Longevity Briefs: Exercise Intensity vs Volume – Which Is More Important For Longevity?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

We all know that exercise improves health and extends lifespan, but this relationship is hard to study and the specifics remain unclear. For example, while exercising for longer seems to correlate with reduced mortality (though with diminishing returns for higher levels of exercise), the importance of the intensity of that exercise is less clear, making it hard to give precise recommendations. The Word Health Organization recommends 75-150 minutes of vigorous activity or twice that amount of moderate activity per week. Is there an optimal combination of the two? Is it better to achieve a given workload through a shorter duration at higher intensity or a longer duration at lower intensity? Or is overall volume (that is to say the total work done, a product of both intensity and duration) the only thing that matters? These questions require further exploration. In this study, researchers investigate whether intensity or volume is more important when it comes to reducing mortality, particularly from cardiovascular disease.

The discovery:

Researchers looked data from the 2011–2014 National Health and Nutrition Examination Survey (NHANES), a large survey carried out in the USA. Specifically, they looked at data from 7518 participants (median age 49) who wore accelerometers, allowing researchers to estimate total time spent exercising (duration), time spent performing high intensity exercise (intensity gradient) and total work done (volume). They then tracked mortality over an 82 month period.

They found that higher intensity gradient was a stronger predictor of reduced all-cause and CVD mortality risk when compared to volume, though in both cases there were diminishing returns for the highest levels of activity. Being at the 50th percentile for volume (this means that 50% of people did less volume than this) was associated with a 14.4% reduction in all-cause mortality risk compared to the 25th percentile, while intensity was associated with a 37.1% reduction for the 50th percentile compared to the 25th percentile.

Interestingly, the benefits of volume were not statistically significant when cardiovascular deaths alone were considered, while intensity was associated with a 41% reduction in mortality going from the 25th to the 50th percentile. The researchers also found evidence that continuous bouts of high intensity activity, even as short as 5 minutes, were associated with greater mortality risk reduction than the same amount of intense physical activity spread sporadically throughout the day.

The implications:

This research suggests that while all exercise is beneficial, maximizing the time spent performing high intensity exercise might be particularly valuable, especially when it comes to preventing cardiovascular disease. Concentrating that high intensity activity into longer bouts may also be more valuable than spreading them throughout the day.

Since researchers also had access to other health information such as diet, they were able to control for confounding factors, but these controls are never perfect. People who exercise more are likely to be healthier in other ways, and this relationship might be stronger for high intensity exercise than it is for overall volume.