Andy Galloway explores the risk of the silent killer, atherosclerosis!
By Andy Galloway
Surrey Sports Park attracts a wide variety of people, from members of the public wanting to lose weight to elite athletes attempting to qualify for the national team. Being a member of a fitness facility, you probably understand the health benefits of exercise, but have you ever considered that you may still be at risk of cardiovascular disease?
It is well known that obesity is a major risk factor for cardiovascular disease – the world’s number 1 killer - however, this is also the easiest to spot. Less obvious risk factors include high blood pressure, insulin resistance and high cholesterol. You are far more likely to suffer from one of these conditions if you are older or don’t exercise, but it is important to understand that these conditions can affect adults of any age and activity level.
There are many different types of cardiovascular disease, but this post will focus on atherosclerosis which is an arterial disease characterised by fatty deposits building up inside the artery wall. These deposits form plaques which can break off and prevent blood flow causing a heart attack or stroke. The main factor required for atherosclerosis to develop is high cholesterol (2) which can be caused by smoking, inactivity and a poor diet. Cholesterol is needed by our bodies and produced in the liver, it is carried in the blood via lipoproteins. High density lipoprotein (HDL) is ‘good’ as it carries cholesterol from where there is too much back to the liver for disposal, whereas low density lipoprotein (LDL) is bad as it carries cholesterol from the liver around the body. Too much LDL is what can cause fatty deposits in arteries and restrict blood flow.
Cholesterol is regulated by the liver but we can also control production through our diet. HDL can be increased through consumption of foods high in omega-3 fatty acids such as nuts, seeds and oily fish whereas LDL can be increased through consumption of foods high in saturated fat and dietary cholesterol such as meat (1, 10), eggs (4, 11) and dairy (13).
It is easy to think that atherosclerosis would only affect older people but it actually begins in childhood, with most children showing fatty streaks in their arteries by the time they are 10 years old (15). A study of 300 autopsies on US military personnel recovered from the Korean War found that 77% showed clear and visible signs of atherosclerosis (5). These were fit, young men with an average age of 22 years old, showing that this is a disease which can affect people of any age. These results highlight the importance of considering our cholesterol levels at any stage in our lives.
In order to reduce the risk of developing any cardiovascular disease, it is recommended that people complete a minimum of 150 minutes of moderate intensity exercise per week. Resistance (weight) training is great for increasing strength and improving performance in your chosen sport, but it also has health benefits such as increasing insulin sensitivity in individuals with type-2 diabetes (9) and reducing blood pressure (3). Wooten found that resistance training was even successful in reducing cholesterol in post-menopausal women, however, results in other studies have been mixed. For example, one study (6) found that aerobic exercise (such as running or cycling) reduced LDL in obese people but resistance exercise did not. Therefore, both aerobic and resistance training methods should be combined in order to maximally reduce an individual’s risk of cardiovascular disease.
Dietary guidelines are shown on food packages and promoted in government initiatives, but many of us don’t understand what they mean when it comes to actual food. The American Heart Association recommend that saturated fat makes up no more than 6% of total calories which is approximately 13 g/day for someone eating 2000 calories. This is equivalent to approximately 2.5 slices of mature cheddar cheese or 5 rashers of bacon. It is estimated that Americans currently get 11% of their calories from saturated fat (8), almost double the recommended amount. The USDA recommends a maximum cholesterol intake of 300 mg/day which is equivalent to 1.5 large eggs or 4 pieces of fried chicken. UK Dietary Guidelines do not give a restriction on cholesterol intake as saturated fat is considered to have a greater effect on blood cholesterol levels. That is unless you suffer from familial hypercholesterolaemia, where an individual (at least 1 in 500 people) may have up to quadruple the cholesterol levels of an average person. This condition can lead to early onset of cardiovascular disease unless detected (see final paragraph) and treated. In the UK If you suffer from familial hypercholesterolaemia, you are recommended to not exceed 300 mg/day.
Nutrition or Exercise – Which is more important?
Some people may argue that they do lots of exercise so don’t have to worry about saturated fat and cholesterol. A 2007 study (7) compared age and BMI matched sedentary vegans with runners (averaging 48 miles per week for 21 years) eating a Western diet (high saturated/trans-fat, low fibre). They measured the thickness of the middle layer of the main artery (measure of atherosclerosis) in the neck in each group and found that the vegans who did less than 1 hour of exercise per week had the same artery thickness as the group of runners. This suggests that it is possible to have healthy arteries by either exercising a lot OR eating a very healthy diet, however, it is unlikely that many people will suddenly want to turn vegan or start running almost two marathons a week. A more reasonable aim would be to limit intake of saturated fat and cholesterol, increase fruit and vegetable consumption and incorporate both aerobic and resistance training into your workouts.
How we can help?
At Surrey Human Performance Institute we offer the NHS Health Check (free for those eligible) and a basic health check (£40) which measure many of the risk factors for cardiovascular disease. For more information or to book in your free check get in contact.
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