Poor Cardiorespiratory Fitness

Cardiorespiratory fitness (CRF) represents an objective measurement of an individual’s ability to use oxygen to convert chemical energy (oxidation of food and stored energy – fat and glucose) into mechanical energy. It has been know since 1995 that poor CRF is an independent risk factor for the development of cardiovascular disease and all-cause mortality (1). A recent publication in JAMA Network Open, established that poor CRF increases a persons risk of all-cause mortality to the same level as having type II diabetes or smoking (2). Smokers and type II diabetics have a 40% greater odds of all-cause mortality than their non-smoking and non-diabetic counterparts. These are significant increases in hazard ratios that are easily avoided.

While the publication does advise health care professionals to encourage patients to achieve and maintain high levels of fitness it fails to point out that “10,000 steps” are usually not enough to help individuals achieve the level of fitness to significantly reduce this risk. The fact is, walking while better than being sedentary is not a “dose” of exercise that will increase fitness in anyone other than those with the lowest CRF, such as those that are bed ridden or highly deconditioned. While this is a GREAT goal just a little more of the right exercise could be the difference between a slight improvement in fitness and a small risk reduction and excellent fitness and a significant risk reduction.

Another glaring failure of this publication is not mentioning that it is easy to measure CRF and CRF can be done easily, <15 minutes, by exercise professionals. In our opinion, CRF should be considered a vital sign of health and should be evaluated in patients. Unfortunately, healthcare fails to evaluate or monitor this powerful indicator of health. Here at Restore Medical Fitness all patients’ CRF is measured monthly, for those beginning programs, or in the case of those that have achieved higher levels of CRF, quarterly.

CRF is a major contributor to an individuals ability to perform work, perform physical tasks and complete normal activities of daily living. When we say “work” you might think of loading trucks but you can also think of things like dancing, playing with children, raking leaves, grocery shopping, mowing the lawn, gardening and walking. Individuals with good CRF can do all those things easier than those with poor CRF. These abilities are, in part, activities that determine the quality of a persons life.

Just as important as comfortably living with the ability to do more activities, CRF is a modifiable indicator of long-term mortality. Engaging in appropriate physical activity and exercise will influence your level of CRF and having better CRF improves your odds of living a long and happy life.


1 – Blair, et. al., JAMA, April 1995, Vol 273. No 14 – Changes in Physical Fitness and All-Cause Mortality

Conclusions: Men who maintained or improved adequate physical fitness were less likely to die from all causes and from cardiovascular disease during follow-up than persistently unfit men. Physicians should encourage unfit men to improve their fitness by starting a physical activity program.

 2 – Mandsager, et. al., JAMA Network Open, 2018;1(6):e183605 – Association of Cardiorespiratory Fitness with Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing

Conclusions and Relevance: Cardiorespiratory fitness is inversely associated with long-term mortality with no observed upper limit to the benefit. Extremely high aerobic fitness was associated with the greatest survival and was associated with benefit in older patients and those with hypertension. Cardiorespiratory fitness is a modifiable indicator of long-term mortality, and health care professionals should encourage patients to achieve and maintain high levels of fitness.