The Impact of Aerobic Fitness of Lifespan

Recently, the Journal of the American College of Cardiology (JACC) published the findings of a 20-year study  looking at how various levels of aerobic fitness impacted lifespan. Without exaggeration, I find the results to be staggering! The authors studied 750,000 men and women over a 20-year period and found that the people who were least aerobically fit were 4 times more likely to die from any cause compared to the fittest individuals. To put this in perspective, the negative impact of poor cardiorespiratory fitness on lifespan shown in this study was 6 times worse than the impact of smoking. Let that sink in for a minute! The results remained constant even when adjusted for other unrelated health problems in each of the fitness groups. This means that the study was able to look only at the impact of fitness itself and the results were not skewed by chronic health conditions often correlated with low cardiorespiratory fitness. Additionally, the protective benefit of high fitness levels held true when the study population was sliced and diced to look at different age ranges, different genders or different races.

In some ways however, these findings should not be surprising. The results are similar to those of a study published in the Journal of the American Medical Association (JAMA) back in 2018. Their results found a very similar dramatic drop in the risk of dying as patients improve their aerobic fitness. One thing that makes the newer study even more compelling however is that it included about 6 times as many patients. The study population was also much more well-rounded, including more than 127,000 patients aged 70-95, and also included nearly 200,000 non-white patients (groups that have been under-represented in previous similar studies). 

Based on the results of these and other studies, I have the following 3 takeaways:

1. Start somewhere and do something! You don’t have to achieve elite levels of fitness to see a benefit. In fact, the largest reductions in mortality are achieved simply by moving out of the lowest tier of fitness. If you can achieve even moderate amounts of fitness you can cut your risk of dying from any cause by more than 50%! In patients older than 70, having above average levels of fitness was associated with almost 3 extra years of life compared to those with the lowest levels of fitness.
2. Fitness can promote lifespan and health span! The positive benefits of fitness were observed at similar rates across each decade of life, even in patients >80 years old. So maintaining fitness levels as we age is key. It’s not just about longevity though. Those with higher levels of fitness had significantly less rates of chronic diseases like diabetes, high blood pressure, kidney problems and even cancer. Furthermore, those with higher fitness levels needed significantly fewer medications as well. So increasing your aerobic fitness is one way to live healthier, longer.
3. There is no upper limit of benefit! Although a lot of gains are achieved at the lower tiers of fitness, the results of this study can be motivating and reassuring for those that are already maintain a high level of physical activity. The reduction in mortality and the rates of chronic disease continued to improve at each tier of fitness. Additionally, contrary to previous studies, neither the JAMA nor the JACC studies found any negative impacts of training for, and achieving elite levels of cardiorespiratory fitness. Simply put, there is no medication that can have an impact as huge as aerobic fitness. Countless supplements come and go and do not show results anywhere close to this. There are most definitely no silver bullets in medicine, and nothing can guarantee increases in health span or lifespan. However, for those of us who are fortunate enough to experience aging, high levels of aerobic fitness appear to be as close as we can get!