Introduction
There is a powerful treatment that effectively delays the onset of death and preserves healthspan. This treatment is called exercise, and no other treatment or drug rivals its ability to prevent chronic illness.
The problem: it requires consistent effort and commitment over time and the myriad benefits of exercise cannot be packaged and sold as a medication. However, the long-term benefits of regular exercise, such as improved cardiovascular health, lower blood pressure, stronger muscles and bones, and better mental health, far outweigh the effort required to maintain an active lifestyle. These benefits also reduce the reliance on medication to prevent chronic diseases from developing.
The emerging science of longevity and optimising healthspan has seen increasing interest in both scientific and public forums. Much of the hype around longevity has surrounded advances in biology, with suggestions that pharmacological agents could target cellular aging processes and slow aging. There is little evidence to suggest this. There is however, evidence that exercise impacts both lifespan and healthspan. This becomes increasingly evident when reviewing the scientific literature on the impact of exercise on health parameters associated with aging.
The beauty of exercise is that it targets the whole human synergistically: from cellular processes through to multiple body systems and organs. The outcome of the right exercise prescription is an upgrade toward superior physiological and anatomical health. This upgrade comes with countless benefits, including suppressing the pathogenesis of all the major leading causes of death e.g. cardiovascular disease and cancer.
In this extended article on endurance training for longevity, I'll be breaking down the profound effect of improving cardiorespiratory fitness on lifespan.
What is endurance training?
Endurance training improves the body's ability to sustain physical activity over time. The primary focus of endurance training is to improve the aerobic system, which is responsible for the body's ability to use oxygen to produce energy during prolonged exercise.
There are different types of endurance training:
- Medium intensity continuous training (MICT)
- High-intensity interval training (HIIT).
These types of training can be further broken down into zones that categorise the underlying physiology. For example:
- in Zone 2, the body is performing at a moderate intensity and primarily using fat as a fuel.
- In Zone 5 the body is performing at a high intensity and primarily using glucose as a fuel.
Each type of training utilises different muscles and biochemical pathways provoking specific adaptations in the body. We will be going on to look at these in detail.
Endurance can be measured using various markers such as heart rate, power output in cycling, pace in running and VO2 max (traditionally tested in a lab and explained in detail later)
Seeking to improve these parameters have traditionally been the focus of athletes or serious amateurs. However, these are of fundamental importance for anyone serious about prolonging their healthspan.
The link between VO2 max and longevity
Going from below average to above average fitness can lead to a 60% to 70% reduction in the relative risk of mortality.
A recent study in the Journal of the American Medical Association found a strong link between cardiorespiratory fitness, as measured by V̇O2 max, and all-cause mortality.
- The study measured 122,000 participants VO2 max and followed them for an average of 10 years.
- It found that those in the lowest fitness level had a 5-fold increased risk of death compared to those in the highest fitness level.
- The study also found that going from a low fitness level to any other group above average brought about greater reductions in the risk of mortality than any of the diseases measured in the paper.
Figure 1. Patient survival by performance group. (Mandsager et al., 2018)
The hazard ratio of a low fitness level compared to an elite fitness level is 5.
This means that study participants with a low fitness level died at a rate 5 times higher than their elite counterparts. Converting this to risk reduction of the hazard ratio, one would be looking at an 80% reduction in all cause mortality.
Going from being low fitness to being below average is a 50% reduction in mortality.
Higher fitness correlated with risk reduction in mortality throughout the whole study. To put this into context, the study uses smoking as a comparison, smoking carried a 1.41 increased risk of all cause mortality to those not smoking. This comparison cannot be emphasized enough: being at a low fitness level compared to elite carries a risk of death 5 times that of their elite counterparts. This can be seen in the figure below.
Figure 1.2: Adjusted hazard ratios for comorbidities and between performance groups. CAD indicates coronary artery disease; and ESRD, end-stage renal disease.Mandsager et al., 2018
Elite was not defined as describing an elite athlete but rather the highest performing group in the sample (top 5%) The rest were ranked into quartiles— low, below average, above average and high fitness levels (shown in the figure below)
Figure 1.3: Classification of Cardiorespiratory Fitness by Age and Sex* — reproduced from Mandsager et al., 2018
To summaries, this paper puts into context how much of an improvement we can make in our overall lifespan, by improving fitness. Going from a low fitness level to any other group above average brought about greater reductions in the risk of mortality than any of the diseases measured in the paper.
Next we will look at what V̇O2 max is (the primary measure of fitness in this study) and how to improve it and what adaptations this provokes in the body.
Nice article Nathan – this highlights the important role regular participation in aerobic activity has on our lifespan – this can often be overlooked in favour of quick fix health strategies!