Why cardiorespiratory fitness is so important

High aerobic fitness is linked to an increased lifespan, reduced risk of disease, improved mental health and quality of life and lower levels of public healthcare expenditure

Cardiorespiratory fitness

Cardiorespiratory fitness is a measurement of a person’s ability to work with large muscle groups for sustained periods. This is also commonly referred to as aerobic fitness. Research has shown that aerobic fitness is extremely important for overall health and wellbeing. It is one of the strongest predictors for mortality and is a key risk factor for several lifestyle diseases such as cardiovascular disease and type 2 diabetes. At the same time, cardiorespiratory fitness is directly related to physical performance – both in terms of one's capacity to handle basic daily tasks, jobs and errands that are physically taxing, right through to athletic performance.

Association between cardiorespiratory fitness and life expectancy

Several large studies have shown that there is an inverse association between aerobic fitness capacity and mortality. In fact, a recent study showed that there is no upper limit to this. The more fit you are, the longer your expected lifetime (1). The mechanism behind this is two-fold. Aerobic exercise reduces the risk of most of the major lifestyle diseases like cardiovascular disease, diabetes and certain forms of cancer. This, of course, directly affects total expected lifespan. 

Additionally, aerobic exercise also increases functional capacity, prevents cognitive decline and improves self-perceived quality of life (2, 3, 8). These factors are all fundamental in maintaining a sense of purpose in life and a self-sustainable lifestyle well into old age..

Aerobic exercise as medicine

Aside from the fact that cardiorespiratory exercise has been proven to reduce the risk of disease and medical conditions, it is increasingly seen as a way of treating medical issues.
Aerobic exercise has been systematically used as prevention and rehabilitation after cardiovascular disease (3). In more recent times new research has shown that the same treatment effect is relevant for many other diseases (4).

A study published in JAMA in 2017 showed that among newly diagnosed type 2 diabetics, more than half of the test group were free of medication after one year. In this study, cardio was not the only part of the intervention, but it was the central part of the physical activity (5).

Also, when it comes to conditions relating to mental health and wellbeing, aerobic exercise is increasingly being recognised as a key factor, as is time spent in the outdoors.
In people of all ages, aerobic exercise improves cognitive function, and can be instrumental in preventing and / or reducing the effects of depression, anxiety and stress.
For the elderly aerobic exercise reduces cognitive decline and decreases the risks of Alzheimer’s disease and dementia (8).

Increasing the fitness levels of the public and decreasing the burden on the public healthcare system

As low aerobic fitness is related to increased risk of a range of chronic diseases which lead to early death, initiatives, campaigns or inventions that succeed in increasing aerobic fitness on a wider scale could have a virtually limitless impact on public healthcare costs. The potential economic benefits to the public sector of improved fitness levels in local populations are difficult to estimate, but several research studies have analysed healthcare costs relating to physical inactivity, and since poor fitness is a direct consequence of physical inactivity, this can be realistically applied as a relevant approach. 

A study published in Lancet in 2016 estimated that the worldwide cost of physical inactivity to be around $68 billion including productivity losses due to physical inactivity related deaths (9). By increasing fitness by only a few percent in the most inactive part of a given population, significant economic effects will be seen from reduced expenses for medication, healthcare, work absence due to illness, and early retirement. The question is not whether or not initiatives that improve population fitness are worth investing in; the question is just how extensive the level of investment should be, and how to identify initiatives, programs and campaigns that work.

What does it take to do efficient aerobic exercise?

It is known that physical activity with both low and high intensity can lead to major health benefits. However, exercise performed with low intensity requires longer sessions compared to high-intensity exercise, which can induce considerable improvements, even in short sessions. Interestingly, high-intensity interval training (HIIT), has been shown to be a feasible exercise form for most groups, including people with lifestyle diseases (6, 7). As time constraints are commonly cited by people as the main reason for physical inactivity, it makes sense to offer ways to exercise that are short, easy and time efficient.

The optimal strategy for physical activity for most people would be to satisfy current recommendations for daily physical activity and combine this with weekly sessions of targeted exercise. Preferably these would be in the form of interval training where high peaks of effort can be repeated several times. For most people, the easiest way to do this is by running or using low impact equipment like stationary bikes and cross trainers. This is only effective if the equipment offers sufficient workloads for the required intensities to be met.


A higher level of fitness is associated with a better chance for a long healthy life with a high functional capacity – not just physically, but also mentally. In the case of diseases, aerobic exercise is one of the most effective things that can be done to reduce symptoms or reverse pathology. Aerobic exercise can be done in a time-efficient and motivating fashion, when performed on exercise equipment that supports adequate intensity options. On society level, investments that improve population fitness are highly cost-effective.


1. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. Mandsager et al. JAMA Network Open. 2018;1(6)

2. The health benefits of physical activity and cardiorespiratory fitness. BCMJ, vol. 58 , No. 3 , April 2016 , 131-137.  McKinney J, Lithwick DJ, Morrison BN, Nazzari H, Isserow S, Heilbron B, Krahn AD, 

3. An Update on the Role of Cardiorespiratory Fitness, Structured Exercise and Lifestyle Physical Activity in Preventing Cardiovascular Disease and Health Risk. Ozemek C, Laddu DR, Lavie CJ, Claeys H, Kaminsky LA, Ross R, Wisloff U, Arena R, Blair SN. Prog Cardiovasc Dis. 2018 Nov 13.

4. Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases. Pedersen BK, Saltin B. Scand J Med Sci Sports. 2015 Dec;25 Suppl 3:1-72. 

5. Effect of an Intensive Lifestyle Intervention on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Clinical Trial. Johansen MY, MacDonald CS, Hansen KB, Karstoft K, Christensen R, Pedersen M, Hansen LS, Zacho M, Wedell-Neergaard AS, Nielsen ST, Iepsen UW, Langberg H, Vaag AA, Pedersen BK, Ried-Larsen M. JAMA. 2017 Aug 15;318(7):637-646. 

6. High-intensity interval training (HIIT) for patients with chronic diseases. Ross LM, Porter RR, Durstine JL. J Sport Health Sci. 2016 Jun;5(2):139-144. 2016 Apr 12.

7. High Intensity Interval Training for Maximizing Health Outcomes. Karlsen T, Aamot IL, Haykowsky M, Rognmo Ø. Prog Cardiovasc Dis. 2017 Jun - Jul;60(1):67-77. 2017 Apr 3.

8. Physical activity, diet, and risk of Alzheimer disease. Scarmeas N, Luchsinger JA, Schupf N, Brickman AM, Cosentino S, Tang MX, Stern Y. JAMA. 2009 Aug 12;302(6):627-37. 

9. Lancet. 2016 Sep 24;388(10051):1311-24. The economic burden of physical inactivity: a global analysis of major non-communicable diseases. Ding D, Lawson KD, Kolbe-Alexander TL, Finkelstein EA, Katzmarzyk PT, van Mechelen W, Pratt M. Lancet. 2016 Sep 24;388(10051):1311-24.