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It's Know Your Numbers Week!

9th September 2020

Do you know your numbers?

Do your know what your BMI or blood pressure should be? What is healthy and what is not? Let’s take a look...

Blood pressure (BP): your heart is a muscular pump. It pumps blood around your body using a system of blood vessels. BP is created by the force of your heart pumping blood out and the resistance of the vessel walls through which the blood passes.

BP is measured in millimetres of mercury (mmHg) and is usually written down like this: 120/70 mmHg. There are two numbers, because BP varies as the heart beats. The high number is the peak pressure created as the heart beats. The lower number is the residual pressure within the vessels as the heart rests between each beat. High BP is a reading greater than 140/90 mmHg. High BP is also known as hypertension.

Ideally, we should all have a BP below 120/80. This is the ideal BP for people wishing to have good health. At this level, we have a much lower risk of heart disease or stroke.

Most adults in the UK have BP readings between 120/80 to 140/90. If your BP is within this range, you should be taking steps to bring it down or to stop it rising any further. If you have diabetes, your doctor will want to make sure that your BP is very well controlled. This means they will probably want it to be below 130/80 mmHg.

Heart rate (or pulse): a normal resting heart rate for adults is between 60 to 100 beats a minute. Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness, e.g. a well-trained athlete might have a normal resting heart rate closer to 40 beats a minute.

You may have heard of the term “sinus rhythm”. This is the name given to the normal rhythm of the heart, where the electrical impulses that pace the heartbeat are in a regular and rhythmical manner.

Body mass index (BMI): is a value derived from the weight and height of an individual. It is an attempt to quantify the amount of tissue mass (muscle, fat and bone) in that individual and then categorise that person as underweight, normal weight, overweight, or obese based on that value. Check out www.nhs.uk/Tools/Pages/Healthyweightcalculator.aspx

Commonly accepted BMI ranges are:

  • Underweight = less than 18.5 kg/m2
  • Normal weight = 18.5 to 25 kg/m2
  • Overweight = 25 to 30 kg/m2
  • Obese = more than 30 kg/m2.

People of Asian descent have different associations between BMI, percentage body fat and health risks than those of European descent.

Blood glucose/blood sugar: The average normal blood glucose level in humans without diabetes fluctuates but it should be between 4.0 and 7.8 mmol/L.

Hyperglycaemia is the medical term for a high blood sugar level. (Greater than 11.1 mmol/L (200mg/dL)). It is a common problem for people with diabetes. It happens when the body has too little insulin or when it can’t use insulin properly. Hypoglycaemia is when a person’s blood sugar drops too low. (Less than 4 mmol/L (70mg/dL)).

Blood sugar levels are usually at their lowest in the morning, before the first meal of the day (termed the fasting level) and rise after meals for an hour or two by a few mmol/L. Blood sugar levels outside of the normal range may be an indicator of a medical condition.

If you are diabetic, your medical team will test your blood regularly for a substance called HbA1c. HbA1c differs from blood glucose levels. It is a blood protein made from a combination of haemaglobin and glucose (or sugar). The measurement allows clinicians to get an overall picture of what your average blood sugar levels have been over a period of weeks/months.

HbA1c can indicate people with pre-diabetes or diabetes as follows:

  • Normal: Below 42 mmol/mol (<6.0%)
  • Prediabetes: 42 to 47 mmol/mol (6.0%-6.4%)
  • Diabetes: >=48 mmol/mol (>=6.5%).

Cholesterol: this is a waxy, fat-like substance found in all cells of the body. Your body needs some cholesterol to make hormones, vitamin D and substances that help you to digest foods. Your body makes all the cholesterol it needs; however, it is also found in some of the foods you eat.

High blood cholesterol is a condition in which you have too much cholesterol in your blood. By itself, the condition usually has no signs or symptoms. Thus, many people don’t know that their cholesterol levels are too high. People who have a high blood cholesterol have a greater chance of getting coronary heart disease.

A cholesterol test is a blood sample which will provide a full “lipid profile”. In other words, it will measure the levels of all the different blood fats: total cholesterol, LDL- cholesterol, HDL- cholesterol, and triglyceride concentration.

Cholesterol travels through your blood stream in small packages called lipoproteins. There are two kinds: Low-density Lipoproteins (LDL) and High-density Lipoproteins (HDL):

  • LDL is sometimes called the “bad” cholesterol. A high-level leads to a buildup of cholesterol in your arteries
  • HDL is sometimes called the “good” cholesterol. This is because it carries cholesterol from other parts of your body back to the liver where it is removed.

Triglycerides are a form of dietary fat found in meats, dairy produce, and cooking oils. After eating a meal, the blood is rich in triglycerides.

It usually takes a few hours for triglyceride levels to return to normal. The higher the level of LDL cholesterol in your blood, the GREATER your chance is of getting heart disease. The higher the level of HDL cholesterol in your blood, the LOWER your chance is of getting heart disease.

Having a test is the only way you will know if you have high cholesterol. The following are considered healthy for most people:

  • Total cholesterol of 5mmol/L or less
  • Non-HDL-cholesterol of 4mmol/L or less
  • LDL-cholesterol of 3mmol/L or less
  • Fasting triglyceride of 2mmol/L or less
  • Non-fasting triglyceride of less than 4mmol/L.

Temperature: most people think a normal body temperature is an oral temperature (by mouth) of 37°C (98.6°F). This is an average of normal body temperatures. Your normal temperature may actually be 0.6°C (1°F) or more above or below this. Also, your normal temperature changes by as much as 0.6°C (1°F) during the day, depending on how active you are and the time of day and is affected by hormones.

A fever (pyrexia), in most adults, is an oral temperature above 38°C (100.4°F). A child has a fever when his or her armpit (axillary) temperature is 37.6°C (99.7°F) or higher.

Low body temperature (hypothermia) occurs when the core body temperature drops below 35.0 °C (95.0 °F). A very low body temperature can be serious or even deadly. Low body temperature usually happens from being out in cold weather. But it may also be caused by alcohol or drug use, going into shock or certain disorders such as diabetes or low thyroid.

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