Do you understand all those tests your healthcare professional runs through when you go for a general health check up? In this article we outline what’s actually being assessed when you get your blood pressure, cholesterol, triglycerides and blood sugar and BMI measured.
Blood Pressure
Your blood pressure reading is made up of two parts, usually expressed as one number ‘over’ another.
The first number is your systolic blood pressure – a measure of how much pressure there is against your arteries as your heart contracts and pumps blood around your body.
The second number is your diastolic blood pressure – a measure of how much pressure there is on the arteries as the heart relaxes before taking its next beat. It’s extremely important to maintain healthy blood pressure, as persistently high blood pressure (hypertension) is a risk factor for several serious health problems, including strokes, heart disease, memory problems and kidney failure.
On the other hand, low blood pressure may be associated with dizziness and fainting. Ideally your blood pressure should be less than 120/80 mm Hg. Blood pressure higher than this but less than 140/90 mm Hg is considered on the upper end of normal. Readings higher than 140/90 mm Hg are classified as high, and become severe at 180/110 mm Hg and above.
Cholesterol
Cholesterol has a bad reputation, but actually plays many important roles in the human body. It is an essential component of all cell membranes and is required for the production and utilisation of hormones, bile and vitamin D, as well as other metabolic processes. The liver makes virtually all the cholesterol the body needs, but we also absorb it from some of the foods we eat.
Cholesterol is transported around the body by compounds called low-density and high-density lipoproteins (LDLs and HDLs). LDLs are sometimes referred to as ‘bad’ cholesterol as they can promote the deposition of fatty deposits in the arteries impeding blood flow and make those blood vessels become hardened. HDLs, on the other hand, are sometimes called ‘good’ because they help to remove excess cholesterol from the arteries and cells.
Your cholesterol level is made up of a combined total of the two different types of cholesterol, and should ideally be less than 5.5 mmol/L. You should aim for an LDL level lower than 2 mmol/L, and an HDL higher than 1 mmol/L, and the ratio between the two different types (the LDL:HDL ratio) should be less than 3.7.
Triglycerides
When you get your cholesterol tested, your doctor will usually test your triglycerides at the same time. Like cholesterol, these fats are found in the blood stream and having a high triglyceride level is associated with an increased risk of some forms of cardiovascular disease, diabetes and some other health problems. Ideally, your triglyceride level should be less than 1.7 mmol/L.
Blood Sugar
The term blood sugar refers to how much glucose is present in your blood. Levels fluctuate according to your diet, how recently you’ve eaten and the types and quantity of food you’ve recently consumed. Blood sugar levels can also vary according to how efficiently your body is producing and using the hormone insulin, which is required in order for glucose to be converted into the energy your body needs.
Persistently higher blood sugar levels may indicate that you have diabetes, which is a serious condition – if you’re concerned that this might be the case for you, it’s important to get your blood sugar tested as soon as possible. A blood sugar level of 4.4-5.5 mmol/L is considered optimal, however if you have diabetes or are in danger of developing it, your doctor or healthcare professional may set alternative blood sugar targets.
Body Mass Index (BMI) and Waist Circumference
The body mass index (BMI) is used to determine whether you are within a healthy weight range. To determine your BMI, divide your weight in kilograms by your height in metres squared.
For example, if you are 175 centimetres tall and weigh 70 kilograms, your BMI is 24.22, calculated as 70 divided by 2.89 (1.7 x 1.7). That places your weight within the healthy BMI range of 18.5-24.99. In contrast, a BMI of less than 18.5 is considered underweight, between 25-29.99 is considered overweight, and greater than 30 is considered obese.
Although it is still in widespread use, the BMI is not a foolproof way to assess body weight, as it doesn't take factors such as your body frame into account. In many circumstances, your waist circumference may be a more appropriate measure to rely on. Carrying excess fat around your abdomen significantly increases your risk of developing a number of serious chronic health problems, including high blood pressure, high cholesterol and diabetes.
Your target waist circumference depends on your gender. If you’re a man, aim for a waist circumference below 94 centimetres if you’re Caucasian or below 90 centimetres if you’re of Asian background. For women, the target is below 80 centimetres, regardless of ethnicity .
