# Exercise as it relates to Disease/the role of resistance training in the management of coronary artery disease
### What is Coronary Artery Disease

Coronary artery disease (CAD) is the most common type of heart disease. affecting millions world wide, and without proper treatment or management will lead to a reduced quality of life and a drastically shortened lifespan.

### prevalence

Coronary heart disease or heart disease: currently affects around 1.4 million Australians, claimed the lives of over 20,000 Australians (almost 14% of all deaths) in 2012 and kills 55 Australians each day, or one Australian every 26 minutes. It is also the leading cause of death in the United States in both men and women.

### Causes

CAD happens when the arteries that supply blood to heart muscle become hardened and narrowed. This is due to the buildup of cholesterol and other material, called plaque, on their inner walls. This buildup is called atherosclerosis. As it grows, less blood can flow through the arteries. As a result, the heart muscle can't get the blood or oxygen it needs.

### effects

This can lead to chest pain (angina) or a heart attack. Most heart attacks happen when a blood clot suddenly cuts off the hearts' blood supply, causing permanent heart damage.
Over time, CAD can also weaken the heart muscle and contribute to heart failure and arrhythmias. Heart failure means the heart can't pump blood well to the rest of the body. Arrhythmias are changes in the normal beating rhythm of the heart.

## risk factors
### lifestyle related

* smoking
* obesity
* diet, particularly the fruit and vegetable intake
* levels of exercise

### clinical

* high blood pressure
* age, while CAD can affect people of any age the risk levels change through the lifespan
    risk factors for people aged 18-45
    risk factors for people aged 45 and over
* genetic pre-disposition

## resistance training
### what is resistance training

Resistance training works to increase muscle strength and endurance by doing repetitive exercises with weights, weight machines, or resistance bands.

#### benefits of resistance training

the primary benefit of resistance training is the increase of strength that will develop over the long term. other benefits include;
* increased bone density
* increased Lean Body Mass (LBM)
* increased Basal Metabolic Rate (BMR)
* decreased insulin reaction to glucose challenge
* increased insulin sensitivity

## treatment
### lifestyle changes

lifestyle changes are the primary defense against the onset of CAD and will often include not only exercise interventions but diet and weight management aspects as well. one such program that includes all of these aspects is the Therapeutic Lifestyle Changes (TLC). Your doctor may recommend TLC if you have high blood cholesterol.

#### diet

the primary aim of a diet that plans to aid in reducing the risk factors of CAD is to reduce the fat intake and over time reduce the amount of LDH or bad cholesterol while still allowing the consumption of HDH or good Cholesterol. for more information on a TLC diet plan click here

### exercise

while exercise is a major contributing factor in the management of CAD, before undertaking any exercise program regardless of the intensity level consult your doctor and complete a pre-screening tool to be certain that you are not within the group of people that due to pre-existing conditions or additional risk factors should not be completing physical activity of certain intensities
the basic principle of exercise programs utilized with CAD patients is as follows;
* duration of 20–30 minutes(preferably 45-60 min) of moderate intensity exercise, such as a vigorous walk or bike ride
* frequency of 2–3 days a week
* proportional to max heart rate (50-80%) or at 40-60% of heart rate reserve
* working at a rate of 10-14 on a 6-20 borg scale for rate of perceived exertion(RPE)

#### Resistance training as a treatment

resistance training for a long period of time was not deemed useful or safe in the treatment of CRD and other heart conditions however in the past 20 years research into this area has determined the positive outcomes of low to moderate intensity resistance exercise training far outweigh the potential risks, so long as the exercise is completed in a controlled environment and is supervised by experienced others.
a study published in the journal of the american heart association in the year 200 tested the effectiveness and prescription of resistance training in individuals with and without cardiovascular disease. this study determined that while resistance training could not replace an aerobic rehabilitation program its addition to a rehabilitation program could benefit patients significantly. the primary benefits were improvements in strength and lean body mass, but with the strength increases that were seen many patients who had lost confidence in their ability to perform day to day tasks regained a measure of confidence.
many national heart health organisations such as the heart foundation (Australia) and the american heart organisation now recommend that in addition to a cardiovascular training program patients be prescribed with a resistance training program.

### medicinal treatment/management

if lifestyle changes are unable to adequately reduce the risk factors and symptoms of CAD than a medical professionals only option would be to prescribe medication to reduce the risk factors or alleviate the symptoms. this is normally achieved through the use of medicines that;
* lower blood pressure
* reduce cholesterol levels
* reduce the likelihood of a blood clot forming
if the medicine is ineffective or administered to late in the process then there are surgical options for treating CAD these include:
* Percutaneous Coronary Intervention (PCI), commonly known as angioplasty, is a nonsurgical procedure that opens blocked or narrowed coronary arteries.
* Coronary Artery Bypass Grafting, (CABG) is a type of surgery. In CABG, arteries or veins from other areas in your body are used to bypass (that is, go around) your narrowed coronary arteries.

## Further reading

* American Heart Association Recommendations for Physical Activity in Adults
* national heart foundation physical activity recommendations for people with cardiovascular disease
* national heart foundation home page
* american heart association home page

## References

* Briffa T, Maiorana A, Allan R, et al. On behalf of the Executive Working Group and National Forum Participants. National Heart Foundation of Australia physical activity recommendations for people with cardiovascular disease. Sydney (Australia): National Heart Foundation of Australia; January 2006
* Essa.org.au, (2014). Adult Pre-exercise Screening System | ESSA. [online] Available at: https://www.essa.org.au/for-gps/adult-pre-exercise-screening-system/ [Accessed 30 Sep. 2014].
* Familydoctor.org, (2014). Arrhythmia | Overview—FamilyDoctor.org. [online] Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/arrhythmia.printerview.all.html [Accessed 30 Sep. 2014].
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