A Cornerstone of Health and Fitness: Breaking down the differences in V02 & Resting Metabolic Rate (RMR)

A Cornerstone of Health and Fitness: Breaking down the differences in V02 & Resting Metabolic Rate (RMR)

In today’s world that continues to rapidly grow in many areas, the fitness industry has been soaring. More individuals are seeking not only physical aesthetics but finding what is optimal for their health and performance. But when it comes to understanding the aspects of one's health it can become complicated, so I am here to break down the key metrics of what maximal oxygen uptake (VO2) and resting metabolic rate (RMR) can do for you to improve your health and fitness. Whether you are a trained athlete or beginning to start your fitness journey, understanding what VO2 max and RMR is can help pave the way towards a healthier and more energized life. 

What is VO2 Max?

The professionals at WebMd identify VO2 max, also known as maximal oxygen uptake. It is a measurement of the maximum volume (V) of oxygen (O2) that your body is able to use during a maximal effort exercise. According to leading experts in exercise physiology, including Peter Attia & Mike Joyner, MD it is one of the most accurate indicators of an individual's cardiovascular fitness and aerobic endurance. It helps determine the efficiency of your heart, lungs, and muscles when consuming and utilizing oxygen. When determining what your VO2 max is, it is important to take your age, gender, fitness levels, genetics, and body composition into consideration to get the most accurate results. 

VO2 max offers an objective view of your overall health and the effectiveness of your training routines. Understanding your VO2 max and what it means can help tailor your workouts to get the best outcomes for health and fitness. It can reveal how effectively your heart is able to pump blood to and through your muscle efficiently. 

As you're working out you begin to notice your breath is becoming faster and you are breaking a sweat. Have you ever wondered why this happens? Well, when you make these efforts outside your body's comfort zone it resorts to creating an energy known as Adenosine Triphosphate (ATP). ATP is produced as you breathe in oxygen, it powers a metabolic reaction within your muscle cells. The more oxygen you take in the more ATP you produce which can help increase your energy levels to continue your workout. 

What is RMR?

Resting Metabolic Rate (RMR) is the number of calories that your body burns while at rest.  It represents the minimum amount of energy your body requires for the simple task of living, such as breathing, circulating blood, maintaining body temperature, and cellular processes like repairing muscle tissue. Your RMR accounts for about 60%-70% of your total daily energy expenditure, even for people with low activity levels.  It can help individuals understand how to manage their body weight by giving a specific number of calories they should consume to meet their goals. 

Your metabolism encompasses the reactions that occur within each cell that provide energy for daily living, anywhere from breathing and circulating blood to chewing your food and walking. The food we consume on a daily basis plays a major role in metabolism. It provides nutrients, vitamins, and minerals that our body relies to absorb and convert into immediate energy or stored in your body for later use. 

Understanding your personal resting metabolic rate helps determine how many calories you burn throughout the day and how many calories you should consume to achieve your goals. Your RMR can be tailored to your goals, whether it is to lose, gain or maintain weight. Calculating your RMR can provide insight to your daily energy needs which can be influenced by your age, gender, race, disease, and activity level.  

The Relationship

VO2 max and RMR are complementary measures of the different aspects of an individual's metabolic function and energy utilization. Serving as a baseline of metabolic functioning, considering these as a pair is crucial. Both measures provide an understanding of overall fitness, energy expenditure, and health. 

Individuals with a higher VO2 max often have an elevated RMR. Meaning that your body will burn more calories throughout the day when the volume of oxygen your body utilizes during exercise is higher. Exercising regularly can boost your VO2 max and can not only enhance your cardiovascular health but also the amount of muscle mass and metabolic activity. The dual effect of these processes can elevate your RMR over time especially when complimented by strength training that helps to increase lean muscle mass. 

Both can also work together for effective weight management strategies. Understanding the synchrony between VO2 and RMR can provide individuals with insights to the most effective ways to reach their goals. While VO2, as we learned, reflects exercise capacity, RMR displays the calorie requirements and baseline metabolism. Together it allows us to tailor the dietary choices we make and the exercise we choose to participate in which works to support achieving and maintaining a healthy weight. 

  Integrating these metrics into our overall health, can open new pathways to breakdown the essential parts we must understand.  We are able to gain a comprehensive understanding of our fitness levels, energy expenditure, and metabolic efficiency that can be customized for each individual. Whether you are looking to improve athletic performance, overall health or manage your weight effectively, taking advantage of both VO2 max and RMR will help guide you towards your needs for a healthier and sustainable lifestyle. 

How are the measurements administered?

A VO2 max test is considered the gold standard of measuring cardiovascular fitness. It involved a protocol where an individual undergoes progressively intense exercise while closely monitoring oxygen consumption and heart rate. Typically, the test starts with a warm up and transitions into more difficult stages throughout. It can be tested by running or cycling. A mask is placed over the individual's mouth which is connected to the equipment and measures the amount of oxygen consumed and their heart rate response. 

The most common way of measuring RMR is through an indirect calorimetry, which involves measuring the amount of oxygen consumed and carbon dioxide produced by the body. During the test, the individual rests comfortably in a reclining position while breathing into a mask that is connected to the equipment. The equipment analyzes the amount of inhaled and exhaled air, using it to calculate how much oxygen is consumed and carbon dioxide is produced. From the measurements, the RMR is estimated based on the equations used to determine oxygen consumption and energy consumption. 

Comparing test results?

I think the most difficult part of VO2 max and RMR is finding a solution to get the most accurate results. There are many solutions and techniques to measuring heart rate and metabolism, but what can we trust for the most accurate results? 

I am sure we are all familiar with the fitness watches and each of the health measurements it takes throughout the day. While they are convenient to use, it gives a broad estimate of what your health actually is. Measurements are being taken from the wrist which is one of the farthest parts of your body from your major organs. Which is why these watches use algorithms to estimate these measurements. 

I am a culprit of using my watch to measure my health and have trusted it for years. I have recorded most of my workouts on my Apple watch  (video tracking health and fitness on the Apple Watch) for years now and have utilized the measurements it has taken for me but haven’t seen the improvements I have been aiming for. 

I recently had both my VO2 and RMR tested in a lab setting and saw significant differences in my results when compared to my watch. According to my Apple Watch, my most recent VO2 max is 34.3 mL/kg/min, which is considered below average on their spectrum. Knowing that I am regularly doing cardio, this surprised me. My RMR measurement from the watch indicated that while resting and doing low level activities I was burning about 1,500 kcal.  After getting my VO2 max and RMR test done in a fitness facility using KORR Cardio coach, my VO2 max was 40.6 mL/kg/min. Which was a huge difference from being below average to cardio coach considering my VO2 max excellent. While my RMR was significantly higher according to the cardio coach being at about 1,800 kcal. 

While there are many different solutions to these measurements, knowing which ones are more accurate than others can help individuals determine what's write for their health. Seeing these differences in my own results helped me understand why I haven’t been seeing the results I am looking for. Knowing that I have a higher VO2 max and RMR than I originally thought, I am able to tailor my training programs and eating habits to meet my goals. It is very important that people understand what the most accurate measurements are when it comes to health because it can greatly impact their lifestyles. 

Now that you have a brief overview of what VO2 max and RMR are we can say that they are crucial indicators of your overall health and fitness. Understanding what these measurements do, you can seamlessly incorporate the assessments into your health and fitness routines. These measures offer a comprehensive approach to metabolism efficiency, energy expenditure, and your overall fitness levels. Whether you are training for athletic performance, weight management, or general health improvement, utilizing these tests can help align your health decisions with your specific goals. 


VO2 max: How To Measure and Improve It (clevelandclinic.org)

hrpfam5_table-8-9-updated.pdf (acsm.org)

RMR: What Is Resting Metabolic Rate? (verywellfit.com)


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