Coronary Artery Disease - The Benefits of ExercisePresentation Transcript
Coronary Artery Disease The Benefits of Exercise BY Michael Pratt Faculty of Health Sciences and Medicine
Importance & Significance of CAD INTRODUCTION
Coronary artery disease (CAD), which is the narrowing of the small blood vessels that supply blood and oxygen to the heart, is the most common form of heart disease in developed nations.
In Australia alone, CAD accounts for 17% of all deaths.1
According to the 2008 AIHW Report, the total expenditure on CVD in 2002/03 was $7.91 billion.
In 2032/33, as current trends follows this amount is expected to be $16.18 billion. This is a 105%change from 2002/03 to 2032/33.1
Atherosclerosis and hypertension are two conditions that can contribute largely to an increased risk of developing CAD.
Hypercholesterolaemia, referring to elevated serum cholesterol, increases the risk of developing both conditions.
Hypercholesterolaemia; characterised by increases in low-density lipoprotein cholesterol (LDL) and decreases in high-density lipoprotein cholesterol (HDL), increases plaque build up within the arterial walls causing atherosclerosis leading to elevated blood pressure, resulting in hypertension.
Link between exercise &CAD INTRODUCTION (Contin)
This plaque build up can eventually result in blockages leading to myocardial infarction, ischemia and stroke.
However, there is a clear link between CAD and physical inactivity. The World Health Report 2002 estimated that over 20% of CAD in developed countries is due to insufficient physical activity.2
In Australia, 54% of people aged 18–75 years do not undertake sufficient physical activity to obtain a health benefit, and nearly a third of these do no physical activity in their leisure time.3
Participating in regular exercise, however has been shown to provide significant benefits; such as increases in HDL and decreases in LDL.4
Through regular exercise it provides the best management and regression of CAD.
This presentation highlights the benefits of exercise for cardiac patients.
How exercise not only increases HDL cholesterol, but a wide range of other benefits.
Details how exercise is prescribed in this group; and
Considers safety and contraindications to exercise in this group.
Electronic computer searches (PubMed, Sport Discus, Cochrane Database of Systematic Reviews) were conducted to identify previously published meta-analyses that included primary outcome data on the effects of aerobic exercise on CAD risk factors.
The major keywords used in the searches included exercise, CAD, serum lipids and hypercholesterolemia.
All searches were limited to meta-analyses published and reviews.
Benefits of resistance training Table 1. Benefits of resistance or strength training5
Table 1 displays the benefits of both resistance and strength training.
Table 1 highlights the decrease in both LDL cholesterol and triglycerides due to resistance training.
This is also responded well by increases in HDL cholesterol.
Table 1 highlights that resistance (or strength) training is an important component of exercise for patients with CAD, despite previously held fears that it increased the risk of cardiovascular complications.5,6
Benefits of aerobic exercise Table 2. Benefits of aerobic exercise5
Table 2 displays the beneficial impact of exercise on pathophysiology, cardiac risk factors, physical function and psychological wellbeing.
Meta-analysis on 31 trials (n=1833)4 highlights that aerobic exercise increased HDL levels by 0.05mmol/L.
Aerobic exercise is shown by previous studies to be the most beneficial in improvements as a whole than resistance training.5
Effect of Exercise on Serum Lipids Figure 17
Figure 1 highlights that most studies demonstrate an increase in HDL with exercise training.
Meta-analysis in 25 trials (n= 1404)7
Average: 0.065mmmol/L increase in HDL
Those with lower BMI (<28kg/m2) and higher TC (5.7mmol/L) had the greatest response to exercise
This highlights the greatest potential for improvement.
Exercise guidelines Table 3. Guidelines for resistance training on cardiac patients5
Effect of exercise intensity and duration Figure 2.8 Figure 2 (contin)
Figure 2 highlights the effect of different exercise intensities and duration on HDL cholesterol.
This study done on 111 overweight men and women with moderate dyslipidaemia, displays that high-amount, high intensity is shown to best for all comparisons.
Low amount of exercise is shown to be always better than control.
Exercise training, both aerobic and resistance, is not only safe and beneficial in preventing CAD, due to improved lipid profile. But also improves in overall management once you have CAD.
As a result, most patients can expect to improve their exercise tolerance, functional ability and quality of life.
Additionally, risk of mortality and hospital readmission is also reduced as exercise training enhances cardiovascular function and helps to modify cardiac risk factors.5
Refrences: 1. Australian institute of health and Welfare (2008). Available at www.aihw.gov.au/cvd/index.cfm.2. World health organization. The World health Report 2002. Reducing risks, promoting healthy life. Geneva: Who, 2000. 3. Armstrong T et al.. Physical activity patterns of Australian adults. Results of the 1999 national Physical Activity survey. Canberra: Australian institute of health and Welfare, 2000.4. Halbert et al. (1999). Exercise training and blood lipids in hyperlipidemic and normolipidemic adults: a meta-analysis of randomized, controlled trials. Eur J ClinNutr. 1999;53:514-5225. Wise, F. (2010) Coronary heart disease; the benefits of exercise. Australian Family Physician Vol. 39, no. 3, March.6. Bjarnason-Wehrens B et al. Recommendations for resistance training in cardiac rehabilitation. Recommendations of the German Federation for cardiovascular Prevention and Rehabilitation. Eur J cardiovascPrev Rehabil;11:352–61 .7. Kodama et al. (2007). Effect of Aerobic Exercise Training on Serum Levels of High-Density Lipoprotein Cholesterol; A Meta-analysis. Arch Intern Med;167(10):999-1008.8. Kraus et al. (2007) Effects of the Amount and Intensity of Exercise on Plasma Lipoproteins. N Engl J Med 2002; 347:1483-1492