort studies and meta-analyses consistently demonstrate an inverse, graded relationship between CRF and mortality risk (Kodama et al., 2009; Lang et al., 2024; Mandsager et al., 2018).

Fitness remains important across the lifespan. A study of more than 750,000 adults found the relationship between higher CRF and lower mortality across age, sex, and racial groups, including older adults (Kokkinos et al., 2022).

Fitness is modifiable. Changes in cardiorespiratory fitness over time are associated with corresponding changes in risk (Kokkinos et al., 2023).

Aerobic capacity declines with aging. Maintaining fitness therefore becomes increasingly important if the goal is preserving physiological reserve and independence (Fleg et al., 2005).

Both aerobic base training and higher-intensity training have value. Continuous endurance exercise and interval training can improve VO₂ max, with the appropriate combination depending on the individual (Milanović et al., 2015; Weston et al., 2014).

And perhaps most importantly:

The goal isn't to train like an endurance athlete. The goal is to build enough physiological capacity that the life you want to live never feels like an endurance event.