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ADDING LIFE TO YOUR YEARS: THE HEALTHSPAN

Lifespan is the number of years you live. Healthspan is the quality of those years.

While average life expectancy has increased, it does not necessarily mean we’re living longer in better health. Current data (2026) published by the Office for National Statistics shows the average years lived vs total years lived in good health.

Life Expectancy

Healthy Years Lived

Healthy Years Lived With Poor Health

79 years

61 years

18 years

Men

83 years

61 years

22 years

Women

This means, on average, UK men live 23% and women 27% of their lives in poor health. This is the lowest UK healthy life expectancy (healthspan) since 2013.

Physical activity consistently emerges as the most important factor influencing both absolute physical capacity and the rate of age-related decline

Individuals who maintain higher levels of muscle strength and cardiorespiratory fitness generally retain greater physical reserve, allowing them to maintain function, independence and health for longer as they age.

High functional physical capacity compresses the period of sickness, disability, and frailty toward the very end of life. Termed compression of morbidity, this strategy enables individuals to live vibrant, self-sufficient lives for longer, limiting severe ill-health to a brief period at the end of the lifespan

Physical capacity generally peaks in our mid-30s and without intervention, cardiorespiratory fitness declines by approximately 10–15% per decade. Individuals may lose 3% to 8% of their muscle mass per decade and around 30–50% by the age of 80.

The physiological changes contributing to decreased health, reduced independence, and frailty can begin well before we experience signs and symptoms.

Health, function and independence

High cardio respiratory fitness and high strength

Low cardio respiratory fitness and low strength

Frailty and independence loss threshold

20 30 40 50 60 70 80 90 100

Age (years)

The Two Pillars: Cardiorespiratory Fitness & Skeletal Muscle Strength

Pillar 1: Cardiorespiratory fitness (CRF)

Definition

The capacity of the circulatory and respiratory systems to supply oxygen to skeletal muscle for energy production during sustained physical activity.

How do we measure it?

It is measured through oxygen uptake (VO₂). VO₂ is the volume of oxygen your body consumes at any given moment during exercise or at rest, reflecting your current energy demand and effort level.

It is expressed as milliliters of oxygen per kilogram of body mass per minute (ml / kg / min).

VO₂ max (maximal oxygen uptake) is the size of your engine. It measures the maximum volume of oxygen that your body can take in and transport to your cells to generate energy during maximal exercise.

VO₂ max testing is unrealistic and unnecessary for most individuals. Therefore, sub-maximal tests (performed at a reduced intensity and/or for a shorter duration) can be used to gather data which can be extrapolated to a predicted VO₂ max.

Additionally, METs can be used to describe exercise intensity.

A MET is a ‘metabolic equivalent’
- 1 MET represents our resting oxygen consumption. In volume of oxygen terms, this equates to 3.5 ml / kg / min

Activity Level

METs

Activity Example

Light

1 MET (3.5 ml / kg / min)

Sitting quietly

3 - 3.5 METs (10.5 - 12 ml / kg / min)

Walking at 2-3 mph

5 - 7 METs (17.5 - 24.5 ml / kg / min)

Playing recreational tennis

Moderate

10 METs (35 ml / kg / min)

Vigorous

Jogging at 6 mph

or vigorous swimming

15 METs (52.5 ml / kg / min)

Running at 8mph or vigorous skipping rope

20 METs (70 ml / kg / min)

Competitive cross

country skiiing

Why is CRF important?

Higher cardiorespiratory fitness is consistently associated with lower all-cause mortality. CRF is a reflection of the combined function of the heart, lungs, circulation and blood vessels, skeletal muscle cells and the nervous system. It reflects the performance of several interconnected physiological systems. This makes CRF a valuable indicator of physiological health and reserve.

CRF is considered one of the strongest indicators of overall health and longevity. Low CRF is strongly associated with an increased risk of cardiovascular disease, metabolic disease and all cause mortality.

Due to its strong predictive value for health outcomes, the American Heart Association has called for cardiorespiratory fitness to be considered a vital sign.

Each 1 MET increase in fitness is associated with an 11-17% lower relative risk of all-cause mortality.

Moving from low to moderate levels of cardiorespiratory fitness is associated with a lower risk of developing:

Cardiovascular disease

Type 2 diabetes

Hypertension

Certain cancers including colon and breast cancer

Chronic respiratory conditions

Metabolic syndrome

Cognitive decline

Depression/anxiety symptoms

Moving from low to above-average fitness has been shown to deliver health benefits equivalent to or greater than quitting smoking and managing high blood pressure.

Pillar 2: Muscle Strength

Definition

Muscle mass: the total amount of skeletal muscle tissue in the body
Muscle strength: the ability of muscles to produce force against resistance

How do we measure it?

Muscle mass can be measured with a DEXA scan or bioelectrical impedance analysis. To test muscle strength we can perform clinical tests such as a hand grip test using a dynamometer, repetition maximum tests (how much you can maximally lift for a predetermined number of repetitions e.g., 1, 5, 10), and manual muscle testing.

Why is muscle mass and strength important?

Skeletal muscle mass and muscular strength are inversely associated with all-cause mortality. Each 5kg decline in grip strength (grip strength acts as a proxy for overall muscle strength) is associated with a 16% increased risk of all-cause mortality.

Skeletal muscle muscle acts like a big metabolic sponge. It disposes of approximately 80% of circulating blood glucose, making it a key defence against type 2 diabetes, insulin resistance, and metabolic syndrome.

It also takes the form of physical "armour", with higher levels of strength being associated with reduced risk of:

Frailty and falls

Poor bone health, including osteoporosis

Sarcopenia, characterised by low muscle strength and confirmed by low muscle mass

Muscle is an active endocrine organ that regulates physiological processes and maintains health.

When your muscles contract during exercise, they release substances called myokines into circulation. These are proteins that communicate with other tissues and organs, including the brain, the vascular system, the liver and pancreas, body fat and the immune system. Think of it as your own internal pharmacy delivered by your own internal postal service. Muscle tissue and myokines help to:

Reduce systemic inflammation

Increase fat oxidation

Support tissue repair and remodelling

Improve cognitive function and neuroplasticity (the brain’s ability to adapt and change)

Increasingly, evidence points towards the importance of maintaining muscular power. As we age, muscle power declines at a faster rate than muscle strength due to the loss of type 2 (fast twitch) muscle fibres and a reduction in nerve supply to muscles. Because Type 2 muscle fibers generate explosive force, a loss of this impairs the rapid force generation necessary to regain balance after tripping, directly heightening fall risk and physical dependency.

Can we do anything about this?

YES! :D

Cardiorespiratory fitness and muscle strength are key modifiable factors influencing our current health and the number of healthy years (the healthspan) that we will live.

Exercising across the lifespan has the potential to offer us our greatest physical reserve as we age, but the good news is we can benefit regardless of the age we begin. A recent review showed that resistance training improved muscle strength in individuals aged 80 and above. Adaptations may be slower and smaller when we’re 80 compared to when we’re 30 but they are real and they are important.

Conclusion

What To Do?

To optimize your healthspan and preserve functional capacity, aim to incorporate both aerobic exercise and progressive resistance training into your routine. Following global guidelines, target at least 150 to 300 minutes of moderate-intensity aerobic activity (or 75 to 150 minutes of vigorous activity) per week, paired with targeted muscle-strengthening exercises on two or more days. Prioritizing both cardiorespiratory fitness and muscular strength builds a robust physical reserve, helping to delay or compress age-related decline and lower the risk of chronic conditions.

For those with chronic conditions such as osteoarthritis, hypertension and type 2 diabetes, the evidence is clear that this is an indication for targeted exercise, not a reason to avoid it.

Clinical exercise physiologists specialise in the prescription of evidence-based, personalised exercise programs to elevate your cardiorespiratory fitness, improve strength and power, and protect your independence. The exercise prescribed will be targeted to address your individual needs, medical history, exercise history, preferences and goals.

The Vitruvian Team.

References