VO2 Max Is Not Just for Athletes. It Is One of the Best Predictors of How Long You Will Live.

By Dr. Daniel O'Loughlin, DO, MPH, CAQSM | Founder, Keystone Longevity

Most people encounter the term VO2 max in the context of athletic performance. Runners track it. Cyclists obsess over it. Endurance coaches use it to structure training programs.

That framing has done a disservice to the general population, because VO2 max is not primarily a performance metric. It is one of the strongest predictors of long-term health and longevity we have access to.

What VO2 Max Actually Measures

VO2 max is the maximum amount of oxygen your body can take in, transport, and use during intense physical effort. It reflects how efficiently your heart, lungs, blood vessels, and muscle cells work together as an integrated system.

When that system is functioning well, your body can sustain demanding activity, recover efficiently, and adapt to physiological stress. When it is not, the downstream effects extend well beyond exercise performance.

The research on this is consistent and substantial. Higher cardiorespiratory fitness is associated with significantly lower risk of death from cardiovascular disease, metabolic disease, and other major causes. The effect size is not small. Low fitness carries a mortality risk that, in some studies, is comparable to or exceeds that of smoking or diabetes.

That is worth sitting with. A number your doctor rarely measures is one of the most consequential indicators of how well your body is aging.

The Part Most People Get Wrong

The common assumption is that VO2 max declines with age and there is not much to be done about it. That assumption is only partially correct.

VO2 max does decline with age. But the rate of that decline largely depends on how much you demand of your cardiovascular system over time. In people who train consistently, the decline is substantially slower. In those who are sedentary, it accelerates.

Research also shows that VO2 max is trainable at every stage of life. It improves with the right stimulus, whether you are 35 or 65. The decline is not a fixed sentence. It largely reflects accumulated lifestyle inputs.

This is exactly the framework we apply to longevity more broadly at Keystone. The conditions that limit your function in your 60s, 70s, and beyond are being shaped right now by the choices you make consistently. Cardiorespiratory fitness is one of the clearest examples of that principle.

How Cardiorespiratory Fitness Is Built

Building and maintaining VO2 max does not require extreme training. It requires the right kind of training applied consistently over time. In sports medicine, we generally focus on two primary inputs:

•      Zone 2 training. This refers to sustained aerobic effort at a moderate intensity, typically described as a pace where you can still hold a conversation without difficulty. It feels easy, which is why most people skip it. But Zone 2 work builds the aerobic base that everything else depends on. It improves mitochondrial density, fat oxidation, and cardiac output. For most adults looking to protect long-term health, this is where most effort should go.

•      High-intensity intervals. Brief, hard efforts near your maximum capacity push the upper limit of your aerobic system. You do not need a large volume of this to see benefit. A small, well-placed amount of interval work, layered on top of a solid aerobic base, is sufficient for most people who are not competitive athletes.

The third element matters most and is the hardest to market: consistency over time. You don't build VO2 max in a few weeks and maintain it without effort. You build it over months and maintain it over years through regular aerobic demand on the cardiovascular system.

This is not a protocol for athletes. It is a protocol for anyone who wants a heart and lungs capable of carrying them through the second half of life with capacity to spare.

How This Connects to the Five Pillars

Exercise is one of the five pillars we build Keystone Longevity around, and cardiorespiratory fitness is one of its most important outputs. But it does not exist in isolation.

Sleep supports recovery and the hormonal environment that enables physical adaptation. Nutrition provides the fuel and raw materials for cardiovascular function. Hydration directly affects blood volume, oxygen delivery, and exercise capacity. Social connection, which may seem unrelated, is associated with sustained motivation and adherence to health behaviors over time.

Practically, this means improving VO2 max is not just a matter of adding exercise. It means supporting the full system that makes physical adaptation possible. The pillars reinforce each other, and cardiorespiratory fitness is one of the clearest places where that becomes visible.

A Note on Supplementation

Supplements do not build VO2 max. Training builds VO2 max. That distinction matters, and I will not suggest otherwise.

Supplementation can support the underlying systems that make training productive and recovery efficient. Omega-3 fatty acids support cardiovascular function and help manage the inflammatory load that comes with consistent training. Electrolytes maintain the hydration status that exercise capacity depends on. Creatine supports cellular energy production and has shown benefit for both muscular and cognitive endurance.

These are supportive tools. They work when the training and lifestyle inputs are in place. They are not a substitute for the aerobic work itself.

The Broader Point

VO2 max matters because it directly measures how efficiently your body uses one of life's most fundamental inputs. When that system is strong, everything downstream benefits. When you neglect it, the consequences accumulate slowly and then become difficult to reverse.

You do not need to be training for a race to take this seriously. You need a cardiovascular system that supports your independence, cognitive function, and quality of life for decades. You build that system now, through consistent effort over time.

That is the whole point of the approach we take at Keystone. Not extremes. Not shortcuts. Just the right inputs, consistently applied, compounding in your favor.

-- Dr. Daniel O'Loughlin, DO, MPH, CAQSM

Founder, Keystone Longevity