Fitness Fallacies: VO2 Max, HIIT, and Wearables
Frameworks with Carl Hardwick | CoachRx Podcast Network
A fitness metric can be useful without becoming the purpose of your training. Trouble starts when a complicated idea gets packaged as the answer to a long, healthy life, better fitness, or personal health.
In a conversation between Carl Hardwick and James Fitzgerald, three popular claims get a hard look: VO2 max as a longevity predictor, high-intensity interval training as the most efficient path to fitness, and continuous glucose monitors for healthy people. The bigger issue is the same in each case: giving away your judgment to a score, a trend, or a device.
Why simple fitness answers are so persuasive
"VO2 max is the number one predictor of longevity" sounds convincing because it sounds precise. It gives people a clear target, a number to improve, and the feeling that they have found a shortcut through a complicated subject.
Fitzgerald rejects that framing outright. His concern is not that aerobic work has no place in training. Rather, he argues that presenting any one metric as the answer turns a complicated human question into a sales-friendly promise.
Fitness language often helps this happen. Terms such as VO2 max, biomarkers, dose response, and metabolic health can make a message sound authoritative before anyone has stopped to ask what the claim means in daily life. A performance diagnostic can be useful in a particular setting, yet it does not automatically become a universal prescription.
A number can describe part of a person without describing the life that person is living.
The urge for certainty also plays a role. If a doctor, professor, influencer, or coach appears to have a single answer, people can hand over responsibility for thinking through their own goals. That is easier than confronting questions about health, family, stress, physical capability, and how they want to spend their time.
VO2 Max and Longevity Are Bigger Than One Score
VO2 max generally refers to the maximum amount of oxygen the body can use during intense exercise. It has a place in exercise testing and performance conversations. However, Fitzgerald's objection is to treating a higher number as the primary goal of life.
Someone who hears that VO2 max predicts longevity may decide they need to push their score from 42 to 62 as fast as possible. In the process, they may overlook whether the training suits their body, responsibilities, interests, or ability to sustain it for years.
A better aim is capable expression
Fitzgerald offers a different standard: pursue the most capable expression of yourself, with strong mental acuity and awareness, for as long as possible. That leaves room for a 16-year-old and a 72-year-old to train seriously without pretending their goals or capacities should look alike.
This view also changes the meaning of longevity. More years are not automatically better if those years are consumed by anxiety, endless optimization, and dependence on expensive interventions. A long life matters, but so do time with family, community, meaningful challenges, and the ability to participate in your own life.
Daily physical challenges can be part of that expression. Walking, lifting, playing, carrying, moving outside, and practicing a sport may all have value without needing to justify themselves through a single score.
Coaches need to ask why
When a client says, "I need to increase my VO2 max," the first response should not always be a new interval plan. A coach can ask why that number matters to the client, where the belief came from, and what they expect it to change.
Those questions may reveal that the client is chasing an attainable six-month goal because they have not considered what will keep them active for the next 20 years. That conversation requires patience, but it moves coaching toward responsibility rather than trend-following.
Foundational habits remain useful places to start: regular sunlight, water, consistent sleep, eating with attention, and physical activity that fits real life. Coaches looking for practical materials can find them in the OPEX free coaching resources.
The Problem With Efficiency-First HIIT
The second claim is that high-intensity interval training, often shortened to HIIT or HIT, is the most efficient way to build fitness. Fitzgerald pushes back on the word "efficient" because it often means "fastest possible results with the least time," not sustainable physical development.
Hard intervals create a response. After a demanding workout, the body works to recover and return toward homeostasis. That is the basic idea behind a dose response: a stressor produces a physiological reaction.
The issue arises when people start chasing the reaction itself. Exhaustion, sweat, sore muscles, elevated heart rate, and lying on the floor after a session can become proof that the workout "worked." Social media has made this easier to celebrate. Visible suffering gets attention, and the intensity becomes part of a person's identity.
A hard workout is not a complete training philosophy
Fitzgerald acknowledges that hard intervals create a dose response. Still, that does not prove they are the best choice for every person, every day, or every goal. Training that repeatedly leaves someone depleted can become hard to maintain. In his words, unsustainable work can lead to unsustainable behaviors.
Walking for long periods, building a base of easier aerobic work, and doing physical activity you can repeat for years may look less dramatic online. Yet these choices can better support a life that includes work, family, sleep, and other responsibilities.
Language matters here, too. "High intensity" is broad enough to mean almost anything. That vagueness allows a training method to be presented as universally useful while avoiding a clear discussion of dosage, recovery, context, and individual needs.
Wearables Can Measure Data and Still Reduce Awareness
The third claim is that everyone should wear a continuous glucose monitor, even healthy people. Fitzgerald sees this as part of a wider problem with trackers, wearables, and devices that promise to tell people how they feel.
Continuous glucose monitors may have medical uses, and their role in clinical care is outside this discussion. The concern here is the casual push for healthy people to monitor every fluctuation and make food or activity choices based on a device rather than their own experience.
Fitzgerald describes having used several wearables, including an Oura Ring and a WHOOP band, before realizing that he had begun outsourcing his internal judgment. He argues that people can learn a great deal by paying attention to the connection between their actions and their energy, mood, sleep, and training readiness.
Physical experience teaches responsibility
You learn your limits through experience. Over time, a person who trains attentively can develop a sense of what they can safely lift, when they need rest, which meals leave them energized, and which habits make them feel worse.
A device may provide data, but it cannot replace that process. The risk is greater when young athletes adopt trackers before they have had time to build confidence in their own observations. Instead of learning, "I slept poorly and feel flat today," they may wait for a readiness score to tell them what they already know.
Carl Hardwick connects this concern to a simple phrase: be more human. Technology can support a decision, but it should not remove a person's ability to reflect, notice patterns, and make choices. Coaches who want to build more thoughtful client conversations can explore the OPEX Method Mentorship.
Start With Intentions, Not Fitness Trends
Fitness will keep producing new metrics, methods, and devices. That makes it easy to spend years chasing the next interesting thing. Fitzgerald's answer is to return to intention.
Before adding a metric, hard interval, or wearable, ask what it is for. Does it support your ability to live, work, relate to others, and take part in physical challenges? Or does it mainly give you another number to manage?
Coaches can help clients stay with those questions long enough for honest answers to emerge. That kind of work asks more than writing a program, but it can help people build a relationship with exercise that does not depend on whatever trend dominates next month. The CoachRx Podcast Network offers more coaching conversations centered on that broader view.
Fitness Should Build More Personal Freedom
VO2 max, HIIT, glucose data, and wearables can all be discussed without turning them into universal commandments. The problem begins when a tool becomes the authority and personal awareness fades into the background.
The strongest fitness goal may be simple: build a life where you can move capably, think clearly, and make informed decisions about your own body. Your intentions matter more than the next score you are told to chase.
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