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Hot topic - Being unfit is more risky than being fat13 September 2004 - written by BUPA's Health Information Team Being inactive is a bigger risk factor for heart disease than obesity, a study in the 8 September edition of The Journal of the American Medical Association (JAMA) has shown.1 What do we know already?We know that being inactive and overweight are risk factors for heart disease. What we don't know is the individual contribution of each of these risk factors in people who already have symptoms of heart disease. What did the study show?Fitness may be more important than overweight or obesity for heart disease risk in women.1 The study concluded that being unfit and inactive is associated with risk of going on to suffer a heart attack or other serious problem, in women who are normal weight, overweight or obese. How was the study carried out?Researchers looked at the occurrence of the following conditions in almost 1,000 women with suspected heart disease:
The researchers then looked at the obesity and fitness levels of the women who had these conditions.1 How does physical activity affect heart disease risk?Physical activity halves the risk of developing heart disease.2 It helps your heart become stronger so that it can pump more blood around your body with less effort. High blood pressure (hypertension) is one of the major risk factors for heart disease. Physical activity helps to lower high blood pressure and prevent high blood pressure from developing.2 It may also help in improving blood circulation. For more information, please see the BUPA factsheet on high blood pressure at: http://hcd2.bupa.co.uk/fact_sheets/html/Hypertension.html Regular exercise seems to raise HDL cholesterol levels. Cholesterol comes in two forms - high levels of LDL ("bad") cholesterol promote the risk of heart problems, whilst high levels of HDL ("good") cholesterol are good for you.2 A heart attack usually occurs when blood clots form over a fatty substance (atheroma) in the coronary arteries (arteries feeding the heart). Regular physical activity helps to prevent blood from clotting.2 For more information, please see the BUPA factsheet on heart attack at: http://hcd2.bupa.co.uk/fact_sheets/html/heart_attack.html Physical activity also reduces the risk of having a stroke.2 For more information, please see the BUPA factsheet on stroke at: http://hcd2.bupa.co.uk/fact_sheets/html/Stroke.html How does obesity affect heart disease risk?Obesity increases the workload of your heart, making it harder for your heart to pump blood around your body efficiently. The more work the heart is doing the higher the pressure, so obese people are more likely to have high blood pressure. High blood pressure puts you at a greater risk of having a heart attack or a stroke. Being overweight may increase levels of LDL ("bad") cholesterol and reduce levels of HDL ("good") cholesterol. Heart disease is the main risk associated with high cholesterol. Although obesity does run in families, the most likely cause of being overweight is related to eating habits - a diet that is high in fats, sugar and alcohol. A high proportion of fats and "bad" cholesterol in the blood contribute to the build up of fatty material in the arteries which cause heart disease. A high salt intake causes raised blood pressure, and too much alcohol can damage the heart muscle and also increase blood pressure.3 For more information, please see the BUPA factsheet on healthy eating at: http://hcd2.bupa.co.uk/fact_sheets/html/healthy_eating.html Why is physical activity more important than weight?Obesity is associated with reduced activity levels. One suggestion is that the heart disease risk of obesity is partly explained by low fitness levels. This is because exercise has been shown to reduce the risk of heart disease and cause weight loss.1 What else could make obesity a risk for heart disease?Obesity is also associated with other heart disease risk factors such as insulin resistance.1 Insulin is a hormone that helps glucose (blood sugar) to be taken into the blood stream to provide energy to the body's cells. Being insulin resistant means that the insulin in your body does not work properly. As a result, the body's cells cannot take up enough glucose and a high level of glucose stays in the blood. A poorly controlled blood glucose level is a risk of heart disease.4 What should I do?This study suggests that concentrating on getting fitter is the best thing you can do to reduce your risk of heart disease. If you do this, it is quite likely that if you are overweight, then you will also lose some weight.1 Further informationBUPA resources:
External resources:
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