Exercise as it relates to Disease/Exercise Effects on Cardiovascular Ageing

Cardiovascular disease, also known as heart disease, plays a major role in the high morbidity of our increasing ageing population. Cardiovascular ageing is considered a perpetual and irreversible progression which appears to be a strong determining factor of an elderly person’s quality of life and independence[1][2]. Exercise training and physical activity are known to have beneficial health effects, and now recent studies have convincingly reinforced the theory that exercise can positively reduce various cardiovascular risks factors and disease[2].

Background
Cardiovascular disease includes all diseases of the heart and blood vessels and accounts for 50% of all deaths in developed nations. Incidences of cardiovascular diseases increase linearly with age[6]. Genetics may present individuals with a predisposition to certain risk factors such as hypertension and hypercholesterolaemia. Advances in genomic technologies have allowed researchers to investigate the link between genetics and cardiovascular disease. Understanding the genetics underlying cardiovascular disease mechanisms will help reduce risk factors.

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Cardiovascular Disease Risks =====

Despite the unmodifiable risk factors, cardiovascular disease risk can be reduce by following a healthy lifestyle[9].

Endothelial Ageing and Physical Activity
Endothelium is the layer of cells lining our blood vessels and plays an important role in managing cardiovascular health. Endothelial cells produce nitric oxide (NO) which plays an important role in vasodilation and inflammation. When NO is released, it decreases blood pressure by stimulating a relaxed response from the blood vessels[10]. Alterations to the endothelium result in endothelial dysfunction and a decreased capacity to produce NO. Ageing is considered an independent risk factor for cardiovascular diseases and therefore causes a gradual decline in endothelial function and production of NO[10].

Physical activity improves endothelial function by enhancing the production of NO. Exercise also enhances shear stress which further stimulates the production of NO. Shear stress is the force of blood flow exerted against the endothelial walls[3]. Greatest physical activity benefits are seen in individuals with impaired endothelial function[3]. Regular exercise enhances the body’s capacity to use insulin, increases levels of high-density lipoprotein (HDL) cholesterol, lowers blood pressure and has beneficial effects regarding adipose tissue management[3]. As a result, exercise can help prevent cardiovascular disease risks such as high blood pressure, high cholesterol, diabetes and obesity.

Recommendations
Habitual exercise and training has the potential to control endothelial dysfunction caused by cardiovascular ageing[4]. Both aerobic endurance and resistance training can help reduce cardiovascular disease risk and improve lipid profiles[4].

Aerobic Endurance Exercise
Aerobic endurance exercise promotes beneficial decreases in fat mass, resting heart rate and blood pressure[4]. This form of exercise helps to reduce the age-related losses in endothelial function by restoring NO accessibility[10].
 * Frequency: 3 days per week[2] * Duration: 45–60 minutes sessions[2]  * Intensity: 60-85% of maximum heart rate (HRmax)[2]

Resistance Exercise
Resistance training enhances bone mineral density and improves muscular strength[11]
 * Frequency: 2–3 days per week * Duration: Single set of 8-10 different exercises, with 8-12 repetitions for healthy participants aged 50–60 years, or 10-15 repetitions at a lower resistance for cardiac patients and healthy subjects older than 60 years.  [11]

High Intensity Exercise
New research suggests high intensity circuit training is more effective in improving blood lipid pofiles, compared to low-intensity circuit or endurance training[4]. Other research suggests high intensity, multipurpose exercise programs with considerable training volumes can positively reduce cardiovascular disease risks in post-menopausal years for women[2].

Supporting Studies


 * A 2013 peer reviewed study regarding Effects of High-intensity circuit training on blood pressure and lipoproteins in middle-aged overwight men collected data from 41 subjects over a 12 week training period. When compared to low-intensity or endurance training, high-intensity exercise was consistently associated with greater cardiovascular benefits including reduced diastolic blood pressure, decreases in low-density lipoprotein (LDL) cholesterol, increases in HDL cholesterol and an overall greater decrease of triglycerides[4].
 * A 2013 study from the University of Erlangen-Nuremberg Institute of Medical Physics investigated the Long Term Exercise and Risk of Metabolic and Cardiac Diseases. This investigation was a 12 year follow-up study using recorded data from 1998 and established that high-intensity, multipurpose exercise programs greatly reduced cardiovascular risk scores of the women assessed[2].