Fitness calculator – CERG – NTNU

In 2007 and 2008, several thousand Norwegians tested their VO2max on a treadmill in The HUNT Fitness Study. They also answered several questions and had a complete health check-up as part of the third HUNT study (HUNT3).

Therefore, we could establish the most important factors for fitness among healthy women and men. These facors – namely age, waist circumference or body mass index (BMI), leisure-time physical activity and resting heart rate – are those included in the algoritm that constitutes our Fitness Calculator.

Read the full research article:
Estimating V˙O2peak from a Nonexercise Prediction Model: The HUNT Study, Norway

Later, we showed that The Fitness Calculator is even more accurate in older adults if we add simple measures of lung function to the model. However, the current calculator is accurate enough for all age groups, and we have not included the lung function measurements in the formula. The study was based on our large Generation 100 study, and included direct measurements of VO2max and lung function in almost 1500 older adults.

Read the full research article:
Lung function parameters improve prediction of VO2peak in an elderly population: The Generation 100 study

After we made The Fitness Calculator, we showed that the estimated fitness number is of great importance for how long you can expect to live. That’s why we now recommend every physician to use the calculator to identify patients with high risk of lifestyle diseases and early death. We still use The Fitness Calculator in much of our research, and each study makes us even more convinced that the calculator is a very useful tool to prevent lifestyle diseases. 

Predicts early death

By use of the Fitness Calculator, we estimated fitness in 37,000 healthy individuals who participated in the HUNT1 study in the 1980s. We then followed them for 24 years and looked at health outcomes. The risk of dying from cardiovascular disease was 21% lower for each increase of 3.5 mL/kg/min, or 1 MET. This associations persisted after adjusting the analysis for confounding factors. The risk of dying from all causes during follow-up was also gradually reduced with better fitness.

Read the full research article:
A Simple Nonexercise Model of Cardiorespiratory Fitness Predicts Long-Term Mortality

Moreover, the number you get from The Fitness Calculator seems to be all you really need to estimate the risk of cardiovascular disease and premature death in presumably healthy individuals. We studied this in almost 40,000 participants from the HUNT study who were followed for up to 17 years. The calculator estimated the risk about just as good on its own as when traditional risk factors for cardiovascular disease are included in the model.

Read the full research article:
Prediction of Cardiovascular Mortality by Estimated Cardiorespiratory Fitness Independent of Traditional Risk Factors: The HUNT Study

The Fitness Calculator doesn’t only predict risk of early death. It also predicts a heart attack in middle-aged and older individuals. We followed 26,000 healthy women and men for 13 years, and for each 1 MET increased fitness, the risk of an acute heart attack was 11% lower in women and 3% lower in men.

Read the full research article:
Cardiorespiratory FItness and the Risk of First Acute Myocardial Infarction: The HUNT study

We have also published results that link better estimated fitness to lower risk of atrial fibrillation. In women, each increase of 1 MET was associated with 16% reduced risk, whereas the corresponding risk reduction was 5% in men. Even increasing fitness over time seems to be beneficial to reduce the risk of atrial fibrillation. The results are based on data from 40,000 women and men who participated in HUNT3, of which 22,000 also had taken part in HUNT2 eleven years earlier.

Read the full research article:
Estimated Cardiorespiratory Fitness and Risk of Atrial Fibrillation: The HUNT Study

We have also confirmed that the Fitness Calculator estimates fitness accurately in persons with established atrial fibrillation. During the HUNT4 Fitness Study, 652 men and women with atrial fibrillation performed a maximum oxygen uptake test, and we used this sample to validate the Fitness Calculator in this group of patients. In men, the calculator overestimated true fitness by on average 2.5 fitness numbers, whereas the difference was only 0.2 in women.

The main results of that research paper show that persons with established atrial fibrillation are at lower risk of early death and cardiovascular events the higher they score on the Fitness Calculator. The 25% with the highest age-ajusted fitness had 30–40% lower risk than those with the lowest estimated fitness. For each increase of 1MET, the health risk decreased by 12–15%. The study includes a total of 1117 men and women with confirmed atrial fibrillation, and we followed them for up to nine years.

Read the full research article:
Physical activity, cardiorespiratory fitness, and cardiovascular outcomes in individuals with atrial fibrillation: the HUNT study

Medium and high estimated fitness also predicts lower likelihood of having depression, as well as lower risk of getting depressed. The third of 26,000 middle-aged and older HUNT2 participants with the lowest fitness levels had 26% higher odds of having depression compared to the fittest third. Among 14,000 individuals who also participated in HUNT3 eleven years later, the risk of getting depression between the two surveys was reduced with around 20% in those with medium or high estimated fitness at HUNT2.

Read the full research article:
Cross-sectional and longitudinal association of non-exercise estimated cardiorespiratory fitness with depression and anxiety in the general population: The HUNT study

Moreover, we have shown that persons who maintain high estimated fitness and report low symptoms of depression over time have lower risk of dying during follow-up than those with low fitness and more depressive symptoms. The study is based on information from more than 15,000 middle-aged women and men from the HUNT2 and HUNT3 studies.

Read the full research article:
Long-term Changes in Depressive Symptoms and Estimated Cardiorespiratory Fitness and Risk of All-Cause Mortality: The Nord-Trøndelag Health Study

Those who maintain high fitness and those who improve their fitness have a 40-50% reduced risk of getting dementia compared to those who have poor fitness over time. Also, high fitness is linked to significantly reduced risk of dying from or with dementia. We have followed more than 30,000 men and women for up to 30 years, and estimated their fitness in both the 1980s and 1990s. The risk of dementia was 16% lower for every 1 MET age-adjusted increase in fitness between the two surveys.

Read the full research article:
Temporal changes in cardiorespiratory fitness and risk of dementia incidence and mortality: a population-based prospective cohort study

Improved estimated fitness over time is also linked to higher brain volumes in middle-aged persons. 751 men and women aged between 50 and 67 years had their brains scanned as part of the HUNT3 study. The same persons also participated in the HUNT2 study eleven years earlier, and those who maintained high fitness or improved from low to high between the two surveys had bigger brains than those who stayed unfit.

Read the full research article:
Associations of Changes in Cardiorespiratory Fitness and Symptoms of Anxiety and Depression With Brain Volumes: The HUNT Study

Another study show that individuals with low estimated fitness have several-fold increased likelihood of non-alcoholic fatty liver disease. We found that the 20% with the lowest fitness had 17 times the odds compared to the 40 % with the highest fitness, even among individuals who sat less than four hours a day. Furthermore, among the 36 % who had non-alcoholic fatty liver disease in our cohort, the risk of dying within the next nine years was 50 % higher in those with low fitness according to The Fitness Calculator.

Read the full research article:
Non-alcoholic fatty liver disease: prevalence and all-cause mortality according to sedentary behaviour and cardiorespiratory fitness. The HUNT Study