How to understand our fitness calculator

During the last few weeks, our fitness calculator has been spread all over the world, thanks to the NY Times blog post. We are happy to announce that the calculator now inow is available as an app for smartphones (currently only for Apple devices). It is called VO2cal and you can download it for free in AppStore.

The great media coverage has resulted in tons of questions from people all over the world, which we of course appreciate – nothing is better than transforming our research from statistics to useful tools for everyone, and, hopefully, promote a healthy lifestyle. However, it is not possible to answer individually, and in this blog post, we will explain the background of the calculator and answer frequently asked questions. Check out the FAQ section at our website as well.

The calculator uses maximal oxygen uptake as an indicator for fitness, and very many simply ask what this means. Briefly, maximal oxygen uptake is a measure involving several factors:

  • how well the lungs are breathing
  • how efficiently oxygen is transported into the blood
  • how well the heart is pumping blood to the working muscles
  • how well the blood vessels are transporting blood
  • how good the muscles are to receive and utilize oxygen

…and this value has been shown to be the single best predictor of current and future cardiovascular health. Usually, the test is performed by running on a treadmill with a mask, through which the ventilation of oxygen and carbondioxide during high intensive exercise is measured. Much easier to perform at a calculator, isn’t it?

The calculator requires information such as gender, age, waistline measure and resting heart rate, as well as frequency, duration and intensity of ecercise. In a few seconds you get your estimated maximal oxygen uptake, and your fitness age – meaning, how old are you according to your fitness level, compared to other healthy subjects?

The basis and method behind the fitness calculator are described in details in the articles of Aspenes et al. (2011) and Nes et al. (2011), both former PhD candidates in Cardiac Exercise Research Group. Through participation in the Nord-Trøndelag Health Study (HUNT), more than 4600 healthy Norwegians between 20 and 90 years were tested on several parameters, among other maximal oxygen uptake.

The researchers discovered that the mean maximal oxygen uptake in women and men were 35 and 44 mL/kg/min, respectively. Further, they found a ~7% decline in maximal oxygen uptake with every 10 year raise in age in both genders. Women and men below the gender-specific mean were 4 to 8 times more likely to have a combination of more than three conventional cardiovascular risk factors (for instance, metabolic syndrome) compared to the most fit quartile of subjects. The researchers also observed that maximal oxygen uptake may represent a continuum from health to disease, and that a general 5 mL/kg/min lower maximal oxygen consumption was associated with ~56% higher odds of having the metabolic syndrome. This HUNT material is the historically largest and most robust of its kind with directly measured maximal oxygen uptake and more than 4600 subjects, and constitutes a stable reference for the fitness calculator.

oxygen uptakeHow can I calculate my maximal oxygen uptake in liters?
If your body weight is 50 kg and you have a maximal oxygen uptake of 50 ml/kg/min you should multiply the two and convert VO2max from ml/min to L/min (i.e. 50kg x 50 ml/kg/min = 2500 ml/min =2.5 liters/min.)

In your test, is walking at a brisk pace considered exercising?

Yes, walking is considered exercise.

The questions you ask don’t accurately reflect my exercise or lifestyle.
We completely understand someone’s concern about this. However, if we are about to test 5000 people we have to be partly general in how to ask the questions. We have shown that it is reasonably accurate in more than 5000 persons, so in general, the questions can be considered reliable. We recommend to answer as best you can to describe a normal week for you – and we are confident that this will give an accurate estimate.

How can I improve my maximal oxygen uptake effectively?
We have made a 7-weeks exercise program that is presented at our homepage, where you can also watch a video about 4×4 intervals.

Why do you not use Body Mass Index (BMI) in the calculator?
Whether we used BMI or waist did not really matter for the outcome (we made several alternative calculators) but the chosen one was slightly better. Further, it has been shown that waist is a much better predictor of future cardiovascular disease risk compared to BMI in several large studies.

Why do you not include fitness ages above 75 and below 20?
There were too few subjects above the age of 75 to make a reference material that made sende for those older than 80 years of age – and we did not test individuals younger than 20 years of age.

Ulrik Wisløff, professor and leader of Cardiac Exercise Research Group.

This entry was posted in 4x4, Exercise, Fitness, In English, Media, Research and tagged , , by CERG. Bookmark the permalink.

About CERG

The Cardiac Exercise Research Group (CERG) at the Norwegian University of Science and Technology (NTNU) seeks to identify the key mechanisms underlying the beneficial effects of physical on cardiac health in the context of disease prevention and treatment. Named the K.G. Jebsen Center for Exercise in Medicine under Professor Ulrik Wisløff's leadership in 2011, CERG uses both top-down and bottom-up approaches to combat lifestyle-related disease.

9 thoughts on “How to understand our fitness calculator

  1. This was an excellent research. I never had such a well planned research on line before.
    Congratulations to all the experts involved in preparation of it.

  2. For a result of “less than 20 years old” your website calculator shows “-20”. Multiple friends read that as “negative 20” and thought your calculator was broken.

  3. Hey guys,

    I think you have to think about the alcohol question once again. If someone drinks 6 bottles of low alcohol beer in one evening and the other person drinks 1 regular beer, this could be interpreted in a wrong way. As you assume that drinking alcohol is always the same, regardless the amount of alcohol consumed, this could lead to a wrong view. Instead of asking “how often do you drink alcohol?” you could better go for a question like “How often do you drink alcohol and where would you you rate yourself on a scale between 0-10 (low amount of alcohol – high amount of alcohol)?” or something in this way.

    As for this topic I was also wondering about the setup regarding the meals. The question setup doesn’t fit my daily lunches because you leave bread/meat/milk products out.

    I liked the design very much and the User Interface leads my through the question in a nice looking and easy to handle way. Thumbs up for the designer/creator.

  4. Thank you for doing so much work and contributing it freely. Unfortunately, your “fitness-numbers” page doesn’t explain the results. I got a -25 for my VO2 max and a link to a table saying 38 was the mean VO2 max for a woman my age. So how can I have a negative number and what on earth would that mean? Looking at the above numbers I believe I’ve figured out that it means something bad, possibly 25% less than average. I recommend writing a clearer explanation of what the numbers and the plus and negative signs mean.

  5. Awesome! I like your starting words to keep the visitor stay and read your full blog post. Anyhow the overall post is really informative and contains tons of knowledgeable factors. Thank u so much for sharing this post.I wanna share some information about medicine manufacturers for you.Please visit:
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