Cardiovascular fitness

Cardiovascular fitness is a component of physical fitness, which refers to a person's ability to deliver oxygen to the working muscles, including the heart. Cardiovascular fitness is improved by sustained physical activity (see also endurance training) and is affected by many physiological parameters, including cardiac output (determined by heart rate multiplied by stroke volume), vascular patency, and maximal oxygen consumption (i.e. VO₂ max).

Cardiovascular fitness measures how well the heart and blood vessels can transport oxygen to the muscles during exercise. It is an important component of overall fitness and has been linked to numerous health benefits, including a reduced risk of cardiovascular disease, improved cognitive function, and increased longevity. A study published in the American Journal of Epidemiology found that higher levels of cardiovascular fitness were associated with a lower risk of mortality from all causes, including cardiovascular disease and cancer.

This article addresses cardiovascular health as well as fitness, because the two are dependent on each other. However, "cardiovascular health" often refers to the normal, non-diseased function of the heart as defined by medical professionals. While the definition of health is still controversial and debated, it is frequently used in contrast to disease, whereas "cardiovascular fitness" further describes the performance of the heart and blood beyond normal functioning, or simply a non-diseased state. This article will focus on cardiovascular fitness, and reference health and disease to support this topic. For more information on cardiovascular health and disease, see cardiovascular disease.

The cardiovascular system collectively refers to the heart and the blood vessels, which include arteries, capillaries, and veins. The heart and vessels function to distribute oxygenated blood to the body's organ systems where oxygen diffuses into cells to aid in the generation of ATP (a molecule used throughout the body to as a form of energy). Once the oxygen diffuses into cells, the blood is then "deoxygenated" and returns to the heart, where it is pumped into the lungs to receive more oxygen. The blood is then considered "oxygenated" and delivered from the lungs to the heart again, where it is pumped to the rest of the body. For more information, see circulatory system.

Cardiovascular "fitness" is defined as the ability of the heart and blood vessels to deliver oxygenated blood to the whole organism. Many diseases and conditions can reduce cardiovascular fitness by three main mechanisms:

These diseases are collectively referred to as "cardiovascular disease" (CVD). Ultimately, reduced cardiovascular fitness can lead to heart failure and ischemia, reducing the body's aerobic metabolism of energy to the degree that cells die and the organ can no longer perform its function. Therefore, treatment and prevention of these disease is key to maintaining and improving cardiovascular fitness to optimize the function of the whole body.

Cardiovascular fitness can be assessed through various methods, including maximal oxygen uptake (V̇O_2max), which is the maximal amount of oxygen that can be used during exercise. Biomarkers, such as those used for assessing blood lipids, inflammation, glucose tolerance, and hemostasis, may be used to monitor progress during the development of cardiovascular fitness.

Regular physical activity is essential for improving cardiovascular fitness. The American Heart Association recommends at least 150 minutes of moderate-intensity aerobic exercise or 75 minutes of vigorous-intensity aerobic exercise per week to improve cardiovascular fitness and reduce the risk of cardiovascular disease.