What does it mean to be fit? Which aspects of fitness matter the most? What is a “good” or an “excellent” standard of fitness to aim for, and why?

All of us will have a different answer to these questions based on our life experiences and interests, both athletic and otherwise. We all value fitness to differing degrees but it is very clear that being fit is not just about being stronger or faster than the next person. Rather, in achieving physical fitness we tap into our body’s natural longevity mechanisms to achieve optimal health and wellbeing and ward off chronic disease.

There are four aspects of fitness we focus on with our patients – all of which have strong evidence to support their correlation in achieving healthy longevity. These are:

1. Peak aerobic power
2. Aerobic efficiency
3. Muscle strength
4. Stability and Mobility

This article is the first of a four-part series focussing on each of the above measures of fitness and how to exercise for longevity and health.

First we will discuss what the science suggests is the measure of fitness most strongly corelated with longevity, your VO2 max, or your peak aerobic power.

The requirement of stress – hormesis

When the body is pushed out of balance temporarily by some potentially harmful external stress, the body adapts to restore balance. With adaptation comes improvement. The body becomes better prepared to deal with that same stressor again. This process is called hormesis.

Exercise is a form of hormesis. There are many other forms of hormesis – cold exposure, heat exposure and fasting are a few others worthwhile mentioning (look out for future posts on these!). As the above diagram shows, the dose makes the poison – too much of either of these stresses can be harmful rather than beneficial.

At the right dose and done regularly with slow progression, these powerful mechanisms of hormesis within the body can unlock natural health and longevity processes within the body, which build resilience against disease, illness and aging itself.

It therefore comes as no surprise that the fittest of humans, those who have given their bodies the most hormetic stress tend to be the ones who enjoy a longer health span.

Mitochondrial health – the greatest marker of health?

Our mitochondria are the energy factories within every cell in our body. They use oxygen to convert the food we eat into energy used for almost every process within our body. As we age, these mitochondria can become dysfunctional and less efficient – this can leave you feeling fatigued as well as contribute to a huge number of diseases including diabetes, Alzheimer’s disease and cardiovascular disease.

Indeed the maximum rate at which our body is able to consume oxygen to produce energy has been shown to be the fitness metric most strongly correlated with health and longevity. This maximum rate, your peak aerobic power, is what is defined as your VO2 max.

How to improve your VO2 max, and longevity

High intensity interval training (HIIT) is perhaps the most time efficient way to improve your VO2 max. As a rough guide, this might involve intervals as short as 20-30 seconds of all out effort, or the maximum effort you can output for between 1-4 minutes.

Again, hormesis is the key here in forcing the body to adapt to the transient stress. When your mitochondria are firing on all cylinders trying to meet the energy demands of your muscles, they will signal your cells to build more mitochondria for the next time!

More Mitochondria = More Energy = Better health and longevity!

HIIT needs to be done with a little caution, particularly for beginners as it can also be very taxing both on the joints and neurological system, potentially increasing risk of injury or overtraining. For this reason, we suggest that this type of training should ideally not form more than 20% of your aerobic training. Doing just 10-15 minutes of HIIT a few times a week is a great place to start.

Small steps, big gains

A study looking at how the VO2 max of people in their 50s impacted their risk of dying showed some dramatic results. It would come as no surprise if I told you that the higher your VO2 max, the less likely you were to die in the following 10 years. However things get very interesting looking at the details of the results, as shown below in this chart adapted from the data.

The people in the bottom 25% on the VO2 max leader board (low VO2 max) were 5 times more likely to die in the next 8 years than those in those in the top 5% (Elite level VO2 max). To put this into perspective, the chart also shows that someone who smokes is only 40% more likely to die in the next 8 years than someone who doesn’t smoke. A similar analysis in this study of risk of death for coronary heart disease is a 29% increase.

This may sound surprising to some people that being unfit increases your risk of dying several times more than some of these diseases that people worry much more about having. It really speaks again to what this aspect of fitness is a sign of, mitochondrial health, which is so fundamental to health and longevity.

Another important point to note from this study is that just going from low (lowest quartile) to below average (in the second lowest quartile) of VO2 max cuts your risk of dying in the next 8 years almost in half! This means you don’t need to be aim for an elite level of fitness to gain big benefits. You can still get some big value out of just pushing your aerobic fitness in the right direction even a little.

Know your goal

Below is a fantastic graph from the book Outlive, by the great Peter Attia, which shows 2 things:

1. The rate of oxygen consumption required for various activities.

2. How much on average VO2 max declines with age and by fitness level.

Using this graph, it is easy to perform a mental exercise where you think about what you want to be able to do at say age 80, and working backwards to decide what VO2 max you should be at right now. For some of us our goal at 80 may may be walking up a slight incline to the shops and carrying our bags back, for others it may be hiking up our favourite hill or a mountain.

At Agami Health, this is something we discuss with all our patients to help create clear goals when we are tailoring their exercise plans. We offer a VO2 max test for all our patients not only to assess where they are right now, but using this test we are also able to tell you exactly what intensity of exercise you need to be doing to reap the most benefits.

Contact us at Agami Health to arrange a free initial consultation to discuss how we can help you in your journey towards health, wellbeing and longevity.