Exercise as it relates to Disease/The effects of Physical Activity on Atherosclerosis

This is an analysis of the journal article "Relation of Carotid Artery Wall Thicknessto Diabetes Mellitus, Fasting Glucose and Insulin, Body Size and Physical Activity" by Folsom AR, Eckfedlt JH, Weitzman S, Ma J, Chambless LE, Barnes RW, Cram KB & Hutchinson RG (1994)

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Atherosclerosis. Author: National Heart Lung and Blood Institute (NIH)

What is the background to this research?

Atherosclerosis is the leading cause of mortality and morbidity in developed countries; such as United States of America and Australia. It is a coronary heart disease in which over a period of time fatty plaque is built up inside your arteries, causing a disrupted flow of blood to your heart and other parts of your body. This can cause serious implications to the body including; myocardial infarction (heart attack), stroke and even death.

The study looked at the relation of carotid artery wall thickness to diabetes mellitus, fasting glucose and insulin, body size and physical activity. The study population were individuals based in four US communities; Forsyth County, NC; Jackson, Miss; the northwest suburbs of Minneapolis, Minn; and Washington County, Md. This study population is also known as the Atherosclerosis Risk in Communities (ARIC). It was found that abdominal adiposity, physical inactivity and abnormal glucose metabolism were positively linked with carotid intimal medial wall thickness, suggesting these factors contributed to atherosclerosis.

To reduce the risk of atherosclerosis, it is important that you participate in regular physical activity, maintain a healthy weight, stop smoking immediately and enjoy a healthy, balance diet.

Where is the research from?

The study was carried out by researchers from the School of Public Health, University of Minnesota and North memorial medical Center, all in Minneapolis, Bengurion University in Israel, University of North Carolina in Chapel Hill and Ultrasound Reading Center, all in North Carolina, and University of Mississippi medical Center, in Mississippi.

The study acknowledges the support from various grant contracts from the National heart, Lung and Blood Institute and support from ARIC coinvestigators; special mentions were to Laura Kemmis, Larry Crum and Gretchen Marcucci for their contribution in helping prepare the manuscript.

What kind of research was this?

The research study noninvasively measured average intimal- medial carotid wall thickness by B-mode ultrasonography in cross sectional samples of 45 to 64 year old adults, both blacks and whites, free of symptomatic cardiovascular disease, in four US communities. It involved conducting a Case control study- comparing individuals with cardiovascular disease (CVD) and no CVD and individuals that were black or white, and a Cross sectional study- comparing mean wall thickness to various factors.

What did the research involve?

After informed consent, the 14430 participants conducted a home interview and clinic examination. During the home interviews, interviewers examined the participants’ assessment of socioeconomic factors, education level, smoking status, medication use, history of cardiovascular disease and diabetes mellitus. During clinic examinations, participants had their cardiovascular risk factors measured and a B-mode ultrasound examination of selected arterial sites.

Participants where asked to fast for 12 hours prior to the clinic examination. During process, a number of calculations and measurements where collected including.

• Blood specimens: this was collected to measure participants total cholesterol, triglycerides, low-density lipoproteins (LDL) and high-density lipoproteins (HDL).
• Body Mass Index (BMI)
• Waist to hip circumference: this was collected to assess fat distribution
• Physical Activity: This was assess by interview using a questionnaire developed by Baecke
• Blood Pressure: This was collected to measure participant’s prevalence to hypertension, diabetes mellitus and cardiovascular disease.

The main interest for researchers however was to calculate the average intimal-medial thickness of the far wall of the six carotid artery segments

What were the basic results?

The researchers resulted that abdominal adiposity, physical inactivity and abnormal glucose metabolism are associated positively with carotid intimal- medial all thickness, proposing these factors contributed to atherosclerosis.

What conclusions can we take from this research?

Physical inactivity is a major risk factor for any coronary heart disease and an exercise-training program must be implemented to in order to tackle this risk

It can be seen in a number of studies that individuals who participated in a physically active lifestyle where less likely to develop any coronary heart disease (atherosclerosis) when compared to individuals participating in a physically inactive lifestyle. Being physically active have shown to increase HDL concentrations, lower adiposity, triglyceride concentration and ratio of total cholesterol to HDL cholesterol. Regular physical exercise has also shown to increase coronary blood flow and improve endothelial function.

The Australian’s Physical Activity and sedentary behaviour guidelines for adults recommends accumulating 150–300 minutes of moderate intensity or 75– 150 minutes vigorous of physical activity or an equivalent combination of both moderate and vigorous each week. They suggest that doing any physical activity is better than doing none and being active on most, preferably all, days every week.

Changing dietary behaviour is just as important as changing physical activity behaviours. A change in dietary habits can decrease blood pressure and lower LDL. Health professionals may recommend the Dash (Dietary Approaches to Stop Hypertension) healthy diet plan. This diet is flexible and balanced with no special foods but instead provides daily and weekly dietary goals

Practical advice

Before starting any physical activity or dietary changes, it is critical that you consult your local health professional. An Adult pre exercise-screening (APSS) tool should be done with your health professional before commencing any physical activity. It is recommended that sedentary adults should avoid randomised bouts of vigorous activity and gradually increases physical activity overtime (5). The most common physical activity injury is musculoskeletal injury and participating in vigorous activity acutely increases the risk of sudden cardiac arrest, however this is very uncommon. It has been observed that exercise related cardiac event where greatest in the least active individuals.

The take home message for you is that, in order to reduce any risk of coronary heart diseases such as atherosclerosis; you must regularly participate in any sort of physical activity, Doing some is better than none.

Further information/resources

For further information on atherosclerosis and prevention follow the links below:

• Heart Foundation: http://heartfoundation.org.au/about-us/what-we-do/heart-disease-in-australia
• Nutrition Australia: Nutrition and Cardiovascular disease: http://www.nutritionaustralia.org/national/resource/cardiovascular-health
• Australian Institute of Health and Welfare: http://www.aihw.gov.au/cardiovascular-disease/what-is-cvd/