When most people think about getting fit or improving their health, they tend to focus on external markers—weight, appearance, or how sore they feel after a workout. But some of the most meaningful indicators of long-term health are happening under the surface, especially in how your body handles oxygen and energy.
Two key metrics—VO₂ max and resting metabolic rate (RMR)—give us insight into how efficiently your body functions, how resilient it is under stress, and, importantly, how well you’re aging biologically. These aren’t just numbers for elite athletes. They’re valuable for anyone who wants to stay strong, mobile, and independent as they age.
Let’s break down what these terms mean, why they matter, and how we use them at Raise the Bar Training Studio in Old Town Scottsdale to help clients train smarter for both performance and longevity.
What Is VO₂ Max?
VO₂ max stands for maximal oxygen uptake. It’s the maximum amount of oxygen your body can take in, transport, and use during intense physical activity. The higher your VO₂ max, the more efficiently your body delivers oxygen to your muscles—and the better your cardiovascular system performs under stress.
Think of VO₂ max as a ceiling for your aerobic fitness. The more oxygen your body can use, the more sustainable power or speed you can generate. That applies whether you’re running a race, hiking a mountain, or just playing with your kids.
Why It Matters for Longevity
VO₂ max isn’t just a performance metric—it’s one of the strongest independent predictors of all-cause mortality. A 2018 study in JAMA Network Open followed over 120,000 adults and found that individuals with elite-level cardiorespiratory fitness had the lowest risk of death from any cause. The higher the VO₂ max, the lower the risk—even more so than for people who quit smoking or managed high blood pressure.
Other research shows VO₂ max naturally declines with age, dropping about 10% per decade after your 30s—unless you actively train to maintain it. That makes it not just a snapshot of current fitness, but a powerful marker of your biological age: how well your body is functioning relative to your chronological age.
What Is RMR?
Your Resting Metabolic Rate (RMR) is the number of calories your body burns at rest to support basic functions like breathing, circulation, digestion, and cellular repair. It accounts for the largest portion of your daily energy expenditure, often around 60–75% depending on your activity level.
RMR is often confused with basal metabolic rate (BMR), but they’re similar. RMR is a slightly more practical measure since it allows for a more real-world testing setup and includes small amounts of energy used during minimal activity (like sitting quietly).
Why It Matters for Body Composition and Health
Knowing your RMR helps you set a realistic and individualized calorie intake. Most online calculators use generalized formulas based on age, sex, height, and weight—but they don’t take into account factors like lean muscle mass, hormonal adaptation, or long-term stress. This is why two people with the same stats can have very different metabolic rates.
When people chronically under-eat or over-exercise, RMR can actually downregulate—meaning your body adapts by slowing down energy output to conserve resources. This is one reason many dieters hit plateaus or feel exhausted despite “doing everything right.” By measuring RMR, we can spot these adaptations early and adjust food or training to get things back on track.
The Role of Heart Rate Zones in Smart Training
One of the biggest benefits of VO₂ max testing is the ability to define your heart rate training zones—based on your actual physiology rather than estimates.
Most wearables guess your zones using age-predicted max heart rate formulas (like 220 – age). That’s fine for general use, but it can be way off—especially if you’re outside the norm.
Here’s a simplified breakdown of the zones we calculate from your test:
- Zone 1: Very light. Good for recovery and active movement.
- Zone 2: Aerobic base training. This is the longevity zone—it improves fat metabolism, insulin sensitivity, mitochondrial function, and builds your cardiovascular foundation.
- Zone 3: Moderate to hard. Where many people default to, but it’s often not targeted enough to drive specific adaptations.
- Zone 4–5: Threshold and VO₂ max zones. These are short bursts of high-intensity work that push your limits and improve top-end performance.
Zone 2 is particularly important for longevity. It strengthens your heart without stressing your nervous system, helps you use fat for fuel more efficiently, and increases your aerobic capacity over time. But most people don’t spend enough time here—either because they go too hard, or don’t know what heart rate range actually qualifies.
How We Use This Data at Raise the Bar
At our studio, we use the VO2Master to test both VO₂ max and RMR in a comfortable, gym-based setting. No labs. No cords hanging off your face. Just real-time data you can use immediately.
Here’s what you walk away with after a full assessment:
- Your VO₂ max score compared to age and sex norms
- Your estimated biological fitness age
- Your RMR, so you know how many calories your body actually burns at rest
- Your personal heart rate training zones, so you can dial in workouts for fat loss, endurance, or performance
- A clearer picture of what’s working (and what’s not) in your training and nutrition
Whether your goal is to live longer, move better, train more efficiently, or just understand your body more deeply—this type of testing takes out the guesswork.
