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).[1]
Understanding the relationship between cardiorespiratory fitness and other categories of conditioning requires a review of changes that occur with increased aerobic or anaerobic capacity. As aerobic/anaerobic capacity increases, general metabolism rises, muscle metabolism is enhanced, hemoglobin rises, buffers in the bloodstream increase, venous return is improved, stroke volume is improved, and the blood bed becomes more able to adapt readily to varying demands. Each of these results of cardiovascular fitness/cardiorespiratory conditioning will have a direct positive effect on muscular endurance, and an indirect impact on strength and flexibility.[2]
To facilitate optimal oxygen delivery to the working muscles, an individual must train or participate in activities that build up the energy stores needed for sport. This is referred to as metabolic training. Metabolic training is generally divided into two types: aerobic and anaerobic. A 2005 Cochrane review demonstrated that physical activity interventions are effective for increasing cardiovascular fitness.[3]
Cardiovascular fitness measures how well the heart, lungs, 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.[4]
Physiology of the Circulatory System
[edit]The cardiovascular system collectively refers to the heart and the blood vessels (i.e. "vasculature") 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 right 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 left heart, where it is pumped to the rest of the body.
Cardiovascular "fitness" is defined as the ability of the heart and blood vessels to deliver deoxygenated blood to the lungs and deliver oxygenated blood to the whole organism. Many diseases and conditions can reduce cardiovascular fitness by three main mechanisms:
- Obstructing the flow of blood from the heart through the vessels (e.g. coronary artery disease, peripheral artery disease, atherosclerotic disease, stenosis, aneurysms, etc.)
- Inhibiting the flow of blood through the heart (e.g. valvular diseases (stenosis, sclerosis, ischemia to the papillae muscles), myocardial ischemia, constrictive pericarditis, etc.)
- Reducing the return of blood to the heart, referred to as "preload" (e.g. veinous insufficiency, orthostatic hypotension, deep vein thrombosis, pericardial effusion, etc.)
These diseases are collectively referred to as "cardiovascular disease." 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.
Assessing Cardiovascular Fitness
[edit]Cardiovascular fitness can be assessed through various methods, including maximal oxygen uptake (V̇O2max), 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.[1]
The Role of Exercise in Cardiovascular Fitness
[edit]Regular physical activity is essential for improving cardiovascular fitness.[1] 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. A 2020 review found that both moderate and high-intensity exercise improved cardiovascular fitness, but high-intensity exercise produced greater improvements.[5]
Types of exercise
[edit]Exercises that improve cardiovascular fitness are often referred to as "cardio exercises" or "aerobic exercise." These exercises include: walking, jogging, running, swimming, biking, jumping rope, etc.
Benefits of Aerobic Exercises on Cardiovascular Fitness
[edit]Aerobic exercise is the single most important factor in improving cardiovascular fitness in people who do not already have cardiovascular disease.
References
[edit]- ^ a b c Lin X, Zhang X, Guo J, Roberts CK, McKenzie S, Wu WC, Liu S, Song Y (June 2015). "Effects of Exercise Training on Cardiorespiratory Fitness and Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials". Journal of the American Heart Association. 4 (7). doi:10.1161/JAHA.115.002014. PMC 4608087. PMID 26116691.
- ^ Pate, Russell; Oria, Maria; Pillsbury, Laura; Youth, Committee on Fitness Measures and Health Outcomes in; Board, Food and Nutrition; Medicine, Institute of (2012-12-10), "Health-Related Fitness Measures for Youth: Cardiorespiratory Endurance", Fitness Measures and Health Outcomes in Youth, National Academies Press (US), retrieved 2023-07-28
- ^ Hillsdon, M.; Foster, C.; Thorogood, M. (2005-01-25). "Interventions for promoting physical activity". The Cochrane Database of Systematic Reviews (1): CD003180. doi:10.1002/14651858.CD003180.pub2. ISSN 1469-493X. PMC 4164373. PMID 15674903.
- ^ Kodama, Satoru (2009-05-20). "Cardiorespiratory Fitness as a Quantitative Predictor of All-Cause Mortality and Cardiovascular Events in Healthy Men and Women". JAMA. 301 (19): 2024–2035. doi:10.1001/jama.2009.681. ISSN 0098-7484. PMID 19454641.
- ^ Wang, Cuihua; Liu, Gang; Xing, Jun; Wang, Yahui; Zhao, Baoli; Zheng, Mingqi (2022). "The effects of high-intensity interval training vs. moderate-intensity continuous training on exercise tolerance and prognosis in heart failure and coronary artery disease: a systematic review and meta-analysis". Cardiovascular Therapeutics. doi:10.37766/inplasy2020.8.0112. PMC 9203221. PMID 35801132. S2CID 225297610.